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  • Can't ssh tunnel to access a remote mysql server

    - by hobbes3
    I can't seem to figure out why I can't use ssh tunnel to connect to my remote MySQL server. I do ssh tunnel with [hobbes3@hobbes3] ~ $ ssh linode -L 3307:localhost:3306 Then on another terminal, I try [hobbes3@hobbes3] ~ $ mysql -h localhost -P 3307 -u root --protocol=tcp -p Enter password: ERROR 2013 (HY000): Lost connection to MySQL server at 'reading initial communication packet', system error: 2 On the server, it shows this: root@li534-120 ~ # channel 4: open failed: connect failed: Connection refused Here is my my.cnf on the server: [mysqld] # Settings user and group are ignored when systemd is used (fedora >= 15). # If you need to run mysqld under different user or group, # customize your systemd unit file for mysqld according to the # instructions in http://fedoraproject.org/wiki/Systemd user=mysql datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 # Semisynchronous Replication # http://dev.mysql.com/doc/refman/5.5/en/replication-semisync.html # uncomment next line on MASTER ;plugin-load=rpl_semi_sync_master=semisync_master.so # uncomment next line on SLAVE ;plugin-load=rpl_semi_sync_slave=semisync_slave.so # Others options for Semisynchronous Replication ;rpl_semi_sync_master_enabled=1 ;rpl_semi_sync_master_timeout=10 ;rpl_semi_sync_slave_enabled=1 # http://dev.mysql.com/doc/refman/5.5/en/performance-schema.html ;performance_schema [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid [mysqld] port = 3306 socket=/var/lib/mysql/mysql.sock skip-external-locking key_buffer_size = 64M max_allowed_packet = 128M sort_buffer_size = 512K net_buffer_length = 8K read_buffer_size = 256K read_rnd_buffer_size = 512K myisam_sort_buffer_size = 8M thread_cache = 8 max_connections = 25 query_cache_size = 16M table_open_cache = 1024 table_definition_cache = 1024 tmp_table_size = 32M max_heap_table_size = 32M bind-address = 0.0.0.0 Now sure if this helps but here is the MySQL user list: mysql> select * from mysql.user; +-----------+------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+--------+-----------------------+ | Host | User | Password | Select_priv | Insert_priv | Update_priv | Delete_priv | Create_priv | Drop_priv | Reload_priv | Shutdown_priv | Process_priv | File_priv | Grant_priv | References_priv | Index_priv | Alter_priv | Show_db_priv | Super_priv | Create_tmp_table_priv | Lock_tables_priv | Execute_priv | Repl_slave_priv | Repl_client_priv | Create_view_priv | Show_view_priv | Create_routine_priv | Alter_routine_priv | Create_user_priv | Event_priv | Trigger_priv | Create_tablespace_priv | ssl_type | ssl_cipher | x509_issuer | x509_subject | max_questions | max_updates | max_connections | max_user_connections | plugin | authentication_string | +-----------+------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+--------+-----------------------+ | localhost | root | *664328D3C5E263F4FB25185681AAE7E92B01B2B0 | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | | | | | 0 | 0 | 0 | 0 | | | | 127.0.0.1 | root | *664328D3C5E263F4FB25185681AAE7E92B01B2B0 | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | | | | | 0 | 0 | 0 | 0 | | | | ::1 | root | *664328D3C5E263F4FB25185681AAE7E92B01B2B0 | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | | | | | 0 | 0 | 0 | 0 | | | +-----------+------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+--------+-----------------------+ 3 rows in set (0.00 sec) I read about how MySQL treats localhost vs 127.0.0.1 as connecting via a socket or TCP, respectively. But I'm starting to get confused on what's really going on or if socket vs TCP is even the issue. Thanks in advance and I'm open for any tips and suggestions! Some more info: My MySQL client, running OS X 10.8.4, is mysql Ver 14.14 Distrib 5.6.10, for osx10.8 (x86_64) using EditLine wrapper My MySQL server, running on CentOS 6.4 32-bit, is mysql> SHOW VARIABLES LIKE "%version%"; +-------------------------+--------------------------------------+ | Variable_name | Value | +-------------------------+--------------------------------------+ | innodb_version | 1.1.8 | | protocol_version | 10 | | slave_type_conversions | | | version | 5.5.28 | | version_comment | MySQL Community Server (GPL) by Remi | | version_compile_machine | i686 | | version_compile_os | Linux | +-------------------------+--------------------------------------+ 7 rows in set (0.00 sec)

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  • Windows explorer locks files

    - by John Prince
    I'm using Office 2010 & Windows 7 Home Premium 64-bit. My problem starts when I attempt to save e-mail messages to my PC that I have received via Outlook (my ISP is Comcast). I'm using the default .msg file extension option when I attempt to save these e-mails. The resultant files are locked and do not show the normal "envelope" icon. Instead, it’s a “blank page” icon with the right upper corner folded in. These files refuse to open either by double clicking on them or right clicking and trying to open them with Outlook. And when I return to Outlook, I discover that Outlook is now hung up and I have to close it via the Task Manager. To make matters worse, I’ve also discovered that every e-mail message that I've saved on my PC over the years has also somehow become locked and their original "envelope" icon has been replaced with the "blank page" icon. I found and installed an application called LockHunter. As a result, when I right click on a saved and locked e-mail message, I’ve given an option to find out what's locking it. Each time I'm told that the culprit is Windows explorer.exe. When I unlock the file the normal envelope icon is sometimes displayed (but not always) but at least the file can then be opened. But the file is still “squirrely” as it can’t be moved or saved to a folder until it’s unlocked again. On this second attempt, LockHunter says it’s now locked by Outlook.exe. By the way, I don't have this issue when I save Word, Excel & PowerPoint files; only with Outlook. I've exhausted every remedy that I can think of including: making sure that the file and folder options are checked to always show icons and not thumbnails; running the Windows 7 & Office 2010 repair options which find nothing amiss; running a complete system scan with Windows Malicious Software Removal Tool with negative results; verifying that Outlook is the default for opening e-mails; updating all of my applications via Secunia Personal Software Inspector; uninstalling every application that I felt was unnecessary; doing a registry cleanup via CC Cleaner; having Windows Security Essentials always on (it did find one Java Trojan recently which was quarantined and then deleted); uninstalling a bunch of non-Microsoft shell extensions; and deactivating all of the Outlook Add-ins and then re-activating each one. None of this solves the problem. I’d welcome any advice on how to resolve this.

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  • Setting Timeouts: SQL Server 2008/IIS 7.5

    - by Julie
    We have recently migrated from a Win 2003/SQL Server 2000 system to Win 2008 64 bit R2, SQL Server 2008 R2. Our websites are in classic asp, and this can't be changed to another scripting language at this time. On the old server, if I got stuck in some kind of endless loop, the page would throw an error. On the new server, I have a page that has some sort of looping problem, that even though the SQL SP is called only once (and runs fine run as a query on the server) it pegs SQL server and therefore locks all of our websites. I'll get my code figured out, no biggie. But I need to make sure the server times out when this happens. (The page I'm working on runs fine with certain instances of the query, and locks with others using a different query variable. I can't have something like that sneak up on me on a page I haven't touched for three years.) I can't figure out how an SP that runs once on the server, from an ASP page, is tying up SQL server this way. It's obviously some sort of a timeout issue, but I can't figure out where/which timeout values to change. I actually have to remote desktop to the server and kill the process in SQL server. I'm afraid I'm a generalist, and server management is not my thing, even though it's my responsibility, so I am almost certain to have questions about any answer that I receive. How can I track this down? What settings do I need to change? More info: It's not SQL Server On our test site, I created an ASP file that just did an endless loop (do while 1=1) and had the same problem - the other websites wouldn't load - without SQL server being involved. So I think the reason the process was hanging is that the page wasn't timing out as it should, and so the connection to SQL was never closed. Killing the process in SQL server would reset the page somehow. For my intentional endless loop, I had to refresh the app pool to get rid of it. This points more to either IIS or the ASP settings. The ASP timeouts are set to whatever the default were when the server was first loaded. I still can't figure out why one file is locking up all websites, though. Again, that didn't happen on the old server.

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  • Is the master database backup crucial for restoring MS SQL server in the event where you have to res

    - by Imagineer
    I have been advise by Commvault partner support to turn off the backup of the master database as the backup failed due to the log file being lock. The following is the advise given: "The message is caused by Commvault’s inability to backup the master database’s transaction log. If this is happening intermittently its possible that something is locking the transaction log, preventing SQL iData agent from accessing the log. Typically the master database is just a template and is not used by any applications (applications that do require the use of an SQL database create their own) so there should be no harm in preventing it from being backed up You can do this by nominating NOT to back it up in the primary copy for the SQL data agent" The following is the error that I get. sqlxx SQL Server/ SQLxx N/A/ System DBs 19856* (CWE) Transaction Log N/A 01/08/2010 19:00:16 (01/08/2010 19:00:18 ) 01/08/2010 19:03:15 (01/08/2010 19:03:14 ) 1.44 MB 0:01:11 0.071 2 0 1 ITD014L2 Failure Reason: • ERROR CODE [30:325]: Error encountered during backup. Error: [ERROR: [Microsoft][ODBC SQL Server Driver][SQL Server]Cannot back up the log of the master database. Use BACKUP DATABASE instead. [Microsoft][ODBC SQL Server Driver][SQL Server]BACKUP LOG is terminating abnormally.] Job Options:Create new index, Start new media, Backup all subclients, Truncation Log, Follow mount points , Backup files protected by system file protection , Stop DHCP service when backing up system state data, Stop WINS service when backing up system state data Associated Events: • 79714 [backupxx/JobManager] [01/08/2010 19:03:15 ]: Backup job [19856] completed. Client [sqlxx], Agent Type [SQL Server], Subclient [System DBs], Backup Level [Transaction Log], Objects [2], Failed [1], Duration [00:02:59], Total Size [1.44 MB], Media or Mount Path Used [ITD014L2]. • 79712 [sqlxx/SQLiDA] [01/08/2010 19:01:53 ]: Error encountered during backup. Error: [ERROR: [Microsoft][ODBC SQL Server Driver][SQL Server]Cannot back up the log of the master database. Use BACKUP DATABASE instead. [Microsoft][ODBC SQL Server Driver][SQL Server]BACKUP LOG is terminating abnormally.] • 79711 [sqlxx/SQLiDA] [01/08/2010 19:01:51 ]: Query Result [[Microsoft][ODBC SQL Server Driver][SQL Server]Cannot back up the log of the master database. Use BACKUP DATABASE instead. [Microsoft][ODBC SQL Server Driver][SQL Server]BACKUP LOG is terminating abnormally.]. • 79707 [backupxx/JobManager] [01/08/2010 19:00:15 ]: New backup request received for Client [sqlxx], iDataAgent [SQL Server], Instance [SQLxx], Subclient [System DBs], Backup Level [Transaction Log]. Files failed to back up: • Backup Database[master] Failed Please advise, thank you.

