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  • Visual Studio Little Wonders: Box Selection

    - by James Michael Hare
    So this week I decided I’d do a Little Wonder of a different kind and focus on an underused IDE improvement: Visual Studio’s Box Selection capability. This is a handy feature that many people still don’t realize was made available in Visual Studio 2010 (and beyond).  True, there have been other editors in the past with this capability, but now that it’s fully part of Visual Studio we can enjoy it’s goodness from within our own IDE. So, for those of you who don’t know what box selection is and what it allows you to do, read on! Sometimes, we want to select beyond the horizontal… The problem with traditional text selection in many editors is that it is horizontally oriented.  Sure, you can select multiple rows, but if you do you will pull in the entire row (at least for the middle rows).  Under the old selection scheme, if you wanted to select a portion of text from each row (a “box” of text) you were out of luck.  Box selection rectifies this by allowing you to select a box of text that bounded by a selection rectangle that you can grow horizontally or vertically.  So let’s think a situation that could occur where this comes in handy. Let’s say, for instance, that we are defining an enum in our code that we want to be able to translate into some string values (possibly to be stored in a database, output to screen, etc.). Perhaps such an enum would look like this: 1: public enum OrderType 2: { 3: Buy, // buy shares of a commodity 4: Sell, // sell shares of a commodity 5: Exchange, // exchange one commodity for another 6: Cancel, // cancel an order for a commodity 7: } 8:  Now, let’s say we are in the process of creating a Dictionary<K,V> to translate our OrderType: 1: var translator = new Dictionary<OrderType, string> 2: { 3: // do I really want to retype all this??? 4: }; Yes the example above is contrived so that we will pull some garbage if we do a multi-line select. I could select the lines above using the traditional multi-line selection: And then paste them into the translator code, which would result in this: 1: var translator = new Dictionary<OrderType, string> 2: { 3: Buy, // buy shares of a commodity 4: Sell, // sell shares of a commodity 5: Exchange, // exchange one commodity for another 6: Cancel, // cancel an order for a commodity 7: }; But I have a lot of junk there, sure I can manually clear it out, or use some search and replace magic, but if this were hundreds of lines instead of just a few that would quickly become cumbersome. The Box Selection Now that we have the ability to create box selections, we can select the box of text to delete!  Most of us are familiar with the fact we can drag the mouse (or hold [Shift] and use the arrow keys) to create a selection that can span multiple rows: Box selection, however, actually allows us to select a box instead of the typical horizontal lines: Then we can press the [delete] key and the pesky comments are all gone! You can do this either by holding down [Alt] while you select with your mouse, or by holding down [Alt+Shift] and using the arrow keys on the keyboard to grow the box horizontally or vertically. So now we have: 1: var translator = new Dictionary<OrderType, string> 2: { 3: Buy, 4: Sell, 5: Exchange, 6: Cancel, 7: }; Which is closer, but we still need an opening curly, the string to translate to, and the closing curly and comma. Fortunately, again, this is easy with box selections due to the fact box selection can even work for a zero-width selection! That is, hold down [Alt] and either drag down with no width, or hold down [Alt+Shift] and arrow down and you will define a selection range with no width, essentially, a vertical line selection: Notice the faint selection line on the right? So why is this useful? Well, just like with any selected range, we can type and it will replace the selection. What does this mean for box selections? It means that we can insert the same text all the way down on each line! If we have the same selection above, and type a curly and a space, we’d get: Imagine doing this over hundreds of lines and think of what a time saver it could be! Now make a zero-width selection on the other side: And type a curly and a comma, and we’d get: So close! Now finally, imagine we’ve already defined these strings somewhere and want to paste them in: 1: const private string BuyText = "Buy Shares"; 2: const private string SellText = "Sell Shares"; 3: const private string ExchangeText = "Exchange"; 4: const private string CancelText = "Cancel"; We can, again, use our box selection to pull out the constant names: And clicking copy (or [CTRL+C]) and then selecting a range to paste into: And finally clicking paste (or [CTRL+V]) to get the final result: 1: var translator = new Dictionary<OrderType, string> 2: { 3: { Buy, BuyText }, 4: { Sell, SellText }, 5: { Exchange, ExchangeText }, 6: { Cancel, CancelText }, 7: };   Sure, this was a contrived example, but I’m sure you’ll agree that it adds myriad possibilities of new ways to copy and paste vertical selections, as well as inserting text across a vertical slice. Summary: While box selection has been around in other editors, we finally get to experience it in VS2010 and beyond. It is extremely handy for selecting columns of information for cutting, copying, and pasting. In addition, it allows you to create a zero-width vertical insertion point that can be used to enter the same text across multiple rows. Imagine the time you can save adding repetitive code across multiple lines!  Try it, the more you use it, the more you’ll love it! Technorati Tags: C#,CSharp,.NET,Visual Studio,Little Wonders,Box Selection

