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  • Most hazardous performance bottleneck misconceptions

    - by David Murdoch
    The guys who wrote Bespin (cloud-based canvas-based code editor [and more]) recently spoke about how they re-factored and optimize a portion of the Bespin code because of a misconception that JavaScript was slow. It turned out that when all was said and done, their optimization produced no significant improvements. I'm sure many of us go out of our way to write "optimized" code based on misconceptions similar to that of the Bespin team. What are some common performance bottleneck misconceptions developers commonly subscribe to?

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  • Mathematics - Why is Differential Calculus (MVP) in PHP a tabu?

    - by Email
    Hi I want to do a Mean-Variance-Optimization (Markowitz) but i never found anything written in php that does this. MVP needs differential calculus. Can it be done in php and why arent there any classes/works from universities? For a webapplication (regarding performance) would another language be the better choice to handle heavy calculations? Thanks so much for any help/answer on this

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  • JavaScript tags, performance and W3C

    - by Thomas
    Today I was looking for website optimization content and I found an article talking about move JavaScript scripts to the bottom of the HTML page. Is this valid with W3C's recommendations? I learned that all JavaScript must be inside of head tag... Thank you.

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  • Heap Behavior in C++

    - by wowus
    Is there anything wrong with the optimization of overloading the global operator new to round up all allocations to the next power of two? Theoretically, this would lower fragmentation at the cost of higher worst-case memory consumption, but does the OS already have redundant behavior with this technique, or does it do its best to conserve memory? Basically, given that memory usage isn't as much of an issue as performance, should I do this?

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  • Optimizing apache server load

    - by Jevgeni Smirnov
    We have an issue with a dedicated server load. We have 16 processors with 4 core @ 2.40GHz, if I understood correctly cat /proc/cpuinfo output. Unfortunately, I don't have access to free -m or vmstat. But from top I got that we have 24 GB. And snapshot from top about processes: As far as I see, memory is not used at all. But the cpu is used heavily. Apache consumes most of CPU. Another useful piece of information: Every 1.0s: ps u -C httpd,mysqld,php Tue Mar 27 10:48:19 2012 USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 7476 0.0 0.1 446808 37880 ? SNs Mar06 0:43 /opt/zone/sbin/httpd -D SSL -D SLOT_ID0 -f /etc/opt/zone/apache/ssl_httpd.conf mysql 36061 41.6 2.1 1113672 529876 ? SNl Feb20 21503:48 /opt/zone/sbin/mysqld --basedir=/opt/zone --datadir=/srvdata/mysql --user=mysql --log-error=/srvdata/mysql/dn79.err --pid-file=/srvdata/mysql/mysqld.pid --socket=/tmp/mysql.sock --port=3306 root 37257 0.0 0.0 424056 16840 ? SNs Mar22 1:03 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 52743 0.0 0.1 447100 30360 ? SN 10:40 0:00 /opt/zone/sbin/httpd -D SSL -D SLOT_ID0 -f /etc/opt/zone/apache/ssl_httpd.conf http 52744 0.0 0.1 447100 30360 ? SN 10:40 0:00 /opt/zone/sbin/httpd -D SSL -D SLOT_ID0 -f /etc/opt/zone/apache/ssl_httpd.conf http 52745 0.0 0.1 447100 30360 ? SN 10:40 0:00 /opt/zone/sbin/httpd -D SSL -D SLOT_ID0 -f /etc/opt/zone/apache/ssl_httpd.conf http 52746 0.0 0.1 447100 30360 ? SN 10:40 0:00 /opt/zone/sbin/httpd -D SSL -D SLOT_ID0 -f /etc/opt/zone/apache/ssl_httpd.conf http 52747 0.0 0.1 446956 30324 ? SN 10:40 0:00 /opt/zone/sbin/httpd -D SSL -D SLOT_ID0 -f /etc/opt/zone/apache/ssl_httpd.conf http 52980 69.1 1.8 852468 458088 ? RN 10:41 5:02 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 53483 47.0 0.8 615088 221040 ? RN 10:43 2:05 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 53641 1.8 0.2 446580 54632 ? SN 10:45 0:03 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54384 81.2 0.9 625828 229972 ? RN 10:45 2:14 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54411 47.7 0.5 535992 142416 ? RN 10:45 1:09 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54470 41.7 0.4 512528 120012 ? RN 10:46 0:54 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54475 0.1 0.1 437016 41528 ? SN 10:46 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54486 1.5 0.2 445636 53916 ? SN 10:46 0:02 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54531 2.5 0.2 445424 53012 ? SN 10:46 0:02 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54549 0.0 0.0 424188 9188 ? SN 10:46 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54642 0.0 0.0 424188 9200 ? SN 10:47 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54651 0.0 0.0 424188 9188 ? SN 10:47 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54661 0.0 0.0 424188 9208 ? SN 10:47 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54663 6.9 0.2 449936 58560 ? SN 10:47 0:03 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54666 6.0 0.2 453356 61124 ? SN 10:47 0:02 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54667 2.8 0.1 437608 42088 ? SN 10:47 0:01 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54670 1.5 0.1 437540 42172 ? SN 10:47 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54672 2.1 0.1 439076 43648 ? SN 10:47 0:01 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54709 0.0 0.0 424188 9192 ? SN 10:47 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54711 1.0 0.1 437284 41780 ? SN 10:47 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54712 11.8 0.2 448172 54700 ? SN 10:47 0:02 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54720 0.0 0.0 424188 9192 ? SN 10:48 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54721 0.0 0.0 424188 9188 ? SN 10:48 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54747 9.1 0.2 443568 51848 ? SN 10:48 0:01 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54782 1.8 0.1 438708 37896 ? RN 10:48 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54784 0.0 0.0 424188 9180 ? SN 10:48 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54785 0.0 0.0 424188 9188 ? SN 10:48 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54789 0.0 0.0 424188 9188 ? SN 10:48 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54790 0.0 0.0 424188 9188 ? SN 10:48 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54791 0.0 0.0 424188 9188 ? SN 10:48 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 http 54792 0.0 0.0 424056 8352 ? SN 10:48 0:00 /opt/zone/sbin/httpd -f /etc/opt/zone/apache/httpd.conf -D SLOT_ID0 Webalizer shows following: What can be done in the following situation? The application is Magento.