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  • Mysql server fails to start

    - by Nicolas Thery
    Googling since two hours, I require your assistance. I'm on a Debian virtual machine and I cloned it. The only change is the new IP adress it has. Mysql doesn't start any more: Starting MySQL database server: mysqld . . . . . . . . . . . . . . failed! There is no process called mysql. All the mysql log files in /var/log are empty. here is my.cnf file : [client] port = 3306 socket = /var/run/mysqld/mysqld.sock [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] user = mysql pid-file = /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp language = /usr/share/mysql/english skip-external-locking bind-address = 127.0.0.1 key_buffer = 16M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 myisam-recover = BACKUP query_cache_limit = 1M query_cache_size = 16M general_log_file = /var/log/mysql/mysql.log log_bin = /var/log/mysql/mysql-bin.log expire_logs_days = 10 max_binlog_size = 100M [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] [isamchk] key_buffer = 16M [mysqld_safe] syslog Here is the result of ifconfig : eth0 Link encap:Ethernet HWaddr 00:0c:29:12:98:9a inet adr:192.168.1.138 Bcast:192.168.1.255 Masque:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:754 errors:0 dropped:0 overruns:0 frame:0 TX packets:106 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 lg file transmission:1000 RX bytes:101177 (98.8 KiB) TX bytes:17719 (17.3 KiB) lo Link encap:Boucle locale inet adr:127.0.0.1 Masque:255.0.0.0 adr inet6: ::1/128 Scope:Hôte UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:8 errors:0 dropped:0 overruns:0 frame:0 TX packets:8 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 lg file transmission:0 RX bytes:560 (560.0 B) TX bytes:560 (560.0 B) As requested, here is the result of : sudo -u mysql mysqld, here is the result : root@debian:/home/nicolas/Bureau# sudo -u mysql mysqld 121004 14:26:57 [Note] Plugin 'FEDERATED' is disabled. mysqld: Can't find file: './mysql/plugin.frm' (errno: 13) 121004 14:26:57 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 121004 14:26:57 InnoDB: Initializing buffer pool, size = 8.0M 121004 14:26:57 InnoDB: Completed initialization of buffer pool 121004 14:26:57 InnoDB: Started; log sequence number 0 70822697 121004 14:26:57 [Note] Recovering after a crash using /var/log/mysql/mysql-bin 121004 14:26:57 [Note] Starting crash recovery... 121004 14:26:57 [Note] Crash recovery finished. 121004 14:26:57 [ERROR] mysqld: Can't find file: './mysql/host.frm' (errno: 13) 121004 14:26:57 [ERROR] Fatal error: Can't open and lock privilege tables: Can't find file: './mysql/host.frm' (errno: 13)

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  • How to reset mysql's replication settings completely, without reinstalling it?

    - by user38060
    I set up mysql replication by adding references to binlogs, relay logs etc in my.cnf restarted mysql, it worked. I wanted to change it so I deleted all binlog related files including log-bin.index, removed binlog statements from my.cnf restarted server, works set master to '', purge master logs since now(), reset slave, stop slave, stop master. now, to set up replication again, I added binlog statements to the server. But then I hit this problem when restarting with: sudo mysqld (the only way to see mysql's startup errors) I get this error: /usr/sbin/mysqld: File '/etc/mysql/var/log-bin.index' not found (Errcode: 13) Because indeed, this file does not exist! (I deleted it, while trying to set up a new replication system) Hmm, if I change the config line to: log-bin-index = log-bin.index I get a different error: [ERROR] Can't generate a unique log-filename /etc/mysql/var/bin.(1-999) [ERROR] MSYQL_BIN_LOG::open failed to generate new file name. [ERROR] Aborting The first time I set up replication on this system, I didn't need to create this file. I did the same thing - added references to a previously non-existing file, and mysql created it. Same with relay logs, etc. I don't know why mysql insists on trying to read the old folder. Should I just reinstall the whole package again? That seems like overkill. my my.cnf: [client] port = 3306 socket = /var/run/mysqld/mysqld.sock [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] user = mysql socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp skip-external-locking bind-address = IP key_buffer = 16M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 myisam-recover = BACKUP table_cache = 64 sort_buffer =64K net_buffer_length =2K query_cache_limit = 1M query_cache_size = 16M slow_query_log_file = /etc/mysql/var/mysql-slow.log long_query_time = 1 log-queries-not-using-indexes expire_logs_days = 10 max_binlog_size = 100M server-id = 3 log-bin = /etc/mysql/var/bin.log log-slave-updates log-bin-index = /etc/mysql/var/log-bin.index log-error = /etc/mysql/var/error.log relay-log = /etc/mysql/var/relay.log relay-log-info-file = /etc/mysql/var/relay-log.info relay-log-index = /etc/mysql/var/relay-log.index auto_increment_increment = 10 auto_increment_offset = 3 master-host = HOST master-user = USER master-password=PWD replicate-do-db = DBNAME collation_server=utf8_unicode_ci character_set_server=utf8 skip-character-set-client-handshake [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] #no-auto-rehash [myisamchk] key_buffer_size = 16M sort_buffer_size = 8M [mysqlhotcopy] interactive-timeout !includedir /etc/mysql/conf.d/ Update: Changing all the /etc/mysql/var/xxx paths in binlog & relay log statements to local has somehow solved the problem. I thought it was apparmor causing it at first, but when I added /etc/mysql/* rw, to apparmor's config and restarted it, it still couldn't read the full path.

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  • MBPro, mid 2010 can't see Dlink DIR655 signal after sleep etc

    - by user88114
    This is my son's MBP 7,1 running Snow Leopard 10.6.7. Router signal is fine since iPad, Wintel on same table 20 feet from router are fine. the MBP however frequently wakes and fails to find the internet. iStumbler can see 1 neighbours hub and my garden hub are there but can't get to the normal DIR655 wifi... no ping no en0 or en1 device seems to exist. Airport off and on does not help. He just resets router and it all works but this does not please me! I must admit the winter sometimes seems to loose connect too, but less so. The DIR655 (hardware rev A3) is on the original EU firmware 1.10, I'm cautious about jumping to latest 1.31EU since no downgrade seems to be possible and that feels a bit risky as so much is set up and working fine. If I use the DIR655 admin web and release the lease the MBP has then wake it all worked OK. So I suspect lease timing/locking issue but unsure how to check up, plus why iStumbler seems to say the network is not visible at all when I sit on the iPad right next to it just fine.. I do not think there are any channel overlaps and we also have RFquiet DECT phones (Orchid) that are silent until lifted or called. Anyway signals all show low interference and high throughput except for this failure to connect. Just walked the MBP to the garden office and iStumbler now sees the more distant DIR655 signal although it will not connect to it (does not show under Sys Prefs NetNetwork names) even after airport off & on... It also refuses to connect to my garden network (an old Belkin acting as AP wired to DIR655), the signal it can see and even net name in Sys Prefs NetNetwork names (2 mins later):NOW both names ARE visible, but both fail to accept the correct WPA2 password and keep asking again after failing to connect. IT ALL MAKES NO SENSE TO ME. Just revoked the lease for the MBP on DIR655 and no changes although this seemed to help MBP wake into connection 1 hour ago. OK a bit of walking about to report. Carried MBP across garden towards DIR655, a few other wifis show up on iStumbler, low signals all channel 1. Right next to DIR655 but iStumbler not showing it, although most other wifi's have gone. I'd say iStubler is suffering timeouts&hangs but hard to be sure. Lots of attempts to Airport on/off, join other etc and suddenly I get to connect, get given new IP (I revoked), can browse. Walk away, connection drops quite soon at 30 feet then reconnected briefly then died again. MUST ATTEND ELSEWHERE FOR A BIT...

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  • How do i enable innodb on ubuntu server 10.04

    - by Matt
    Here is my entire my.cnf [client] port = 3306 socket = /var/run/mysqld/mysqld.sock # Here is entries for some specific programs # The following values assume you have at least 32M ram # This was formally known as [safe_mysqld]. Both versions are currently parsed. [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] key_buffer = 224M sort_buffer_size = 4M read_buffer_size = 4M read_rnd_buffer_size = 4M myisam_sort_buffer_size = 12M query_cache_size = 44M # # * Basic Settings # # # * IMPORTANT # If you make changes to these settings and your system uses apparmor, you may # also need to also adjust /etc/apparmor.d/usr.sbin.mysqld. # user = mysql socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp skip-external-locking # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. bind-address = 127.0.0.1 # # * Fine Tuning # #key_buffer = 16M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP #max_connections = 100 #table_cache = 64 #thread_concurrency = 10 # # * Query Cache Configuration # query_cache_limit = 1M #query_cache_size = 16M # # * Logging and Replication # # Both location gets rotated by the cronjob. # Be aware that this log type is a performance killer. # As of 5.1 you can enable the log at runtime! #general_log_file = /var/log/mysql/mysql.log #general_log = 1 log_error = /var/log/mysql/error.log # Here you can see queries with especially long duration #log_slow_queries = /var/log/mysql/mysql-slow.log #long_query_time = 2 #log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. #server-id = 1 #log_bin = /var/log/mysql/mysql-bin.log expire_logs_days = 10 max_binlog_size = 100M #binlog_do_db = include_database_name #binlog_ignore_db = include_database_name # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! # # * Security Features # # Read the manual, too, if you want chroot! # chroot = /var/lib/mysql/ # # For generating SSL certificates I recommend the OpenSSL GUI "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 16M # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/ And here is my show engines call....i have no idea what i need to do to enable innodb show engines; +------------+---------+----------------------------------------------------------------+--------------+------+------------+ | Engine | Support | Comment | Transactions | XA | Savepoints | +------------+---------+----------------------------------------------------------------+--------------+------+------------+ | MyISAM | DEFAULT | Default engine as of MySQL 3.23 with great performance | NO | NO | NO | | MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO | | BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO | | CSV | YES | CSV storage engine | NO | NO | NO | | MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO | | FEDERATED | NO | Federated MySQL storage engine | NULL | NULL | NULL | | ARCHIVE | YES | Archive storage engine | NO | NO | NO | +------------+---------+----------------------------------------------------------------+--------------+------+------------+ 7 rows in set (0.00 sec)

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  • How to keep group-writeable shares on Samba with OSX clients?