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  • Is it worth caching a Dictionary for foreign key values in ASP.net?

    - by user169867
    I have a Dictionary<int, string> cached (for 20 minutes) that has ~120 ID/Name pairs for a reference table. I iterate over this collection when populating dropdown lists and I'm pretty sure this is faster than querying the DB for the full list each time. My question is more about if it makes sense to use this cached dictionary when displaying records that have a foreign key into this reference table. Say this cached reference table is a EmployeeType table. If I were to query and display a list of employee names and types should I query for EmployeeName and EmployeeTypeID and use my cached dictionary to grab the EmployeeTypeIDs name as each record is displayed or is it faster to just have the DB grab the EmployeeName and JOIN to get the EmployeeType string bypassing the cached Dictionary all together. I know both will work but I'm interested in what will perform the fastest. Thanks for any help.

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  • String.substring(index) has stoped my thread in debug mode.

    - by Arkaha
    Hello! I work with j2me polish 2.0.7, in eclipse 3.4.2, with wtk2.5.2_01. I create control which draws text: normal, bold, and italic. The code below is parsing raw text, and search for * and _ symbols, if found than add to draw vector the text and the drawer, and it's just stops after getting second time to the line 58: String test = new String(raw_text_buff.substring(iter)); it stops in raw_text_buff.substring(iter), ONLY in debug mode.. raw text is: bla bla bla *1000* bla bla Full code: private String raw_text = "bla bla bla *1000* bla bla"; Vector draw_items = null; private void prepareText() { char open_char = 0; int open_pos = 0; Object []param = null; StringBuffer sb = new StringBuffer(); String raw_text_buff = new String(raw_text); int iter = 0; boolean was_reset = false; while(true) { char c = raw_text_buff.charAt(iter); if(iter == raw_text_buff.length() || c == '*' || c == '_') { if(sb.length() > 0) { BmFont viewer = null; String str = sb.toString(); if(open_char == '*' && null != bm_strong) { viewer = bm_strong.getViewer(str); }else if(open_char == '_' && null != bm_italic) { viewer = bm_italic.getViewer(str); }else if(null != bm_normal) { viewer = bm_normal.getViewer(str); }else { } param = new Object[2]; param[0] = str; param[1] = viewer; if(null == draw_items) draw_items = new Vector(); draw_items.addElement(param); sb = new StringBuffer(); if(open_char == 0 && (c == '*' || c=='_')) open_char = c; else open_char = 0; String test = new String(raw_text_buff.substring(iter)); // stucks here. raw_text_buff = test; iter = 0; was_reset = true; }else { open_char = c; } if(iter == raw_text_buff.length()) break; }else { sb.append(c); } ++iter; } } What I'm doing wrong?