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  • PostgreSQL lots of writes

    - by strife911
    Hi, I am using postgreSQL for a scientific application (unsupervised clustering). The python program is multi-threaded so that each thread manages its own postmaster process (one per core). Hence, their is a lot of concurrency. Each thread-process loop infinitely though two SQL queries. The first is for reading, the second is for writing. The read operation considers 500 time the amount of rows the write operation considers. Here is the output of dstat: ----total-cpu-usage---- ------memory-usage----- -dsk/total- --paging-- --io/total- usr sys idl wai hiq siq| used buff cach free| read writ| in out | read writ 4 0 32 64 0 0|3599M 63M 57G 1893M|1524k 16M| 0 0 | 98 2046 1 0 35 64 0 0|3599M 63M 57G 1892M|1204k 17M| 0 0 | 68 2062 2 0 32 66 0 0|3599M 63M 57G 1890M|1132k 17M| 0 0 | 62 2033 2 1 32 65 0 0|3599M 63M 57G 1904M|1236k 18M| 0 0 | 80 1994 2 0 31 67 0 0|3599M 63M 57G 1903M|1312k 16M| 0 0 | 70 1900 2 0 37 60 0 0|3599M 63M 57G 1899M|1116k 15M| 0 0 | 71 1594 2 1 37 60 0 0|3599M 63M 57G 1898M| 448k 17M| 0 0 | 39 2001 2 0 25 72 0 0|3599M 63M 57G 1896M|1192k 17M| 0 0 | 78 1946 1 0 40 58 0 0|3599M 63M 57G 1895M| 432k 15M| 0 0 | 38 1937 I am pretty sure I could write more often than that for I have seen it write up to 110-140M on dstat. How can I optimize this process?

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  • XDEBUG/PHP doesn't dump profile even when set up properly?