    - by Oliver Salzburg
    I have a FreeNAS server on a network with OSX and Windows clients. When the OSX clients interact with SMB/CIFS shares on the server, they are causing permission problems for all other clients. Update: I can no longer verify any answers because we abandoned the project, but feel free to post any help for future visitors. The details of this behavior seem to also be dependent on the version of OSX the client is running. For this question, let's assume a client running 10.8.2. When I mount the CIFS share on an OSX client and create a new directory on it, the directory will be created with drwxr-x-rx permissions. This is undesirable because it will not allow anyone but me to write to the directory. There are other users in my group which should have write permissions as well. This behavior happens even though the following settings are present in smb.conf on the server: [global] create mask= 0666 directory mask= 0777 [share] force directory mode= 0775 force create mode= 0660 I was under the impression that these settings should make sure that directories are at least created with rwxrwxr-x permissions. But, I guess, that doesn't stop the client from changing the permissions after creating the directory. When I create a folder on the same share from a Windows client, the new folder will have the desired access permissions (rwxrwxrwx), so I'm currently assuming that the problem lies with the OSX client. I guess this wouldn't be such an issue if you could easily change the permissions of the directories you've created, but you can't. When opening the directory info in Finder, I get the old "You have custom access" notice with no ability to make any changes. I'm assuming that this is caused because we're using Windows ACLs on the share, but that's just a wild guess. Changing the write permissions for the group through the terminal works fine, but this is unpractical for the deployment and unreasonable to expect from anyone to do. This is the complete smb.conf: [global] encrypt passwords = yes dns proxy = no strict locking = no read raw = yes write raw = yes oplocks = yes max xmit = 65535 deadtime = 15 display charset = LOCALE max log size = 10 syslog only = yes syslog = 1 load printers = no printing = bsd printcap name = /dev/null disable spoolss = yes smb passwd file = /var/etc/private/smbpasswd private dir = /var/etc/private getwd cache = yes guest account = nobody map to guest = Bad Password obey pam restrictions = Yes # NOTE: read smb.conf. directory name cache size = 0 max protocol = SMB2 netbios name = freenas workgroup = COMPANY server string = FreeNAS Server store dos attributes = yes hostname lookups = yes security = user passdb backend = ldapsam:ldap://ldap.company.local ldap admin dn = cn=admin,dc=company,dc=local ldap suffix = dc=company,dc=local ldap user suffix = ou=Users ldap group suffix = ou=Groups ldap machine suffix = ou=Computers ldap ssl = off ldap replication sleep = 1000 ldap passwd sync = yes #ldap debug level = 1 #ldap debug threshold = 1 ldapsam:trusted = yes idmap uid = 10000-39999 idmap gid = 10000-39999 create mask = 0666 directory mask = 0777 client ntlmv2 auth = yes dos charset = CP437 unix charset = UTF-8 log level = 1 [share] path = /mnt/zfs0 printable = no veto files = /.snap/.windows/.zfs/ writeable = yes browseable = yes inherit owner = no inherit permissions = no vfs objects = zfsacl guest ok = no inherit acls = Yes map archive = No map readonly = no nfs4:mode = special nfs4:acedup = merge nfs4:chown = yes hide dot files force directory mode = 0775 force create mode = 0660

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  • Server 2008/Windows 7/Samba Unspecified error 80004005

    - by ancillary
    I have a Samba share on a LAN with 2008 PDC/DNS. Smb authenticates with AD and I have several Win7 Machines that can connect fine. I recently added a couple of new computers to the LAN which were imaged the same way (same software, etc.; different hardware so different drivers) as the other machines and they have the same policies set. I can not get the new machines to connect to the samba share no matter what. I am always met with either Unspecified Error 0x80004005 or Network Path not found. I've turned off the firewall; set LANMAN auth to respond to NTLM only/send LM & NTLM responses/use NTLM session security if negotiated in Local Sec Policy SEcurity Options; tried both ip and hostname to connect. SMB log shows that authentication succeeds; but then connection is immediately killed by the client. tcpdump shows nothing remarkable except that when trying to connect from the client via hostname there is an unknown packet type error: ack 201 win 255 NBT Session Packet: Unknown packet type 0xABData: (41 bytes) Here's a couple of lines from that error: 11:18:37.964991 IP 001-client.domain.local.49372 > smb.domain.local.netbios-ssn: P 1670:2146(476) ack 201 win 255 NBT Session Packet: Unknown packet type 0xABData: (41 bytes) [000] AA 46 96 FA D5 99 33 75 0C C4 20 CE 26 42 F3 61 \252F\226\372\325\2313u \014\304 \316&B\363a [010] F0 8C FB 65 18 17 40 A5 DB 42 BB 94 37 53 92 EC \360\214\373e\030\027@\245 \333B\273\2247S\222\354 [020] 55 98 7F C4 AE 3D 6B 10 C4 U\230\177\304\256=k\020 \304 11:18:37.964998 IP smb.domain.local.netbios-ssn > 001-client.domain.local.49372: . ack 2146 win 100 Here's smb.conf just in case (though don't see how if other machines are working fine): [global] workgroup = MYDOMAIN realm = MYDOMAIN.LOCAL server string = domain|smb share interfaces = eth1 security = ADS password server = 192.168.1.3 log level = 2 log file = /var/log/samba/%m.log smb ports = 139 strict locking = no load printers = No local master = No domain master = No wins server = 192.168.1.3 wins support = Yes idmap uid = 500-10000000 idmap gid = 500-10000000 winbind separator = + winbind enum users = Yes winbind enum groups = Yes winbind use default domain = Yes [samba-share1] comment = SMB Share path = /home/share/smb/ valid users = @"MYDOMAIN+Domain Users" admin users = @"MYDOMAIN+Domain Admins" guest ok = no read only = No create mask = 0765 force directory mode = 0777 Any ideas what else I could try or look for? Or what might be the problem? Thanks.

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  • Alienware m15x (older model) BSOD investigation

    - by Crishu
    A frined of mine asked me to help him with an Alienware m15x laptop that had a little service history. It was bought in june 2008, serviced in january 2009 for a random fps drop problem, Alienware returned it saying nothing was wrong. The laptop still had hiccups, but after juggling a few drivers and settings, the fps drops weren't as noticeable. Eventually it died in Sept. 2009. It would not boot up locking itself on a white/gray screen. (i think it was overheating .. clocking in 100 degrees Celsius). So back to Alienware it went. They replaced the GPU and all was fine. Up until these blue screens started showing up. One other thing that was updated was the HDD and a Windows 7 reinstall, in August. From then on it seems to have started its BSOD. Could this be the culprit? Why? 0_o The original Windows was Vista but it was upgraded with a digital download/purchase of Windows 7 Home Premium and activated after installing windows. No errors on the old HDD, just on the latest installation. LE:Due note that now the old HDD is used to see if issues re-occur. So please, I am in need of someone who can interpret these windows dump files: Minidump I may have come to some conflicting conclusions. So if someone can clarify each dump/date and the probable cause/error it had; and a final conclusion or solution, we would be very grateful. Also please consult report for other system info I omitted: same link,code: XRWIVLWG If I missed something or if you have any other questions I'll be happy to answer them. Thank you. Good day. Processor: Intel(R) Core(TM)2 Duo CPU T9300 @ 2.50GHz Network Adapter Properties: Broadcom NetLink (TM) Gigabit Ethernet Intel(R) Wireless WiFi Link 4965AGN Video Adapter Properties: Driver Description NVIDIA GeForce 8800M GTX Driver Date 19.08.2009 Driver Version 8.16.11.8681 Driver Provider NVIDIA INF File oem19.inf Hardware ID PCI\VEN_10DE&DEV_060C&SUBSYS_0770152D&REV_A2 Location Information @system32\DRIVERS\pci.sys,#65536;PCI bus %1, device %2, function %3;(1,0,0) PCI Device NVIDIA GeForce 8800M GTX [NoDB] BIOS String Version 62.92.34.0.8 Installed Drivers nvd3dum (8.16.11.8681), nvwgf2um, nvwgf2um Hard Dik Drive: Model ID ST9120823ASG (**older one 120gb**) Model ID WD32000BEKT (new 320gb with fresh OS)

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  • APC PHP cache size does not exceed 32MB, even though settings allow for more

    - by hardy101
    I am setting up APC (v 3.1.9) on a high-traffic WordPress installation on CentOS 6.0 64 bit. I have figured out many of the quirks with APC, but something is still not quite right. No matter what settings I change, APC never actually caches more than 32MB. I'm trying to bump it up to 256 MB. 32MB is a default amount for apc.shm_size, so I am wondering if it's stuck there somehow. I have run the following echo '2147483648' > /proc/sys/kernel/shmmax to increase my system's shared memory to 2G (half of my 4G box). Then ran ipcs -lm which returns ------ Shared Memory Limits -------- max number of segments = 4096 max seg size (kbytes) = 2097152 max total shared memory (kbytes) = 8388608 min seg size (bytes) = 1 Also made a change in /etc/sysctl.conf then ran sysctl -p to make the settings stick on the server. Rebooted, too, for good measure. In my APC settings, I have mmap enabled (which happens by default in recent versions of APC). php.ini looks like: apc.stat=0 apc.shm_size="256M" apc.max_file_size="10M" apc.mmap_file_mask="/tmp/apc.XXXXXX" apc.ttl="7200" I am aware that mmap mode will ignore references to apc.shm_segments, so I have left it out with default 1. phpinfo() indicates the following about APC: Version 3.1.9 APC Debugging Disabled MMAP Support Enabled MMAP File Mask /tmp/apc.bPS7rB Locking type pthread mutex Locks Serialization Support php Revision $Revision: 308812 $ Build Date Oct 11 2011 22:55:02 Directive Local Value apc.cache_by_default On apc.canonicalize O apc.coredump_unmap Off apc.enable_cli Off apc.enabled On On apc.file_md5 Off apc.file_update_protection 2 apc.filters no value apc.gc_ttl 3600 apc.include_once_override Off apc.lazy_classes Off apc.lazy_functions Off apc.max_file_size 10M apc.mmap_file_mask /tmp/apc.bPS7rB apc.num_files_hint 1000 apc.preload_path no value apc.report_autofilter Off apc.rfc1867 Off apc.rfc1867_freq 0 apc.rfc1867_name APC_UPLOAD_PROGRESS apc.rfc1867_prefix upload_ apc.rfc1867_ttl 3600 apc.serializer default apc.shm_segments 1 apc.shm_size 256M apc.slam_defense On apc.stat Off apc.stat_ctime Off apc.ttl 7200 apc.use_request_time On apc.user_entries_hint 4096 apc.user_ttl 0 apc.write_lock On apc.php reveals the following graph, no matter how long the server runs (cache size fluctuates and hovers at just under 32MB. See image http://i.stack.imgur.com/2bwMa.png You can see that the cache is trying to allocate 256MB, but the brown piece of the pie keeps getting recycled at 32MB. This is confirmed as refreshing the apc.php page shows cached file counts that move up and down (implying that the cache is not holding onto all of its files). Does anyone have an idea of how to get APC to use more than 32 MB for its cache size?? **Note that the identical behavior occurs for eaccelerator, xcache, and APC. I read here: http://www.litespeedtech.com/support/forum/archive/index.php/t-5072.html that suEXEC could cause this problem.