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  • MySQL query, 2 similar servers, 2 minute difference in execution times

    - by mr12086
    I had a similar question on stack overflow, but it seems to be more server/mysql setup related than coding. The queries below all execute instantly on our development server where as they can take upto 2 minutes 20 seconds. The query execution time seems to be affected by home ambiguous the LIKE string's are. If they closely match a country that has few matches it will take less time, and if you use something like 'ge' for germany - it will take longer to execute. But this doesn't always work out like that, at times its quite erratic. Sending data appears to be the culprit but why and what does that mean. Also memory on production looks to be quite low (free memory)? Production: Intel Quad Xeon E3-1220 3.1GHz 4GB DDR3 2x 1TB SATA in RAID1 Network speed 100Mb Ubuntu Development Intel Core i3-2100, 2C/4T, 3.10GHz 500 GB SATA - No RAID 4GB DDR3 UPDATE 2 : mysqltuner output: [prod] -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.1.61-0ubuntu0.10.04.1 [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: +Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in MyISAM tables: 103M (Tables: 180) [--] Data in InnoDB tables: 491M (Tables: 19) [!!] Total fragmented tables: 38 -------- Security Recommendations ------------------------------------------- [OK] All database users have passwords assigned -------- Performance Metrics ------------------------------------------------- [--] Up for: 77d 4h 6m 1s (53M q [7.968 qps], 14M conn, TX: 87B, RX: 12B) [--] Reads / Writes: 98% / 2% [--] Total buffers: 58.0M global + 2.7M per thread (151 max threads) [OK] Maximum possible memory usage: 463.8M (11% of installed RAM) [OK] Slow queries: 0% (12K/53M) [OK] Highest usage of available connections: 22% (34/151) [OK] Key buffer size / total MyISAM indexes: 16.0M/10.6M [OK] Key buffer hit rate: 98.7% (162M cached / 2M reads) [OK] Query cache efficiency: 20.7% (7M cached / 36M selects) [!!] Query cache prunes per day: 3934 [OK] Sorts requiring temporary tables: 1% (3K temp sorts / 230K sorts) [!!] Joins performed without indexes: 71068 [OK] Temporary tables created on disk: 24% (3M on disk / 13M total) [OK] Thread cache hit rate: 99% (690 created / 14M connections) [!!] Table cache hit rate: 0% (64 open / 85M opened) [OK] Open file limit used: 12% (128/1K) [OK] Table locks acquired immediately: 99% (16M immediate / 16M locks) [!!] InnoDB data size / buffer pool: 491.9M/8.0M -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance Enable the slow query log to troubleshoot bad queries Adjust your join queries to always utilize indexes Increase table_cache gradually to avoid file descriptor limits Variables to adjust: query_cache_size (> 16M) join_buffer_size (> 128.0K, or always use indexes with joins) table_cache (> 64) innodb_buffer_pool_size (>= 491M) [dev] -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.1.62-0ubuntu0.11.10.1 [!!] Switch to 64-bit OS - MySQL cannot currently use all of your RAM -------- Storage Engine Statistics ------------------------------------------- [--] Status: +Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in MyISAM tables: 185M (Tables: 632) [--] Data in InnoDB tables: 967M (Tables: 38) [!!] Total fragmented tables: 73 -------- Security Recommendations ------------------------------------------- [OK] All database users have passwords assigned -------- Performance Metrics ------------------------------------------------- [--] Up for: 1d 2h 26m 9s (5K q [0.058 qps], 1K conn, TX: 4M, RX: 1M) [--] Reads / Writes: 99% / 1% [--] Total buffers: 58.0M global + 2.7M per thread (151 max threads) [OK] Maximum possible memory usage: 463.8M (11% of installed RAM) [OK] Slow queries: 0% (0/5K) [OK] Highest usage of available connections: 1% (2/151) [OK] Key buffer size / total MyISAM indexes: 16.0M/18.6M [OK] Key buffer hit rate: 99.9% (60K cached / 36 reads) [OK] Query cache efficiency: 44.5% (1K cached / 2K selects) [OK] Query cache prunes per day: 0 [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 44 sorts) [OK] Temporary tables created on disk: 24% (162 on disk / 666 total) [OK] Thread cache hit rate: 99% (2 created / 1K connections) [!!] Table cache hit rate: 1% (64 open / 4K opened) [OK] Open file limit used: 8% (88/1K) [OK] Table locks acquired immediately: 100% (1K immediate / 1K locks) [!!] InnoDB data size / buffer pool: 967.7M/8.0M -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance Enable the slow query log to troubleshoot bad queries Increase table_cache gradually to avoid file descriptor limits Variables to adjust: table_cache (> 64) innodb_buffer_pool_size (>= 967M) UPDATE 1: When testing the queries listed here