    - by John D.
    I installed xdebug from source, but also tried my package manager (separately) and they both are loaded correctly (verified by restarting Apache and seeing the xdebug copyright info in phpinfo()) but they do not dump profiling information. Out of the 40 different attempts of configuration it logged once or twice but I lost what I did, I tried with first only loading the module in php.ini with no settings, but it didn't log to /tmp/. I tried many different settings but my current is now: xdebug.profiler_enable = Off xdebug.profiler_enable_trigger = 1 xdebug.profiler_output_dir = "/tmp/" xdebug.profiler_output_name = "profiler.%t" Of course I call my script through 127.0.0.1/test.php?XDEBUG_PROFILE, which is for enable_trigger. Do you know why it would not dump profiler information? nobody (Arch Linux) can write to /tmp/ as it has before, so I'm sure it is not a permissions error. Apache's error_log does not tell me anything about xdebug either, as it has loaded correctly. It just does not "work"! EDIT: I made a subfolder "xdebug_profiles" in /tmp/ and chown'ed it to nobody, and now it works flawlessly. I'm not sure why it couldn't write before, I guess it's just a caveat with nobody on Arch. I answered my own question , not enough points to answer it or comment, so consider this answered.

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  • CPU's on Hyper-V host system is just idling, even though VM's are at full throttle

    - by Bjørn
    Hello, I have a server that is running Windows 2008 64 bit Hyper-V, with 8 gigs of RAM and Intel Xeon X3440 @ 2.53 Ghz, which gives me 8 logical cores in the performance monitor on the host system. I have set up three Virtual Machines, all running Windows 2008 32 bit. Build server, running Team City Staging server SQL Server, running SQL Server 2005 These three machines are running very sluggishly, they are at 100% cpu even though the host system is barely using any cpu at all, typically below 10% total. Could anyone please give some tips as to the best setup for CPU allocating? Should I have set each server to have two cores, or should I increase this number above the total number of cores on the host? What is a good number to set on the Virtual Machine Reserve and Virtual Machine Limit? Is 8 gigs of physical RAM insufficient for 3 VM's? Thanks for reading. :)

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  • Serving images from another hostname vs Apache overload for the rewrites

    - by luison
    We are trying to improve further the speed of some sites with older HTML in order as well to obtain better SEO results. We have now applied some minify measures, combined html, css etc. We use a small virtualized infrastructure and we've always wanted to use a light + standar http server configuration so the first one can serve images and static contents vs the other one php, rewrites, etc. We can easily do that now with a VM using the same files and conf of vhosts (bind mounts) on apache but with hardly any modules loaded. This means the light httpd will have smaller fingerprint that would allow us to serve more and quicker, have more minSpareServer running, etc. So, as browsers benefit from loading static content from different hostnames as well, we've thought about building a rewrite rule on our main server (main.com) to "redirect" all images and css *.jpg, *.gif, *.css etc to the same at say cdn.main.com thus the browser being able to have more connections. The question is, assuming we have a very complex rewrite ruleset already (we manually manipulate many old URLs for SEO) will it be worth? I mean will the additional load of main's apache to have to redirect main.com/image.jpg (I understand we'll have to do a 301) to cdn.main.com/image.jpg + then cdn.main.com having to serve it, be larger than the gain we would be archiving on the browser? Could the excess of 301s of all images on a page be penalized by google? How do large companies work this out, does the original code already include images linked from the cdn with absolute paths? EDIT Just to clarify, our concern is not to do so much with server performance or bandwith. We could obviously employ an external CDN server but we have plenty CPU and bandwith. Our concern is with how to have "old" sites with plenty semi-static HTML content benefiting from splitting connections for images and static content via apache without having to change the html to absolute paths (ie. image.jpg to cdn.main.com/image.jpg happening on the server not the code)

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  • Disable Memory Modules In BIOS for Testing Purposes (Optimize Nehalem/Gulftown Memory Performance)

    - by Bob
    I recently acquired an HP Z800 with two Intel Xeon X5650 (Gulftown) 6 core processors. The person that configured the system chose 16GB (8 x 2GB DDR3-1333). I'm assuming this person was unaware these processors have 3 memory channels and to optimize memory performance one should choose memory in multiples of three. Based on this information, I have a question: By entering the BIOS, can I disable the bank on each processor that has the single memory module? If so, will this have any adverse effects or behave differently than physically removing the modules? I ask due to the fact that I prefer to store the extra memory in the system if it truly behaves as if the memory is not even there. Also, I see this as an opportunity to test 12GB vs. 16GB to see if there is a noticeable difference. Note: According to http://www.delltechcenter.com/page/04-08-2009+-+Nehalem+and+Memory+Configurations?t=anon, the current configuration reduces the overall data transfer speed to 1066 and in addition, the memory bandwidth goes down by about 23%.