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  • I can't delete a directory inside a junctioned directory

    - by Fredy Muñoz
    So this is the deal. A couple of days ago I moved my profile folder C:\Documents and Settings\fmunoz to a different drive D:\fmunoz. Today, I created a directory in my desktop using the point-and-click method: Right-click on an empty space in the desktop Select New Select Folder Leave the default name New Folder and press Enter I tried to delete the folder using the point-and-click method: Right-click the New Folder directory Select Delete After five seconds, I got the following message: --------------------------- Error Deleting File or Folder --------------------------- Cannot delete New Folder: Access is denied. Make sure the disk is not full or write-protected and that the file is not currently in use. --------------------------- Initially I thought that there must be some sort of indexing services locking the directory so I got a list of open files using the TuneUp Process Manager tool but the New Folder directory wasn't there. I double-clicked My Computer, navigated to the desktop directory C:\Documents and Settings\fmunoz\Destkop, tried to delete the New Folder directory using the same point-and-click method described above and got exactly the same message at the same amount of time. In the same window, I navigated to the actual location of the desktop directory D:\fmunoz\Desktop, tried to delete the New Folder directory and this time it worked. I thought that this behavior was due to some special treatment that Windows gives to the desktop or the profile directories so I tried doing the same thing with a different set of directories: Created a folder D:\dummy Created a junction C:\dummy pointing to D:\dummy Created a New Folder directory in C:\dummy Tried to delete New Folder from C:\dummy. Didn't work. Tried to delete New Folder from D:\dummy. It worked. I tried creating the folder in the actual directory rather than the junction directory: Created a New Folder directory in D:\dummy Tried to delete New Folder from C:\dummy. Didn't work. Tried to delete New Folder from D:\dummy. It worked. I also tried using the Delete button instead of using the Delete option of the context menu but it didn't work. When using the Shift+Delete sequence, it works. It also works by using the rd command in the console, but in both cases the deleted directory doesn't goes to the Recycle Bin, which is my intention when using the Delete context menu option or the Delete button.

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  • Why is Windows 7 not following all routes?

    - by GigabyteProductions
    My computer is connected to my secondary router that's running the 192.168.42.0/24 network and my computer also has a route that directs anything on that network to the router, but for anything on that network other than the router itself, it get's the ICMP response of Reply from 192.168.42.194: Destination host unreachable. (with 192.168.42.194 being my computer). Every other network works, like all of the internet, or addresses on my primary router like 192.168.1.*, just not on the 192.168.42.0/24 network... route print returns: IPv4 Route Table =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 192.168.42.1 192.168.42.194 276 127.0.0.0 255.0.0.0 On-link 127.0.0.1 306 127.0.0.1 255.255.255.255 On-link 127.0.0.1 306 127.255.255.255 255.255.255.255 On-link 127.0.0.1 306 192.168.42.0 255.255.255.0 On-link 192.168.42.194 276 192.168.42.194 255.255.255.255 On-link 192.168.42.194 276 192.168.42.255 255.255.255.255 On-link 192.168.42.194 276 224.0.0.0 240.0.0.0 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 192.168.42.194 276 255.255.255.255 255.255.255.255 On-link 127.0.0.1 306 255.255.255.255 255.255.255.255 On-link 192.168.42.194 276 =========================================================================== Persistent Routes: Network Address Netmask Gateway Address Metric 0.0.0.0 0.0.0.0 192.168.42.1 Default =========================================================================== The only time anything is supposed to send an ICMP Host Unreachable response is when there's no route to it, right? So, why is my own computer sending that to ping or tracert when I have the route of 192.168.42.0 with the mask of 255.255.255.0? An IP address of 192.168.42.2 surely fits into that route. If I explicitly add a route for the IP address i am trying to access, it works, like: route add 192.168.42.2 mask 255.255.255.255 192.168.42.1 (the 192.168.42.1 right after mask is gateway, or the device to send the packet to so it can route it further), but why wont it work for the implicit route that's automatically on the table? I disabled my firewall, too (I use Comodo if anyone thinks this still serves as a problem). I'v even tried explicitly adding the gateway of 192.168.42.1 to the 192.168.42.0/24 route instead of it routing through 0.0.0.0's gateway, which is what On-link does. but that didn't work either, so it's not a gateway specification problem. If the host was really unreachable, it would be the router's IP address (192.168.42.1) sending that to me... This network is all of my creation, so there's no problem such as an administrator locking me out, because i am the administrator.

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  • C#: System.Lazy&lt;T&gt; and the Singleton Design Pattern

    - by James Michael Hare
    So we've all coded a Singleton at one time or another.  It's a really simple pattern and can be a slightly more elegant alternative to global variables.  Make no mistake, Singletons can be abused and are often over-used -- but occasionally you find a Singleton is the most elegant solution. For those of you not familiar with a Singleton, the basic Design Pattern is that a Singleton class is one where there is only ever one instance of the class created.  This means that constructors must be private to avoid users creating their own instances, and a static property (or method in languages without properties) is defined that returns a single static instance. 1: public class Singleton 2: { 3: // the single instance is defined in a static field 4: private static readonly Singleton _instance = new Singleton(); 5:  6: // constructor private so users can't instantiate on their own 7: private Singleton() 8: { 9: } 10:  11: // read-only property that returns the static field 12: public static Singleton Instance 13: { 14: get 15: { 16: return _instance; 17: } 18: } 19: } This is the most basic singleton, notice the key features: Static readonly field that contains the one and only instance. Constructor is private so it can only be called by the class itself. Static property that returns the single instance. Looks like it satisfies, right?  There's just one (potential) problem.  C# gives you no guarantee of when the static field _instance will be created.  This is because the C# standard simply states that classes (which are marked in the IL as BeforeFieldInit) can have their static fields initialized any time before the field is accessed.  This means that they may be initialized on first use, they may be initialized at some other time before, you can't be sure when. So what if you want to guarantee your instance is truly lazy.  That is, that it is only created on first call to Instance?  Well, there's a few ways to do this.  First we'll show the old ways, and then talk about how .Net 4.0's new System.Lazy<T> type can help make the lazy-Singleton cleaner. Obviously, we could take on the lazy construction ourselves, but being that our Singleton may be accessed by many different threads, we'd need to lock it down. 1: public class LazySingleton1 2: { 3: // lock for thread-safety laziness 4: private static readonly object _mutex = new object(); 5:  6: // static field to hold single instance 7: private static LazySingleton1 _instance = null; 8:  9: // property that does some locking and then creates on first call 10: public static LazySingleton1 Instance 11: { 12: get 13: { 14: if (_instance == null) 15: { 16: lock (_mutex) 17: { 18: if (_instance == null) 19: { 20: _instance = new LazySingleton1(); 21: } 22: } 23: } 24:  25: return _instance; 26: } 27: } 28:  29: private LazySingleton1() 30: { 31: } 32: } This is a standard double-check algorithm so that you don't lock if the instance has already been created.  However, because it's possible two threads can go through the first if at the same time the first time back in, you need to check again after the lock is acquired to avoid creating two instances. Pretty straightforward, but ugly as all heck.  Well, you could also take advantage of the C# standard's BeforeFieldInit and define your class with a static constructor.  It need not have a body, just the presence of the static constructor will remove the BeforeFieldInit attribute on the class and guarantee that no fields are initialized until the first static field, property, or method is called.   1: public class LazySingleton2 2: { 3: // because of the static constructor, this won't get created until first use 4: private static readonly LazySingleton2 _instance = new LazySingleton2(); 5:  6: // Returns the singleton instance using lazy-instantiation 7: public static LazySingleton2 Instance 8: { 9: get { return _instance; } 10: } 11:  12: // private to prevent direct instantiation 13: private LazySingleton2() 14: { 15: } 16:  17: // removes BeforeFieldInit on class so static fields not 18: // initialized before they are used 19: static LazySingleton2() 20: { 21: } 22: } Now, while this works perfectly, I hate it.  Why?  Because it's relying on a non-obvious trick of the IL to guarantee laziness.  Just looking at this code, you'd have no idea that it's doing what it's doing.  Worse yet, you may decide that the empty static constructor serves no purpose and delete it (which removes your lazy guarantee).  Worse-worse yet, they may alter the rules around BeforeFieldInit in the future which could change this. So, what do I propose instead?  .Net 4.0 adds the System.Lazy type which guarantees thread-safe lazy-construction.  Using System.Lazy<T>, we get: 1: public class LazySingleton3 2: { 3: // static holder for instance, need to use lambda to construct since constructor private 4: private static readonly Lazy<LazySingleton3> _instance 5: = new Lazy<LazySingleton3>(() => new LazySingleton3()); 6:  7: // private to prevent direct instantiation. 8: private LazySingleton3() 9: { 10: } 11:  12: // accessor for instance 13: public static LazySingleton3 Instance 14: { 15: get 16: { 17: return _instance.Value; 18: } 19: } 20: } Note, you need your lambda to call the private constructor as Lazy's default constructor can only call public constructors of the type passed in (which we can't have by definition of a Singleton).  But, because the lambda is defined inside our type, it has access to the private members so it's perfect. Note how the Lazy<T> makes it obvious what you're doing (lazy construction), instead of relying on an IL generation side-effect.  This way, it's more maintainable.  Lazy<T> has many other uses as well, obviously, but I really love how elegant and readable it makes the lazy Singleton.