there is usually no more than one other query taking place, and usually none. Because production is actually handling apache requests that development gets very few of as it's only myself and 1 other who accesses it - could the 4GB of RAM be getting exhausted by using the single machine for both apache and mysql server? Production: sudo hdparm -tT /dev/sda /dev/sda: Timing cached reads: 24872 MB in 2.00 seconds = 12450.72 MB/sec Timing buffered disk reads: 368 MB in 3.00 seconds = 122.49 MB/sec sudo hdparm -tT /dev/sdb /dev/sdb: Timing cached reads: 24786 MB in 2.00 seconds = 12407.22 MB/sec Timing buffered disk reads: 350 MB in 3.00 seconds = 116.53 MB/sec Server version(mysql + ubuntu versions): 5.1.61-0ubuntu0.10.04.1 Development: sudo hdparm -tT /dev/sda /dev/sda: Timing cached reads: 10632 MB in 2.00 seconds = 5319.40 MB/sec Timing buffered disk reads: 400 MB in 3.01 seconds = 132.85 MB/sec Server version(mysql + ubuntu versions): 5.1.62-0ubuntu0.11.10.1 ORIGINAL DATA : This query is NOT the query in question but is related so ill post it. SELECT f.form_question_has_answer_id FROM form_question_has_answer f INNER JOIN project_company_has_user p ON f.form_question_has_answer_user_id = p.project_company_has_user_user_id INNER JOIN company c ON p.project_company_has_user_company_id = c.company_id INNER JOIN project p2 ON p.project_company_has_user_project_id = p2.project_id INNER JOIN user u ON p.project_company_has_user_user_id = u.user_id INNER JOIN form f2 ON p.project_company_has_user_project_id = f2.form_project_id WHERE (f2.form_template_name = 'custom' AND p.project_company_has_user_garbage_collection = 0 AND p.project_company_has_user_project_id = '29') AND (LCASE(c.company_country) LIKE '%ge%' OR LCASE(c.company_country) LIKE '%abcde%') AND f.form_question_has_answer_form_id = '174' And the explain plan for the above query is, run on both dev and production produce the same plan. +----+-------------+-------+--------+----------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+----------------------------------------------------+------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+--------+----------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+----------------------------------------------------+------+-------------+ | 1 | SIMPLE | p2 | const | PRIMARY | PRIMARY | 4 | const | 1 | Using index | | 1 | SIMPLE | f | ref | form_question_has_answer_form_id,form_question_has_answer_user_id | form_question_has_answer_form_id | 4 | const | 796 | Using where | | 1 | SIMPLE | u | eq_ref | PRIMARY | PRIMARY | 4 | new_klarents.f.form_question_has_answer_user_id | 1 | Using index | | 1 | SIMPLE | p | ref | project_company_has_user_unique_key,project_company_has_user_user_id,project_company_has_user_company_id,project_company_has_user_project_id | project_company_has_user_user_id | 4 | new_klarents.f.form_question_has_answer_user_id | 1 | Using where | | 1 | SIMPLE | f2 | ref | form_project_id | form_project_id | 4 | const | 15 | Using where | | 1 | SIMPLE | c | eq_ref | PRIMARY | PRIMARY | 4 | new_klarents.p.project_company_has_user_company_id | 1 | Using where | +----+-------------+-------+--------+----------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+----------------------------------------------------+------+-------------+ This query takes 2 minutes ~20 seconds to execute. The query that is ACTUALLY being run on the server is this one: SELECT COUNT(*) AS num_results FROM (SELECT f.form_question_has_answer_id FROM form_question_has_answer f INNER JOIN project_company_has_user p ON f.form_question_has_answer_user_id = p.project_company_has_user_user_id INNER JOIN company c ON p.project_company_has_user_company_id = c.company_id INNER JOIN project p2 ON p.project_company_has_user_project_id = p2.project_id INNER JOIN user u ON p.project_company_has_user_user_id = u.user_id INNER JOIN form f2 ON p.project_company_has_user_project_id = f2.form_project_id WHERE (f2.form_template_name = 'custom' AND p.project_company_has_user_garbage_collection = 0 AND p.project_company_has_user_project_id = '29') AND (LCASE(c.company_country) LIKE '%ge%' OR LCASE(c.company_country) LIKE '%abcde%') AND f.form_question_has_answer_form_id = '174' GROUP BY f.form_question_has_answer_id;) dctrn_count_query; With explain plans (again same on dev and production): +----+-------------+-------+--------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+----------------------------------------------------+------+------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+--------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+----------------------------------------------------+------+------------------------------+ | 1 | PRIMARY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | Select tables