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  • Optimizing MySQL for small VPS

    - by Chris M
    I'm trying to optimize my MySQL config for a verrry small VPS. The VPS is also running NGINX/PHP-FPM and Magento; all with a limit of 250MB of RAM. This is an output of MySQL Tuner... -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.1.41-3ubuntu12.8 [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in MyISAM tables: 1M (Tables: 14) [--] Data in InnoDB tables: 29M (Tables: 301) [--] Data in MEMORY tables: 1M (Tables: 17) [!!] Total fragmented tables: 301 -------- Security Recommendations ------------------------------------------- [OK] All database users have passwords assigned -------- Performance Metrics ------------------------------------------------- [--] Up for: 2d 11h 14m 58s (1M q [8.038 qps], 33K conn, TX: 2B, RX: 618M) [--] Reads / Writes: 83% / 17% [--] Total buffers: 122.0M global + 8.6M per thread (100 max threads) [!!] Maximum possible memory usage: 978.2M (404% of installed RAM) [OK] Slow queries: 0% (37/1M) [OK] Highest usage of available connections: 6% (6/100) [OK] Key buffer size / total MyISAM indexes: 32.0M/282.0K [OK] Key buffer hit rate: 99.7% (358K cached / 1K reads) [OK] Query cache efficiency: 83.4% (1M cached / 1M selects) [!!] Query cache prunes per day: 48301 [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 144K sorts) [OK] Temporary tables created on disk: 13% (27K on disk / 203K total) [OK] Thread cache hit rate: 99% (6 created / 33K connections) [!!] Table cache hit rate: 0% (32 open / 51K opened) [OK] Open file limit used: 1% (20/1K) [OK] Table locks acquired immediately: 99% (1M immediate / 1M locks) [!!] InnoDB data size / buffer pool: 29.2M/8.0M -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance Reduce your overall MySQL memory footprint for system stability Enable the slow query log to troubleshoot bad queries Increase table_cache gradually to avoid file descriptor limits Variables to adjust: *** MySQL's maximum memory usage is dangerously high *** *** Add RAM before increasing MySQL buffer variables *** query_cache_size (> 64M) table_cache (> 32) innodb_buffer_pool_size (>= 29M) and this is the config. # # 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 = 32M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 sort_buffer_size = 4M read_buffer_size = 4M myisam_sort_buffer_size = 16M # 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 = 32 tmp_table_size = 128M #thread_concurrency = 10 # # * Query Cache Configuration # #query_cache_limit = 1M query_cache_type = 1 query_cache_size = 64M # # * 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/ The site contains 1 wordpress site,so lots of MYISAM but mostly static content as its not changing all that often (A wordpress cache plugin deals with this). And the Magento Site which consists of a lot of InnoDB tables, some MyISAM and some INMEMORY. The "read" side seems to be running pretty well with a mass of optimizations I've used on Magento, the NGINX setup and PHP-FPM + XCACHE. I'd love to have a kick in the right direction with the MySQL config so I'm not blindly altering it based on the MySQLTuner without understanding what I'm changing. Thanks

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  • Monitoring outgoing bandwidth of application

    - by jnolte
    I currently have a VPS that is consuming a ton of outgoing bandwidth and I am trying to drill down to where this may be coming from. Does anyone know of a logical way to go about finding out which pages on the site are consuming the most outgoing data. We have done a ton of front-end optimizations to the site and our google page speed rankings ar 85% so I feel we have done a pretty great job at optimizing the site for speed. Can someone lend some insight on how they have made similar optimizations? Application / Server Stack LEMP Running Varnish Cache / PHP5-FPM WordPress running w3 Total Cache Ubuntu 12.04 LTS