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  • mysql not starting

    - by Eiriks
    I have a server running on rackspace.com, it been running for about a year (collecting data for a project) and no problems. Now it seems mysql froze (could not connect either through ssh command line, remote app (sequel pro) or web (pages using the db just froze). I got a bit eager to fix this quick and rebooted the virtual server, running ubuntu 10.10. It is a small virtual LAMP server (10gig storage - I'm only using 1, 256mb ram -has not been a problem). Now after the reboot, I cannot get mysql to start again. service mysql status mysql stop/waiting I believe this just means mysql is not running. How do I get this running again? service mysql start start: Job failed to start No. Just typing 'mysql' gives: mysql ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (111) There is a .sock file in this folder, 'ls -l' gives: srwxrwxrwx 1 mysql mysql 0 2012-12-01 17:20 mysqld.sock From googleing this for a while now, I see that many talk about the logfile and my.cnf. Logs Not sure witch ones I should look at. This log-file is empty: 'var/log/mysql/error.log', so is the 'var/log/mysql.err' and 'var/log/mysql.log'. my.cnf is located in '/etc/mysql' and looks like this. Can't see anything clearly wrong with it either. # # The MySQL database server configuration file. # # You can copy this to one of: # - "/etc/mysql/my.cnf" to set global options, # - "~/.my.cnf" to set user-specific options. # # One can use all long options that the program supports. # Run program with --help to get a list of available options and with # --print-defaults to see which it would actually understand and use. # # For explanations see # http://dev.mysql.com/doc/mysql/en/server-system-variables.html # This will be passed to all mysql clients # It has been reported that passwords should be enclosed with ticks/quotes # escpecially if they contain "#" chars... # Remember to edit /etc/mysql/debian.cnf when changing the socket location. [client] port = 3306 socket = /var/run/mysqld/mysqld.sock # Here is entries for some specific programs # The following values assume you have at least 32M ram # This was formally known as [safe_mysqld]. Both versions are currently parsed. [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] # # * Basic Settings # # # * IMPORTANT # If you make changes to these settings and your system uses apparmor, you may # also need to also adjust /etc/apparmor.d/usr.sbin.mysqld. # user = mysql socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp skip-external-locking # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. bind-address = 127.0.0.1 # # * Fine Tuning # key_buffer = 16M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP #max_connections = 100 #table_cache = 64 #thread_concurrency = 10 # # * Query Cache Configuration # query_cache_limit = 1M query_cache_size = 16M # # * Logging and Replication # # Both location gets rotated by the cronjob. # Be aware that this log type is a performance killer. # As of 5.1 you can enable the log at runtime! #general_log_file = /var/log/mysql/mysql.log #general_log = 1 log_error = /var/log/mysql/error.log # Here you can see queries with especially long duration #log_slow_queries = /var/log/mysql/mysql-slow.log #long_query_time = 2 #log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. #server-id = 1 #log_bin = /var/log/mysql/mysql-bin.log expire_logs_days = 10 max_binlog_size = 100M #binlog_do_db = include_database_name #binlog_ignore_db = include_database_name # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! # # * Security Features # # Read the manual, too, if you want chroot! # chroot = /var/lib/mysql/ # # For generating SSL certificates I recommend the OpenSSL GUI "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 16M # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/ I need the data in the database (so i'd like to avoid reinstalling), and I need it back up running again. All hint, tips and solutions are welcomed and appreciated.

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  • Computer Networks UNISA - Chap 12 &ndash; Networking Security

    - by MarkPearl
    After reading this section you should be able to Identify security risks in LANs and WANs and design security policies that minimize risks Explain how physical security contributes to network security Discuss hardware and design based security techniques Understand methods of encryption such as SSL and IPSec, that can secure data in storage and in transit Describe how popular authentication protocols such as RADIUS< TACACS,Kerberos, PAP, CHAP, and MS-CHAP function Use network operating system techniques to provide basic security Understand wireless security protocols such as WEP, WPA and 802.11i Security Audits Before spending time and money on network security, examine your networks security risks – rate and prioritize risks. Different organizations have different levels of network security requirements. Security Risks Not all security breaches result from a manipulation of network technology – there are human factors that can play a role as well. The following categories are areas of considerations… Risks associated with People Risks associated with Transmission and Hardware Risks associated with Protocols and Software Risks associated with Internet Access An effective security policy A security policy identifies your security goals, risks, levels of authority, designated security coordinator and team members, responsibilities for each team member, and responsibilities for each employee. In addition it specifies how to address security breaches. It should not state exactly which hardware, software, architecture, or protocols will be used to ensure security, nor how hardware or software will be installed and configured. A security policy must address an organizations specific risks. to understand your risks, you should conduct a security audit that identifies vulnerabilities and rates both the severity of each threat and its likelihood of occurring. Security Policy Content Security policy content should… Policies for each category of security Explain to users what they can and cannot do and how these measures protect the networks security Should define what confidential means to the organization Response Policy A security policy should provide for a planned response in the event of a security breach. The response policy should identify the members of a response team, all of whom should clearly understand the the security policy, risks, and measures in place. Some of the roles concerned could include… Dispatcher – the person on call who first notices the breach Manager – the person who coordinates the resources necessary to solve the problem Technical Support Specialist – the person who focuses on solving the problem Public relations specialist – the person who acts as the official spokesperson for the organization Physical Security An important element in network security is restricting physical access to its components. There are various techniques for this including locking doors, security people at access points etc. You should identify the following… Which rooms contain critical systems or data and must be secured Through what means might intruders gain access to these rooms How and to what extent are authorized personnel granted access to these rooms Are authentication methods such as ID cards easy to forge etc. Security in Network Design The optimal way to prevent external security breaches from affecting you LAN is not to connect your LAN to the outside world at all. The next best protection is to restrict access at every point where your LAN connects to the rest of the world. Router Access List – can be used to filter or decline access to a portion of a network for certain devices. Intrusion Detection and Prevention While denying someone access to a section of the network is good, it is better to be able to detect when an attempt has been made and notify security personnel. This can be done using IDS (intrusion detection system) software. One drawback of IDS software is it can detect false positives – i.e. an authorized person who has forgotten his password attempts to logon. Firewalls A firewall is a specialized device, or a computer installed with specialized software, that selectively filters or blocks traffic between networks. A firewall typically involves a combination of hardware and software and may reside between two interconnected private networks. The simplest form of a firewall is a packet filtering firewall, which is a router that examines the header of every packet of data it receives to determine whether that type of packet is authorized to continue to its destination or not. Firewalls can block traffic in and out of a LAN. NOS (Network Operating System) Security Regardless of the operating system, generally every network administrator can implement basic security by restricting what users are authorized to do on a network. Some of the restrictions include things related to Logons – place, time of day, total time logged in, etc Passwords – length, characters used, etc Encryption Encryption is the use of an algorithm to scramble data into a format that can be read only by reversing the algorithm. The purpose of encryption is to keep information private. Many forms of encryption exist and new ways of cracking encryption are continually being invented. The following are some categories of encryption… Key Encryption PGP (Pretty Good Privacy) SSL (Secure Sockets Layer) SSH (Secure Shell) SCP (Secure CoPy) SFTP (Secure File Transfer Protocol) IPSec (Internet Protocol Security) For a detailed explanation on each section refer to pages 596 to 604 of textbook Authentication Protocols Authentication protocols are the rules that computers follow to accomplish authentication. Several types exist and the following are some of the common authentication protocols… RADIUS and TACACS PAP (Password Authentication Protocol) CHAP and MS-CHAP EAP (Extensible Authentication Protocol) 802.1x (EAPoL) Kerberos Wireless Network Security Wireless transmissions are particularly susceptible to eavesdropping. The following are two wireless network security protocols WEP WPA

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  • SQL SERVER – LCK_M_XXX – Wait Type – Day 15 of 28

    - by pinaldave
    Locking is a mechanism used by the SQL Server Database Engine to synchronize access by multiple users to the same piece of data, at the same time. In simpler words, it maintains the integrity of data by protecting (or preventing) access to the database object. From Book On-Line: LCK_M_BU Occurs when a task is waiting to acquire a Bulk Update (BU) lock. LCK_M_IS Occurs when a task is waiting to acquire an Intent Shared (IS) lock. LCK_M_IU Occurs when a task is waiting to acquire an Intent Update (IU) lock. LCK_M_IX Occurs when a task is waiting to acquire an Intent Exclusive (IX) lock. LCK_M_S Occurs when a task is waiting to acquire a Shared lock. LCK_M_SCH_M Occurs when a task is waiting to acquire a Schema Modify lock. LCK_M_SCH_S Occurs when a task is waiting to acquire a Schema Share lock. LCK_M_SIU Occurs when a task is waiting to acquire a Shared With Intent Update lock. LCK_M_SIX Occurs when a task is waiting to acquire a Shared With Intent Exclusive lock. LCK_M_U Occurs when a task is waiting to acquire an Update lock. LCK_M_UIX Occurs when a task is waiting to acquire an Update With Intent Exclusive lock. LCK_M_X Occurs when a task is waiting to acquire an Exclusive lock. LCK_M_XXX Explanation: I think the explanation of this wait type is the simplest. When any task is waiting to acquire lock on any resource, this particular wait type occurs. The common reason for the task to be waiting to put lock on the resource is that the resource is already locked and some other operations may be going on within it. This wait also indicates that resources are not available or are occupied at the moment due to some reasons. There is a good chance that the waiting queries start to time out if this wait type is very high. Client application may degrade the performance as well. You can use various methods to find blocking queries: EXEC sp_who2 SQL SERVER – Quickest Way to Identify Blocking Query and Resolution – Dirty Solution DMV – sys.dm_tran_locks DMV – sys.dm_os_waiting_tasks Reducing LCK_M_XXX wait: Check the Explicit Transactions. If transactions are very long, this wait type can start building up because of other waiting transactions. Keep the transactions small. Serialization Isolation can build up this wait type. If that is an acceptable isolation for your business, this wait type may be natural. The default isolation of SQL Server is ‘Read Committed’. One of my clients has changed their isolation to “Read Uncommitted”. I strongly discourage the use of this because this will probably lead to having lots of dirty data in the database. Identify blocking queries mentioned using various methods described above, and then optimize them. Partition can be one of the options to consider because this will allow transactions to execute concurrently on different partitions. If there are runaway queries, use timeout. (Please discuss this solution with your database architect first as timeout can work against you). Check if there is no memory and IO-related issue using the following counters: Checking Memory Related Perfmon Counters SQLServer: Memory Manager\Memory Grants Pending (Consistent higher value than 0-2) SQLServer: Memory Manager\Memory Grants Outstanding (Consistent higher value, Benchmark) SQLServer: Buffer Manager\Buffer Hit Cache Ratio (Higher is better, greater than 90% for usually smooth running system) SQLServer: Buffer Manager\Page Life Expectancy (Consistent lower value than 300 seconds) Memory: Available Mbytes (Information only) Memory: Page Faults/sec (Benchmark only) Memory: Pages/sec (Benchmark only) Checking Disk Related Perfmon Counters Average Disk sec/Read (Consistent higher value than 4-8 millisecond is not good) Average Disk sec/Write (Consistent higher value than 4-8 millisecond is not good) Average Disk Read/Write Queue Length (Consistent higher value than benchmark is not good) Read all the post in the Wait Types and Queue series. Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All the discussion of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • SQL SERVER – Beginning of SQL Server Architecture – Terminology – Guest Post