optimized away | | 2 | DERIVED | p2 | const | PRIMARY | PRIMARY | 4 | | 1 | Using index | | 2 | DERIVED | f | ref | form_question_has_answer_form_id,form_question_has_answer_user_id | form_question_has_answer_form_id | 4 | | 797 | Using where | | 2 | DERIVED | p | ref | project_company_has_user_unique_key,project_company_has_user_user_id,project_company_has_user_company_id,project_company_has_user_project_id,project_company_has_user_garbage_collection | project_company_has_user_user_id | 4 | new_klarents.f.form_question_has_answer_user_id | 1 | Using where | | 2 | DERIVED | f2 | ref | form_project_id | form_project_id | 4 | | 15 | Using where | | 2 | DERIVED | c | eq_ref | PRIMARY | PRIMARY | 4 | new_klarents.p.project_company_has_user_company_id | 1 | Using where | | 2 | DERIVED | u | eq_ref | PRIMARY | PRIMARY | 4 | new_klarents.p.project_company_has_user_user_id | 1 | Using where; Using index | +----+-------------+-------+--------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+----------------------------------------------------+------+------------------------------+ On the production server the information I have is as follows. Upon execution: +-------------+ | num_results | +-------------+ | 3 | +-------------+ 1 row in set (2 min 14.28 sec) Show profile: +--------------------------------+------------+ | Status | Duration | +--------------------------------+------------+ | starting | 0.000016 | | checking query cache for query | 0.000057 | | Opening tables | 0.004388 | | System lock | 0.000003 | | Table lock | 0.000036 | | init | 0.000030 | | optimizing | 0.000016 | | statistics | 0.000111 | | preparing | 0.000022 | | executing | 0.000004 | | Sorting result | 0.000002 | | Sending data | 136.213836 | | end | 0.000007 | | query end | 0.000002 | | freeing items | 0.004273 | | storing result in query cache | 0.000010 | | logging slow query | 0.000001 | | logging slow query | 0.000002 | | cleaning up | 0.000002 | +--------------------------------+------------+ On development the results are as follows. +-------------+ | num_results | +-------------+ | 3 | +-------------+ 1 row in set (0.08 sec) Again the profile for this query: +--------------------------------+----------+ | Status | Duration | +--------------------------------+----------+ | starting | 0.000022 | | checking query cache for query | 0.000148 | | Opening tables | 0.000025 | | System lock | 0.000008 | | Table lock | 0.000101 | | optimizing | 0.000035 | | statistics | 0.001019 | | preparing | 0.000047 | | executing | 0.000008 | | Sorting result | 0.000005 | | Sending data | 0.086565 | | init | 0.000015 | | optimizing | 0.000006 | | executing | 0.000020 | | end | 0.000004 | | query end | 0.000004 | | freeing items | 0.000028 | | storing result in query cache | 0.000005 | | removing tmp table | 0.000008 | | closing tables | 0.000008 | | logging slow query | 0.000002 | | cleaning up | 0.000005 | +--------------------------------+----------+ If i remove user and/or project innerjoins the query is reduced to 30s. Last bit of information I have: Mysqlserver and Apache are on the same box, there is only one box for production. Production output from top: before & after. top - 15:43:25 up 78 days, 12:11, 4 users, load average: 1.42, 0.99, 0.78 Tasks: 162 total, 2 running, 160 sleeping, 0 stopped, 0 zombie Cpu(s): 0.1%us, 50.4%sy, 0.0%ni, 49.5%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 4037868k total, 3772580k used, 265288k free, 243704k buffers Swap: 3905528k total, 265384k used, 3640144k free, 1207944k cached top - 15:44:31 up 78 days, 12:13, 4 users, load average: 1.94, 1.23, 0.87 Tasks: 160 total, 2 running, 157 sleeping, 0 stopped, 1 zombie Cpu(s): 0.2%us, 50.6%sy, 0.0%ni, 49.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 4037868k total, 3834300k used, 203568k free, 243736k buffers Swap: 3905528k total, 265384k used, 3640144k free, 1207804k cached But this isn't a good representation of production's normal status so here is a grab of it from today outside of executing the queries. top - 11:04:58 up 79 days, 7:33, 4 users, load average: 0.39, 0.58, 0.76 Tasks: 156 total, 1 running, 155 sleeping, 0 stopped, 0 zombie Cpu(s): 3.3%us, 2.8%sy, 0.0%ni, 93.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 4037868k total, 3676136k used, 361732k free, 271480k buffers Swap: 3905528k total, 268736k used, 3636792k free, 1063432k cached Development: This one doesn't change during or after. top - 15:47:07 up 110 days, 22:11, 7 users, load average: 0.17, 0.07, 0.06 Tasks: 210 total, 2 running, 208 sleeping, 0 stopped, 0 zombie Cpu(s): 0.1%us, 0.2%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 4111972k total, 1821100k used, 2290872k free, 238860k buffers Swap: 4183036k total, 66472k used, 4116564k free, 921072k cached