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  • Better way to design a database

    - by cMinor
    I have a conceptual problem and I would like to get your ideas on how I'll be able to do what I am aiming. My goal is to create a database with information of persons who work at a place depending on their profession and skills,and keep control of salary and projects (how much would cost summing all the hours of work) I have 3 categories which can have subcategories: Outsourcing Technician welder turner assistant Administrative supervisor manager So each person has its information and the projects they are working on, also one person may do several jobs... I was thinking about having 5 tables (EMPLOYEE, SKILLS, PROYECTS, SALARY, PROFESSION) but I guess there is a better way of doing this. create table Employee ( PRIMARY KEY [Person_ID] int(10), [Name] varchar(30), [sex] varchar(10), [address] varchar(10), [profession] varchar(10), [Skills_ID] int(10), [Proyect_ID] int(10), [Salary_ID] int(10), [Salary] float ) create table Skills ( PRIMARY KEY [Skills_ID] int(10), FOREIGN KEY [Skills_name] varchar(10) REFERENCES Employee(Person_ID), [Skills_pay] float(10), [Comments] varchar(50) ) create table Proyects ( PRIMARY KEY [Proyect_ID] int(10), FOREIGN KEY [Skills_name] varchar(10) REFERENCES Employee(Person_ID) [Proyect_name] varchar(10), [working_Hours] float(10), [Comments] varchar(50) ) create table Salary ( PRIMARY KEY [Salary_ID] int(10), FOREIGN KEY [Skills_name] varchar(10) REFERENCES Employee(Person_ID) [Proyect_name] varchar(10), [working_Hours] float(10), [Comments] varchar(50) ) So to get the total amount of the cost of a project I would just sum the working hours of each employee envolved and sum some extra costs in an aggregate query. Is there a way to do this in a more efficient way? What to add or delete of this small model? I guess I am missing something in the salary - maybe I need another table for that?

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  • Looking for a short term solution to improve website performance with additional server

    - by Tanim Mirza
    I am working with a small team to run an internal website running with PHP 5.3.9, MySQL 5.0.77. All the files and database are hosted on a dedicated Linux machine with the following configuration: Intel Xeon E5450 8 CPU cores @3.00GHz, 2992.498 MHz, Cache 6148 KB, Cent OS – Red Hat Enterprise Linux Server release 5.4 We started small and then the database got bigger and now the website performance degraded significantly. We often get server space overrun, mysql overloaded with too many calls, etc. We don't have much experience dealing with these issues. We recently got another server that we were thinking to use to improve performance. Since it has better configuration, some of us wanted to completely move everything to the new machine. But I am trying to find out how we can utilize both machine for optimized performance. I found options such as MySQL clustering, Load balancer, etc. I was wondering if I could get any suggestion for this situation "How to utilize two machines in short term for best performance", that would be great. By short term we are looking for something that we can deploy in a month or so. Thanks in advance for your time.

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  • Optimize windows 2008 performance

    - by Giorgi
    Hello, I have windows server 2008 sp2 installed as virtual machine on my personal laptop. I use it only for source control (visual svn) and continuous integration (teamcity). As the virtual machine resources are limited I'd like to optimize it's performance by disabling services and features that are not necessary for my purposes. Can anyone recommend where to start or provide with tips for getting better performance. Thanks.

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  • Open Source Scheduling Software?

    - by Kaiser Advisor
    Hi Everyone, I'm looking for scheduling software to schedule 25 people over 8 work sites. Most are FT and can work up to 40 hours a week, but some are part-time and can only work certain days of the week and up to a certain number of hours a week. There are 3 classes of employees: Managers, Supervisors, and Workers. They should be shuffled so that they spend approximately equal time at each of the 8 work sites and with all classes of employees; i.e., Joe the worker should spend about 1 out of 8 days on each work site, and work with managers, supervisors, and other workers equally. I tried to do this in excel with the solver, but the shuffling requirement makes it way too complicated, so I'm stuck trying to do big parts of this manually with the solver helping out with just the hour provisioning piece. Is there any open source software that could help me? Much appreciated! KA

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  • write-through RAM disk, or massive caching of file system?