    - by pinaldave
    SQL Server Architecture is a very deep subject. Covering it in a single post is an almost impossible task. However, this subject is very popular topic among beginners and advanced users.  I have requested my friend Anil Kumar who is expert in SQL Domain to help me write  a simple post about Beginning SQL Server Architecture. As stated earlier this subject is very deep subject and in this first article series he has covered basic terminologies. In future article he will explore the subject further down. Anil Kumar Yadav is Trainer, SQL Domain, Koenig Solutions. Koenig is a premier IT training firm that provides several IT certifications, such as Oracle 11g, Server+, RHCA, SQL Server Training, Prince2 Foundation etc. In this Article we will discuss about MS SQL Server architecture. The major components of SQL Server are: Relational Engine Storage Engine SQL OS Now we will discuss and understand each one of them. 1) Relational Engine: Also called as the query processor, Relational Engine includes the components of SQL Server that determine what your query exactly needs to do and the best way to do it. It manages the execution of queries as it requests data from the storage engine and processes the results returned. Different Tasks of Relational Engine: Query Processing Memory Management Thread and Task Management Buffer Management Distributed Query Processing 2) Storage Engine: Storage Engine is responsible for storage and retrieval of the data on to the storage system (Disk, SAN etc.). to understand more, let’s focus on the following diagram. When we talk about any database in SQL server, there are 2 types of files that are created at the disk level – Data file and Log file. Data file physically stores the data in data pages. Log files that are also known as write ahead logs, are used for storing transactions performed on the database. Let’s understand data file and log file in more details: Data File: Data File stores data in the form of Data Page (8KB) and these data pages are logically organized in extents. Extents: Extents are logical units in the database. They are a combination of 8 data pages i.e. 64 KB forms an extent. Extents can be of two types, Mixed and Uniform. Mixed extents hold different types of pages like index, System, Object data etc. On the other hand, Uniform extents are dedicated to only one type. Pages: As we should know what type of data pages can be stored in SQL Server, below mentioned are some of them: Data Page: It holds the data entered by the user but not the data which is of type text, ntext, nvarchar(max), varchar(max), varbinary(max), image and xml data. Index: It stores the index entries. Text/Image: It stores LOB ( Large Object data) like text, ntext, varchar(max), nvarchar(max),  varbinary(max), image and xml data. GAM & SGAM (Global Allocation Map & Shared Global Allocation Map): They are used for saving information related to the allocation of extents. PFS (Page Free Space): Information related to page allocation and unused space available on pages. IAM (Index Allocation Map): Information pertaining to extents that are used by a table or index per allocation unit. BCM (Bulk Changed Map): Keeps information about the extents changed in a Bulk Operation. DCM (Differential Change Map): This is the information of extents that have modified since the last BACKUP DATABASE statement as per allocation unit. Log File: It also known as write ahead log. It stores modification to the database (DML and DDL). Sufficient information is logged to be able to: Roll back transactions if requested Recover the database in case of failure Write Ahead Logging is used to create log entries Transaction logs are written in chronological order in a circular way Truncation policy for logs is based on the recovery model SQL OS: This lies between the host machine (Windows OS) and SQL Server. All the activities performed on database engine are taken care of by SQL OS. It is a highly configurable operating system with powerful API (application programming interface), enabling automatic locality and advanced parallelism. SQL OS provides various operating system services, such as memory management deals with buffer pool, log buffer and deadlock detection using the blocking and locking structure. Other services include exception handling, hosting for external components like Common Language Runtime, CLR etc. I guess this brief article gives you an idea about the various terminologies used related to SQL Server Architecture. In future articles we will explore them further. Guest Author  The author of the article is Anil Kumar Yadav is Trainer, SQL Domain, Koenig Solutions. Koenig is a premier IT training firm that provides several IT certifications, such as Oracle 11g, Server+, RHCA, SQL Server Training, Prince2 Foundation etc. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Security, SQL Server, SQL Tips and Tricks, SQL Training, T SQL, Technology

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  • MySQL Connector/Net 6.4.6 Maintenance Release has been released

    - by fernando
    MySQL Connector/Net 6.4.6, a new version of the all-managed .NET driver for MySQL has been released.  This is a maintenance release and is recommended for use in production environments. It is appropriate for use with MySQL server versions 5.0-5.6. This is intended to be the final release for Connector/NET 6.4. It is now available in source and binary form from http://dev.mysql.com/downloads/connector/net/#downloads and mirror sites (note that not all mirror sites may be up to date at this point-if you can't find this version on some mirror, please try again later or choose another download site.) The 6.4.6 version of MySQL Connector/Net brings the following fixes: - Fix for List.Contains generates a bunch of ORs instead of more efficient IN clause in   LINQ to Entities (Oracle bug #14016344, MySql bug #64934). - Fix for error when trying to change the name of an Index on the Indexes/Keys editor; along with this fix now users can change the Index type of a new Index which could not be done   in previous versions, and when changing the Index name the change is reflected on the list view at the left side of the Index/Keys editor (Oracle bug #13613801). - Fix for stored procedure call using only its name with EF code first (MySql bug #64999, Oracle bug #14008699). - Fix for performance issue in generated EF query: .NET StartsWith/Contains/EndsWith produces MySql's locate instead of Like (MySql bug #64935, Oracle bug #14009363). - Fix for script generated for code first contains wrong alter table and wrong declaration for byte[] (MySql bug #64216, Oracle bug #13900091). - Fix for Exception thrown when using cascade delete in an EDM Model-First in Entity Framework (Oracle bug #14008752, MySql bug #64779). - Fix for Session locking issue with MySqlSessionStateStore (MySql bug #63997, Oracble bug #13733054). - Fixed deleting a user profile using Profile provider (MySQL bug #64409, Oracle bug #13790123). - Fix for bug Cannot Create an Entity with a Key of Type String (MySQL bug #65289, Oracle bug #14540202). This fix checks if the type has a FixedLength facet set in order to create a char otherwise should create varchar, mediumtext or longtext types when using a String CLR type in Code First or Model First also tested in Database First. Unit tests added for Code First and ProviderManifest. - Fix for bug "CacheServerProperties can cause 'Packet too large' error" (MySQL Bug #66578 Orabug #14593547). - Fix for handling unnamed parameter in MySQLCommand. This fix allows the mysqlcommand to handle parameters without requiring naming (e.g. INSERT INTO Test (id,name) VALUES (?, ?) ) (MySQL Bug #66060, Oracle bug #14499549). - Fixed inheritance on Entity Framework Code First scenarios. Discriminator column is created using its correct type as varchar(128) (MySql bug #63920 and Oracle bug #13582335). - Fixed "Trying to customize column precision in Code First does not work" (MySql bug #65001, Oracle bug #14469048). - Fixed bug ASP.NET Membership database fails on MySql database UTF32 (MySQL bug #65144, Oracle bug #14495292). - Fix for MySqlCommand.LastInsertedId holding only 32 bit values (MySql bug #65452, Oracle bug #14171960) by changing   several internal declaration of lastinsertid from int to long. - Fixed "Decimal type should have digits at right of decimal point", now default is 2, but user's changes in   EDM designer are recognized (MySql bug #65127, Oracle bug #14474342). - Fix for NullReferenceException when saving an uninitialized row in Entity Framework (MySql bug #66066, Oracle bug #14479715). - Fix for error when calling RoleProvider.RemoveUserFromRole(): causes an exception due to a wrong table being used (MySql bug #65805, Oracle bug #14405338). - Fix for "Memory Leak on MySql.Data.MySqlClient.MySqlCommand", too many MemoryStream's instances created (MySql bug #65696, Oracle bug #14468204). - Small improvement on MySqlPoolManager CleanIdleConnections for better mysqlpoolmanager idlecleanuptimer at startup (MySql bug #66472 and Oracle bug #14652624). - Fix for bug TIMESTAMP values are mistakenly represented as DateTime with Kind = Local (Mysql bug #66964, Oracle bug #14740705). - Fix for bug Keyword not supported. Parameter name: AttachDbFilename (Mysql bug #66880, Oracle bug #14733472). - Added support to MySql script file to retrieve data when using "SHOW" statements. - Fix for Package Load Failure in Visual Studio 2005 (MySql bug #63073, Oracle bug #13491674). - Fix for bug "Unable to connect using IPv6 connections" (MySQL bug #67253, Oracle bug #14835718). - Added auto-generated values for Guid identity columns (MySql bug #67450, Oracle bug #15834176). - Fix for method FirstOrDefault not supported in some LINQ to Entities queries (MySql bug #67377, Oracle bug #15856964). The release is available to download at http://dev.mysql.com/downloads/connector/net/6.4.html Documentation ------------------------------------- You can view current Connector/Net documentation at http://dev.mysql.com/doc/refman/5.5/en/connector-net.html You can find our team blog at http://blogs.oracle.com/MySQLOnWindows. You can also post questions on our forums at http://forums.mysql.com/. Enjoy and thanks for the support!

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  • Prevent Changing the Screen Saver and Wallpaper in Windows 7

    - by Mysticgeek
    Sometimes you might not want users to have the ability to change Screen Savers and Wallpaper on Windows 7 workstations. Today we look at how to prevent them from changing either one or both. You might administer computers in your home or small office and find it annoying when users continuously change the wallpaper and Screen Savers to something obnoxious. A lot of times they might be inexperienced users and download these so-called “wonderful and free” Screen Saver/Wallpaper packages from shady sites that include loads of Spyware. Preventing users from changing them is another helpful tool to avoid wasteful time spent switching things back. Prevent Changing Screensavers & Wallpaper Using Group Policy Editor  Note: This method uses Group Policy which is not available in Home versions on Windows 7. Open the Start Menu and enter gpedit.msc into the Search box and hit Enter. When Local Group Policy Editor opens, navigate to User Configuration \ Administrative Templates \ Control Panel \ Personalization. Then in the right column double-click on Prevent changing desktop background. Now check the radio button next to Enabled, then click OK. Back on the Group Policy Screen, double-click on Prevent changing screen saver. In the next screen select the radio button next to Enable, click OK, then close out of Group Policy Editor. Now when a user goes into the Personalization section, the Desktop Background hyperlink is now grayed out and inactive. Notice the message One or more of the settings on this page has been disabled by the system administrator at the bottom of the section. If they click to change the Screen Saver, an error message will pop up letting them know the function is disabled. Prevent Changing Screensavers & Wallpaper Using a Registry Hack You can also make a couple Registry changes to prevent users from changing the Wallpaper & Screen Saver…which will work on Home versions of Windows 7. Before making any Registry changes make sure you back it up first. Open the Registry by typing regedit into the Search box in the Start menu and hit Enter. First we’ll start with the Wallpaper. Navigate to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System and create a new String Value and name it Wallpaper. Then modify the Value data to point to the location of the Wallpaper you want it to always be. Where in this example it’s our main wallpaper on our local drive…then click OK. Now let’s make sure they can’t change the Screen Saver. In the same Registry location, we need to make a new DWORD (32-bit) Value. Give it the Value name of NoDispScrSavPage and the value data of “1” and click OK. Close out of the Registry and restart the machine or simply log off then back on again for the changes to take effect. Results For the Wallpapers, a user can still go in and see the selections, however if they try to change it to something else… It will just go back to the Personalization screen and no changes will be made, as we set the value to only be the background we specified. If the user tries to make a change to the Screen Saver, the hyperlink will be grayed out and inactive, and the message One or more of the settings on this page has been disabled by the system administrator will be displayed at the bottom of the section. Conclusion If you’re tired of users changing the Wallpaper and Screen Saver, and want another way to help avoid Malware, locking down these settings can help a lot. Again, before making any changes to the Registry, make sure to back it up. These settings should work in Vista and XP as well. Similar Articles Productive Geek Tips Save 1-4% More Battery Life With Windows Vista Battery SaverCustomize Your Windows Vista Logon ScreenEnable "Ubuntu Style" Logons in Windows VistaManage the Delete Confirmation Dialog box in Windows 7Dual Monitors: Use a Different Wallpaper on Each Desktop TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Acronis Online Backup DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows Fun with 47 charts and graphs Tomorrow is Mother’s Day Check the Average Speed of YouTube Videos You’ve Watched OutlookStatView Scans and Displays General Usage Statistics How to Add Exceptions to the Windows Firewall Office 2010 reviewed in depth by Ed Bott

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  • CLR via C# 3rd Edition is out

    - by Abhijeet Patel
    Time for some book news update. CLR via C#, 3rd Edition seems to have been out for a little while now. The book was released in early Feb this year, and needless to say my copy is on it’s way. I can barely wait to dig in and chew on the goodies that one of the best technical authors and software professionals I respect has in store. The 2nd edition of the book was an absolute treat and this edition promises to be no less. Here is a brief description of what’s new and updated from the 2nd edition. Part I – CLR Basics Chapter 1-The CLR’s Execution Model Added about discussion about C#’s /optimize and /debug switches and how they relate to each other. Chapter 2-Building, Packaging, Deploying, and Administering Applications and Types Improved discussion about Win32 manifest information and version resource information. Chapter 3-Shared Assemblies and Strongly Named Assemblies Added discussion of TypeForwardedToAttribute and TypeForwardedFromAttribute. Part II – Designing Types Chapter 4-Type Fundamentals No new topics. Chapter 5-Primitive, Reference, and Value Types Enhanced discussion of checked and unchecked code and added discussion of new BigInteger type. Also added discussion of C# 4.0’s dynamic primitive type. Chapter 6-Type and Member Basics No new topics. Chapter 7-Constants and Fields No new topics. Chapter 8-Methods Added discussion of extension methods and partial methods. Chapter 9-Parameters Added discussion of optional/named parameters and implicitly-typed local variables. Chapter 10-Properties Added discussion of automatically-implemented properties, properties and the Visual Studio debugger, object and collection initializers, anonymous types, the System.Tuple type and the ExpandoObject type. Chapter 11-Events Added discussion of events and thread-safety as well as showing a cool extension method to simplify the raising of an event. Chapter 12-Generics Added discussion of delegate and interface generic type argument variance. Chapter 13-Interfaces No new topics. Part III – Essential Types Chapter 14-Chars, Strings, and Working with Text No new topics. Chapter 15-Enums Added coverage of new Enum and Type methods to access enumerated type instances. Chapter 16-Arrays Added new section on initializing array elements. Chapter 17-Delegates Added discussion of using generic delegates to avoid defining new delegate types. Also added discussion of lambda expressions. Chapter 18-Attributes No new topics. Chapter 19-Nullable Value Types Added discussion on performance. Part IV – CLR Facilities Chapter 20-Exception Handling and State Management This chapter has been completely rewritten. It is now about exception handling and state management. It includes discussions of code contracts and constrained execution regions (CERs). It also includes a new section on trade-offs between writing productive code and reliable code. Chapter 21-Automatic Memory Management Added discussion of C#’s fixed state and how it works to pin objects in the heap. Rewrote the code for weak delegates so you can use them with any class that exposes an event (the class doesn’t have to support weak delegates itself). Added discussion on the new ConditionalWeakTable class, GC Collection modes, Full GC notifications, garbage collection modes and latency modes. I also include a new sample showing how your application can receive notifications whenever Generation 0 or 2 collections occur. Chapter 22-CLR Hosting and AppDomains Added discussion of side-by-side support allowing multiple CLRs to be loaded in a single process. Added section on the performance of using MarshalByRefObject-derived types. Substantially rewrote the section on cross-AppDomain communication. Added section on AppDomain Monitoring and first chance exception notifications. Updated the section on the AppDomainManager class. Chapter 23-Assembly Loading and Reflection Added section on how to deploy a single file with dependent assemblies embedded inside it. Added section comparing reflection invoke vs bind/invoke vs bind/create delegate/invoke vs C#’s dynamic type. Chapter 24-Runtime Serialization This is a whole new chapter that was not in the 2nd Edition. Part V – Threading Chapter 25-Threading Basics Whole new chapter motivating why Windows supports threads, thread overhead, CPU trends, NUMA Architectures, the relationship between CLR threads and Windows threads, the Thread class, reasons to use threads, thread scheduling and priorities, foreground thread vs background threads. Chapter 26-Performing Compute-Bound Asynchronous Operations Whole new chapter explaining the CLR’s thread pool. This chapter covers all the new .NET 4.0 constructs including cooperative cancelation, Tasks, the aralle class, parallel language integrated query, timers, how the thread pool manages its threads, cache lines and false sharing. Chapter 27-Performing I/O-Bound Asynchronous Operations Whole new chapter explaining how Windows performs synchronous and asynchronous I/O operations. Then, I go into the CLR’s Asynchronous Programming Model, my AsyncEnumerator class, the APM and exceptions, Applications and their threading models, implementing a service asynchronously, the APM and Compute-bound operations, APM considerations, I/O request priorities, converting the APM to a Task, the event-based Asynchronous Pattern, programming model soup. Chapter 28-Primitive Thread Synchronization Constructs Whole new chapter discusses class libraries and thread safety, primitive user-mode, kernel-mode constructs, and data alignment. Chapter 29-Hybrid Thread Synchronization Constructs Whole new chapter discussion various hybrid constructs such as ManualResetEventSlim, SemaphoreSlim, CountdownEvent, Barrier, ReaderWriterLock(Slim), OneManyResourceLock, Monitor, 3 ways to solve the double-check locking technique, .NET 4.0’s Lazy and LazyInitializer classes, the condition variable pattern, .NET 4.0’s concurrent collection classes, the ReaderWriterGate and SyncGate classes.

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  • MySQL Connector/Net 6.5.5 Maintenance Release has been released

    - by fernando
    MySQL Connector/Net 6.5.5, a new maintenance release of our 6.5 series, has been released.  This release is GA quality and is appropriate for use in production environments.  Please note that 6.6 is our latest driver series and is the recommended product for development. It is now available in source and binary form from http://dev.mysql.com/downloads/connector/net/#downloads and mirror sites (note that not all mirror sites may be up to date at this point-if you can't find this version on some mirror, please try again later or choose another download site.) The 6.5.5 version of MySQL Connector/Net brings the following fixes: - Fix for ArgumentNull exception when using Take().Count() in a LINQ to Entities query (bug MySql #64749, Oracle bug #13913047). - Fix for type varchar changed to bit when saving in Table Designer (Oracle bug #13916560). - Fix for error when trying to change the name of an Index on the Indexes/Keys editor; along with this fix now users can change the Index type of a new Index which could not be done   in previous versions, and when changing the Index name the change is reflected on the list view at the left side of the Index/Keys editor (Oracle bug #13613801). - Fix for stored procedure call using only its name with EF code first (MySql bug #64999, Oracle bug #14008699). - Fix for List.Contains generates a bunch of ORs instead of more efficient IN clause in   LINQ to Entities (Oracle bug #14016344, MySql bug #64934). - Fix for performance issue in generated EF query: .NET StartsWith/Contains/EndsWith produces MySql's locate instead of Like (MySql bug #64935, Oracle bug #14009363). - Fix for script generated for code first contains wrong alter table and wrong declaration for byte[] (MySql bug #64216, Oracle bug #13900091). - Fix and code contribution for bug Timed out sessions are removed without notification which allow to enable the Expired CallBack when Session Provider times out any session (bug MySql #62266 Oracle bug # 13354935) - Fix for Exception thrown when using cascade delete in an EDM Model-First in Entity Framework (Oracle bug #14008752, MySql bug #64779). - Fix for Session locking issue with MySqlSessionStateStore (MySql bug #63997, Oracble bug #13733054). - Fixed deleting a user profile using Profile provider (MySQL bug #64470, Oracle bug #13790123) - Fix for bug Cannot Create an Entity with a Key of Type String (MySQL bug #65289, Oracle bug #14540202). This fix checks if the type has a FixedLength facet set in order to create a char otherwise should create varchar, mediumtext or longtext types when using a String CLR type in Code First or Model First also tested in Database First. Unit tests added for Code First and ProviderManifest. - Fix for bug "CacheServerProperties can cause 'Packet too large' error". The issue was due to a missing reading of Max_allowed_packet server property when CacheServerProperties is in true, since the value was read only in the first connection but the following pooled connections had a wrong value causing a Packet too large error. Including also a unit test for this scenario. All unit test passed. MySQL Bug #66578 Orabug #14593547. - Fix for handling unnamed parameter in MySQLCommand. This fix allows the mysqlcommand to handle parameters without requiring naming (e.g. INSERT INTO Test (id,name) VALUES (?, ?) ) (MySQL Bug #66060, Oracle bug #14499549). - Fixed inheritance on Entity Framework Code First scenarios. Discriminator column is created using its correct type as varchar(128) (MySql bug #63920 and Oracle bug #13582335). - Fixed "Trying to customize column precision in Code First does not work" (MySql bug #65001, Oracle bug #14469048). - Fixed bug ASP.NET Membership database fails on MySql database UTF32 (MySQL bug #65144, Oracle bug #14495292). - Fix for MySqlCommand.LastInsertedId holding only 32 bit values (MySql bug #65452, Oracle bug #14171960) by changing   several internal declaration of lastinsertid from int to long. - Fixed "Decimal type should have digits at right of decimal point", now default is 2, but user's changes in   EDM designer are recognized (MySql bug #65127, Oracle bug #14474342). - Fix for NullReferenceException when saving an uninitialized row in Entity Framework (MySql bug #66066, Oracle bug #14479715). - Fix for error when calling RoleProvider.RemoveUserFromRole(): causes an exception due to a wrong table being used (MySql bug #65805, Oracle bug #14405338). - Fix for "Memory Leak on MySql.Data.MySqlClient.MySqlCommand", too many MemoryStream's instances created (MySql bug #65696, Oracle bug #14468204). - Added ANTLR attribution notice (Oracle bug #14379162). - Fixed Entity Framework + mysql connector/net in partial trust throws exceptions (MySql bug #65036, Oracle bug #14668820). - Added support in Parser for Datetime and Time types with precision when using Server 5.6 (No bug Number). - Small improvement on MySqlPoolManager CleanIdleConnections for better mysqlpoolmanager idlecleanuptimer at startup (MySql bug #66472 and Oracle bug #14652624). - Fix for bug TIMESTAMP values are mistakenly represented as DateTime with Kind = Local (Mysql bug #66964, Oracle bug #14740705). - Fix for bug Keyword not supported. Parameter name: AttachDbFilename (Mysql bug #66880, Oracle bug #14733472). - Added support to MySql script file to retrieve data when using "SHOW" statements. - Fix for Package Load Failure in Visual Studio 2005 (MySql bug #63073, Oracle bug #13491674). - Fix for bug "Unable to connect using IPv6 connections" (MySQL bug #67253, Oracle bug #14835718). - Added auto-generated values for Guid identity columns (MySql bug #67450, Oracle bug #15834176). - Fix for method FirstOrDefault not supported in some LINQ to Entities queries (MySql bug #67377, Oracle bug #15856964). The release is available to download at http://dev.mysql.com/downloads/connector/net/6.5.html Documentation ------------------------------------- You can view current Connector/Net documentation at http://dev.mysql.com/doc/refman/5.5/en/connector-net.html You can find our team blog at http://blogs.oracle.com/MySQLOnWindows. You can also post questions on our forums at http://forums.mysql.com/. Enjoy and thanks for the support! 