    - by Will
    I have a program that is very heavily hitting the file system, reading and writing randomly to a set of working files. The files total several gigabytes in size, but I can spare the RAM to keep them all mostly in memory. The machines this program runs on are typically Ubuntu Linux boxes. Is there a way to configure the file system to have a very very large cache, and even to cache writes so they hit the disk later? I understand the issues with power loss or such, and am prepared to accept that. Crashing aside, in normal operation the writes should eventually reach the disk! Or is there a way to create a RAM disk that writes-through to real disk?

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  • How do I optimize TCP stack for HTTP server?

    - by jcisio
    I have a HTTP server that serves only two kinds of page: about 10 KB and about 16 KB (both compressed, other files are from CDN). As the latency is quite high (ping takes more than 300 ms), I want to optimize the TCP stack so that client receives the whole page ASAP. Thus, I have a double question: Which parameter do I have to change (which value of TCP window)? How to change in (a Debian box, and FYI, there is a Varnish before the HTTP server).

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  • Optimize shell and awk script

    - by bryan
    I am using a combination of a shell script, awk script and a find command to perform multiple text replacements in hundreds of files. The files sizes vary between a few hundred bytes and 20 kbytes. I am looking for a way to speed up this script. I am using cygwin. The shell script - #!/bin/bash if [ $# = 0 ]; then echo "Argument expected" exit 1 fi while [ $# -ge 1 ] do if [ ! -f $1 ]; then echo "No such file as $1" exit 1 fi awk -f ~/scripts/parse.awk $1 > ${1}.$$ if [ $? != 0 ]; then echo "Something went wrong with the script" rm ${1}.$$ exit 1 fi mv ${1}.$$ $1 shift done The awk script (simplified) - #! /usr/bin/awk -f /HHH.Web/{ if ( index($0,"Email") == 0) { sub(/HHH.Web/,"HHH.Web.Email"); } printf("%s\r\n",$0); next; } The command line find . -type f | xargs ~/scripts/run_parser.sh

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  • CPU-adaptive compression

    - by liori
    Hello, Let assume I need to send some data from one computer to another, over a pretty fast network... for example standard 100Mbit connection (~10MB/s). My disk drives are standard HDD, so their speed is somewhere between 30MB/s and 100MB/s. So I guess that compressing the data on the fly could help. But... I don't want to be limited by CPU. If I choose an algorithm that is intensive on CPU, the transfer will actually go slower than without compression. This is difficult with compressors like GZIP and BZIP2 because you usually set the compression strength once for the whole transfer, and my data streams are sometimes easy, sometimes hard to compress--this makes the process suboptimal because sometimes I do not use full CPU, and sometimes the bandwidth is underutilized. Is there a compression program that would adapt to current CPU/bandwidth and hit the sweet spot so that the transfer will be optimal? Ideally for Linux, but I am still curious about all solutions. I'd love to see something compatible with GZIP/BZIP2 decompressors, but this is not necessary. So I'd like to optimize total transfer time, not simply amount of bytes to send. Also I don't need real time decompression... real time compression is enough. The destination host can process the data later in its spare time. I know this doesn't change much (compression is usually much more CPU-intensive than decompression), but if there's a solution that could use this fact, all the better. Each time I am transferring different data, and I really want to make these one-time transfers as quick as possible. So I won't benefit from getting multiple transfers faster due to stronger compression. Thanks,

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  • How to disable apache mods without any problems

    - by Saif Bechan
    I have an apache installation where every single mod is enabled. I want my server to be as light as possible so I want to disable everything i do now need. What is the best way to go about this. I know its just removing the ; before the line in the conf file. But what if some hidden service somewhere need that at some random point in time. Can i get some suggestion on what to do.

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  • Optimize php-fpm and varnish for a powerfull server

    - by Jim
    My setup is: Intel® Core™ i7-2600 and RAM 16 GB DDR3 RAM varnish+nginx+php-fpm+apc for a not very heavy WordPress blog with W3 Total Cache and CDN My problem is that after 55 hits per second according to blitz.io varnish starts giving out timeouts. CPU usage at this time is hardly 1%. Free memory at all time remains 10GB+. I tried benchmarking php-fpm directly with result of 150hits/s without any timeouts. But after that the CPU usage goes 100% and it stops responding. Can you help me optimize it to handle more? As i understand nginx has nothing to do over here so i dont put its config. php-fpm config listen = /tmp/php5-fpm.sock listen.allowed_clients = 127.0.0.1 user = nginx group = nginx pm = dynamic pm.max_children = 150 pm.start_servers = 7 pm.min_spare_servers = 2 pm.max_spare_servers = 15 pm.max_requests = 500 slowlog = /var/log/php-fpm/www-slow.log php_admin_value[error_log] = /var/log/php-fpm/www-error.log php_admin_flag[log_errors] = on apc extension = apc.so apc.enabled=1 apc.shm_size=512MB apc.num_files_hint=0 apc.user_entries_hint=0 apc.ttl=7200 apc.use_request_time=1 apc.user_ttl=7200 apc.gc_ttl=3600 apc.cache_by_default=1 apc.filters apc.mmap_file_mask=/tmp/apc.XXXXXX apc.file_update_protection=2 apc.enable_cli=0 apc.max_file_size=1M apc.stat=1 apc.stat_ctime=0 apc.canonicalize=0 apc.write_lock=1 apc.report_autofilter=0 apc.rfc1867=0 apc.rfc1867_prefix =upload_ apc.rfc1867_name=APC_UPLOAD_PROGRESS apc.rfc1867_freq=0 apc.rfc1867_ttl=3600 apc.include_once_override=0 apc.lazy_classes=0 apc.lazy_functions=0 apc.coredump_unmap=0 apc.file_md5=0 apc.preload_path Varnish VCL backend default { .host = "127.0.0.1"; .port = "8080"; .connect_timeout = 6s; .first_byte_timeout = 6s; .between_bytes_timeout = 60s; } acl purgehosts { "localhost"; "127.0.0.1"; } # Called after a document has been successfully retrieved from the backend. sub vcl_fetch { # Uncomment to make the default cache "time to live" is 5 minutes, handy # but it may cache stale pages unless purged. (TODO) # By default Varnish will use the headers sent to it by Apache (the backend server) # to figure out the correct TTL. # WP Super Cache sends a TTL of 3 seconds, set in wp-content/cache/.htaccess set beresp.ttl = 24h; # Strip cookies for static files and set a long cache expiry time. if (req.url ~ "\.(jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|pdf|txt|tar|wav|bmp|rtf|js|flv|swf|html|htm)$") { unset beresp.http.set-cookie; set beresp.ttl = 24h; } # If WordPress cookies found then page is not cacheable if (req.http.Cookie ~"(wp-postpass|wordpress_logged_in|comment_author_)") { # set beresp.cacheable = false;#versions less than 3 #beresp.ttl>0 is cacheable so 0 will not be cached set beresp.ttl = 0s; } else { #set beresp.cacheable = true; set beresp.ttl=24h;#cache for 24hrs } # Varnish determined the object was not cacheable #if ttl is not > 0 seconds then it is cachebale if (!beresp.ttl > 0s) { # set beresp.http.X-Cacheable = "NO:Not Cacheable"; } else if ( req.http.Cookie ~"(wp-postpass|wordpress_logged_in|comment_author_)" ) { # You don't wish to cache content for logged in users set beresp.http.X-Cacheable = "NO:Got Session"; return(hit_for_pass); #previously just pass but changed in v3+ } else if ( beresp.http.Cache-Control ~ "private") { # You are respecting the Cache-Control=private header from the backend set beresp.http.X-Cacheable = "NO:Cache-Control=private"; return(hit_for_pass); } else if ( beresp.ttl < 1s ) { # You are extending the lifetime of the object artificially set beresp.ttl = 300s; set beresp.grace = 300s; set beresp.http.X-Cacheable = "YES:Forced"; } else { # Varnish determined the object was cacheable set beresp.http.X-Cacheable = "YES"; if (beresp.status == 404 || beresp.status >= 500) { set beresp.ttl = 0s; } # Deliver the content return(deliver); } sub vcl_hash { # Each cached page has to be identified by a key that unlocks it. # Add the browser cookie only if a WordPress cookie found. if ( req.http.Cookie ~"(wp-postpass|wordpress_logged_in|comment_author_)" ) { #set req.hash += req.http.Cookie; hash_data(req.http.Cookie); } } # vcl_recv is called whenever a request is received sub vcl_recv { # remove ?ver=xxxxx strings from urls so css and js files are cached. # Watch out when upgrading WordPress, need to restart Varnish or flush cache. set req.url = regsub(req.url, "\?ver=.