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  • Why lock-free data structures just aren't lock-free enough

    - by Alex.Davies
    Today's post will explore why the current ways to communicate between threads don't scale, and show you a possible way to build scalable parallel programming on top of shared memory. The problem with shared memory Soon, we will have dozens, hundreds and then millions of cores in our computers. It's inevitable, because individual cores just can't get much faster. At some point, that's going to mean that we have to rethink our architecture entirely, as millions of cores can't all access a shared memory space efficiently. But millions of cores are still a long way off, and in the meantime we'll see machines with dozens of cores, struggling with shared memory. Alex's tip: The best way for an application to make use of that increasing parallel power is to use a concurrency model like actors, that deals with synchronisation issues for you. Then, the maintainer of the actors framework can find the most efficient way to coordinate access to shared memory to allow your actors to pass messages to each other efficiently. At the moment, NAct uses the .NET thread pool and a few locks to marshal messages. It works well on dual and quad core machines, but it won't scale to more cores. Every time we use a lock, our core performs an atomic memory operation (eg. CAS) on a cell of memory representing the lock, so it's sure that no other core can possibly have that lock. This is very fast when the lock isn't contended, but we need to notify all the other cores, in case they held the cell of memory in a cache. As the number of cores increases, the total cost of a lock increases linearly. A lot of work has been done on "lock-free" data structures, which avoid locks by using atomic memory operations directly. These give fairly dramatic performance improvements, particularly on systems with a few (2 to 4) cores. The .NET 4 concurrent collections in System.Collections.Concurrent are mostly lock-free. However, lock-free data structures still don't scale indefinitely, because any use of an atomic memory operation still involves every core in the system. A sync-free data structure Some concurrent data structures are possible to write in a completely synchronization-free way, without using any atomic memory operations. One useful example is a single producer, single consumer (SPSC) queue. It's easy to write a sync-free fixed size SPSC queue using a circular buffer*. Slightly trickier is a queue that grows as needed. You can use a linked list to represent the queue, but if you leave the nodes to be garbage collected once you're done with them, the GC will need to involve all the cores in collecting the finished nodes. Instead, I've implemented a proof of concept inspired by this intel article which reuses the nodes by putting them in a second queue to send back to the producer. * In all these cases, you need to use memory barriers correctly, but these are local to a core, so don't have the same scalability problems as atomic memory operations. Performance tests I tried benchmarking my SPSC queue against the .NET ConcurrentQueue, and against a standard Queue protected by locks. In some ways, this isn't a fair comparison, because both of these support multiple producers and multiple consumers, but I'll come to that later. I started on my dual-core laptop, running a simple test that had one thread producing 64 bit integers, and another consuming them, to measure the pure overhead of the queue. So, nothing very interesting here. Both concurrent collections perform better than the lock-based one as expected, but there's not a lot to choose between the ConcurrentQueue and my SPSC queue. I was a little disappointed, but then, the .NET Framework team spent a lot longer optimising it than I did. So I dug out a more powerful machine that Red Gate's DBA tools team had been using for testing. It is a 6 core Intel i7 machine with hyperthreading, adding up to 12 logical cores. Now the results get more interesting. As I increased the number of producer-consumer pairs to 6 (to saturate all 12 logical cores), the locking approach was slow, and got even slower, as you'd expect. What I didn't expect to be so clear was the drop-off in performance of the lock-free ConcurrentQueue. I could see the machine only using about 20% of available CPU cycles when it should have been saturated. My interpretation is that as all the cores used atomic memory operations to safely access the queue, they ended up spending most of the time notifying each other about cache lines that need invalidating. The sync-free approach scaled perfectly, despite still working via shared memory, which after all, should still be a bottleneck. I can't quite believe that the results are so clear, so if you can think of any other effects that might cause them, please comment! Obviously, this benchmark isn't realistic because we're only measuring the overhead of the queue. Any real workload, even on a machine with 12 cores, would dwarf the overhead, and there'd be no point worrying about this effect. But would that be true on a machine with 100 cores? Still to be solved. The trouble is, you can't build many concurrent algorithms using only an SPSC queue to communicate. In particular, I can't see a way to build something as general purpose as actors on top of just SPSC queues. Fundamentally, an actor needs to be able to receive messages from multiple other actors, which seems to need an MPSC queue. I've been thinking about ways to build a sync-free MPSC queue out of multiple SPSC queues and some kind of sign-up mechanism. Hopefully I'll have something to tell you about soon, but leave a comment if you have any ideas.

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  • MySQL Connect Only 10 Days Away - Focus on InnoDB Sessions

    - by Bertrand Matthelié
    Time flies and MySQL Connect is only 10 days away! You can check out the full program here as well as in the September edition of the MySQL newsletter. Mat recently blogged about the MySQL Cluster sessions you’ll have the opportunity to attend, and below are those focused on InnoDB. Remember you can plan your schedule with Schedule Builder. Saturday, 1.00 pm, Room Golden Gate 3: 10 Things You Should Know About InnoDB—Calvin Sun, Oracle InnoDB is the default storage engine for Oracle’s MySQL as of MySQL Release 5.5. It provides the standard ACID-compliant transactions, row-level locking, multiversion concurrency control, and referential integrity. InnoDB also implements several innovative technologies to improve its performance and reliability. This presentation gives a brief history of InnoDB; its main features; and some recent enhancements for better performance, scalability, and availability. Saturday, 5.30 pm, Room Golden Gate 4: Demystified MySQL/InnoDB Performance Tuning—Dimitri Kravtchuk, Oracle This session covers performance tuning with MySQL and the InnoDB storage engine for MySQL and explains the main improvements made in MySQL Release 5.5 and Release 5.6. Which setting for which workload? Which value will be better for my system? How can I avoid potential bottlenecks from the beginning? Do I need a purge thread? Is it true that InnoDB doesn't need thread concurrency anymore? These and many other questions are asked by DBAs and developers. Things are changing quickly and constantly, and there is no “silver bullet.” But understanding the configuration setting’s impact is already a huge step in performance improvement. Bring your ideas and problems to share them with others—the discussion is open, just moderated by a speaker. Sunday, 10.15 am, Room Golden Gate 4: Better Availability with InnoDB Online Operations—Calvin Sun, Oracle Many top Web properties rely on Oracle’s MySQL as a critical piece of infrastructure for serving millions of users. Database availability has become increasingly important. One way to enhance availability is to give users full access to the database during data definition language (DDL) operations. The online DDL operations in recent MySQL releases offer users the flexibility to perform schema changes while having full access to the database—that is, with minimal delay of operations on a table and without rebuilding the entire table. These enhancements provide better responsiveness and availability in busy production environments. This session covers these improvements in the InnoDB storage engine for MySQL for online DDL operations such as add index, drop foreign key, and rename column. Sunday, 11.45 am, Room Golden Gate 7: Developing High-Throughput Services with NoSQL APIs to InnoDB and MySQL Cluster—Andrew Morgan and John Duncan, Oracle Ever-increasing performance demands of Web-based services have generated significant interest in providing NoSQL access methods to MySQL (MySQL Cluster and the InnoDB storage engine of MySQL), enabling users to maintain all the advantages of their existing relational databases while providing blazing-fast performance for simple queries. Get the best of both worlds: persistence; consistency; rich SQL queries; high availability; scalability; and simple, flexible APIs and schemas for agile development. This session describes the memcached connectors and examines some use cases for how MySQL and memcached fit together in application architectures. It does the same for the newest MySQL Cluster native connector, an easy-to-use, fully asynchronous connector for Node.js. Sunday, 1.15 pm, Room Golden Gate 4: InnoDB Performance Tuning—Inaam Rana, Oracle The InnoDB storage engine has always been highly efficient and includes many unique architectural elements to ensure high performance and scalability. In MySQL 5.5 and MySQL 5.6, InnoDB includes many new features that take better advantage of recent advances in operating systems and hardware platforms than previous releases did. This session describes unique InnoDB architectural elements for performance, new features, and how to tune InnoDB to achieve better performance. Sunday, 4.15 pm, Room Golden Gate 3: InnoDB Compression for OLTP—Nizameddin Ordulu, Facebook and Inaam Rana, Oracle Data compression is an important capability of the InnoDB storage engine for Oracle’s MySQL. Compressed tables reduce the size of the database on disk, resulting in fewer reads and writes and better throughput by reducing the I/O workload. Facebook pushes the limit of InnoDB compression and has made several enhancements to InnoDB, making this technology ready for online transaction processing (OLTP). In this session, you will learn the fundamentals of InnoDB compression. You will also learn the enhancements the Facebook team has made to improve InnoDB compression, such as reducing compression failures, not logging compressed page images, and allowing changes of compression level. Not registered yet? You can still save US$ 300 over the on-site fee – Register Now!

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