*$", ""); # Remove "replytocom" from requests to make caching better. set req.url = regsub(req.url, "\?replytocom=.*$", ""); remove req.http.X-Forwarded-For; set req.http.X-Forwarded-For = client.ip; # Exclude this site because it breaks if cached if ( req.http.host == "sr.ituts.gr" ) { return( pass ); } # Serve objects up to 2 minutes past their expiry if the backend is slow to respond. set req.grace = 120s; # Strip cookies for static files: if (req.url ~ "\.(jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|pdf|txt|tar|wav|bmp|rtf|js|flv|swf|html|htm)$") { unset req.http.Cookie; return(lookup); } # Remove has_js and Google Analytics __* cookies. set req.http.Cookie = regsuball(req.http.Cookie, "(^|;\s*)(__[a-z]+|has_js)=[^;]*", ""); # Remove a ";" prefix, if present. set req.http.Cookie = regsub(req.http.Cookie, "^;\s*", ""); # Remove empty cookies. if (req.http.Cookie ~ "^\s*$") { unset req.http.Cookie; } if (req.request == "PURGE") { if (!client.ip ~ purgehosts) { error 405 "Not allowed."; } #previous version ban() was purge() ban("req.url ~ " + req.url + " && req.http.host == " + req.http.host); error 200 "Purged."; } # Pass anything other than GET and HEAD directly. if (req.request != "GET" && req.request != "HEAD") { return( pass ); } /* We only deal with GET and HEAD by default */ # remove cookies for comments cookie to make caching better. set req.http.cookie = regsub(req.http.cookie, "1231111111111111122222222333333=[^;]+(; )?", ""); # never cache the admin pages, or the server-status page, or your feed? you may want to..i don't if (req.request == "GET" && (req.url ~ "(wp-admin|bb-admin|server-status|feed)")) { return(pipe); } # don't cache authenticated sessions if (req.http.Cookie && req.http.Cookie ~ "(wordpress_|PHPSESSID)") { return(lookup); } # don't cache ajax requests if(req.http.X-Requested-With == "XMLHttpRequest" || req.url ~ "nocache" || req.url ~ "(control.php|wp-comments-post.php|wp-login.php|bb-login.php|bb-reset-password.php|register.php)") { return (pass); } return( lookup ); } Varnish Daemon options DAEMON_OPTS="-a :80 \ -T 127.0.0.1:6082 \ -f /etc/varnish/ituts.vcl \ -u varnish -g varnish \ -S /etc/varnish/secret \ -p thread_pool_add_delay=2 \ -p thread_pools=8 \ -p thread_pool_min=100 \ -p thread_pool_max=1000 \ -p session_linger=50 \ -p session_max=150000 \ -p sess_workspace=262144 \ -s malloc,5G" Im not sure where to start, should i for start optimize php-fpm and then go to varnish or php-fpm is at its max right now so i should start looking for the problem in varnish?

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  • Optimizing wireless router speed and minimizing interference.

    - by Tchalvak
    I've been experiencing problems with my wireless connectivity lately, and want to make sure that it's not related to the abundance of other wireless routers here in my building. So, what I'm looking for is a method (probably via some application or another) to audit the wireless channels (and other factors that might be important that I don't even know of yet) that are floating through the aether around me. Ubuntu or other linux apps are preferred, but some kind of windows/mac solution is possible, since I do have other OSes around me that I could install & test on. Router: netgear WGT624 v3 Hearsay tells me that channels 1, 6, and 11 are "non-overlapping" (I expect they aren't used for non-wireless-router purposes or something, not sure how they couldn't overlap with other routers using other channels), so perhaps my best choices of channel are limited, so if channels aren't really a big concern, I'd be happy to get links to other optimizations that I should look into.

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