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  • SQL Server connection help...

    - by Gopal
    Using SQL Server 2005 I have the server connection name as (server1) in windows authentication mode, I want to change windows authentication mode to sql server authentication mode... when i try to change sql server authentication mode with username = sa & password = sa, it showing error... How to change the authentication mode or how to create a new sql connection?

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  • Hide the Emacs echo area when not in use

    - by Baldur
    The echo area is the line at the bottom of Emacs below the mode line: ~ ~ | | +-----------------------+ |-U:--- mode-line | +-----------------------+ | M-x echo-area | +-----------------------+ Now the mode line is highly customizable while the echo area is more rigid (and unused a lot of the time). The question is pretty simple: is it possible to hide the echo area during inactivity and redisplay it once it needs your attention: ~ ~ ~ ~ | | | | | | +-----------------------+ | | |-U:--- mode-line | +-----------------------+ +-----------------------+ |-U:--- mode-line | | M-x echo-area | +-----------------------+ +-----------------------+ Inactive Active This is similar to the way Google Chrome displays URLs when you hover your mose over a link and the Firefox addon Pentadactyl where the command-line is hidden by default.

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  • SQL SERVER – Data Pages in Buffer Pool – Data Stored in Memory Cache

    - by pinaldave
    This will drop all the clean buffers so we will be able to start again from there. Now, run the following script and check the execution plan of the query. Have you ever wondered what types of data are there in your cache? During SQL Server Trainings, I am usually asked if there is any way one can know how much data in a table is stored in the memory cache? The more detailed question I usually get is if there are multiple indexes on table (and used in a query), were the data of the single table stored multiple times in the memory cache or only for a single time? Here is a query you can run to figure out what kind of data is stored in the cache. USE AdventureWorks GO SELECT COUNT(*) AS cached_pages_count, name AS BaseTableName, IndexName, IndexTypeDesc FROM sys.dm_os_buffer_descriptors AS bd INNER JOIN ( SELECT s_obj.name, s_obj.index_id, s_obj.allocation_unit_id, s_obj.OBJECT_ID, i.name IndexName, i.type_desc IndexTypeDesc FROM ( SELECT OBJECT_NAME(OBJECT_ID) AS name, index_id ,allocation_unit_id, OBJECT_ID FROM sys.allocation_units AS au INNER JOIN sys.partitions AS p ON au.container_id = p.hobt_id AND (au.type = 1 OR au.type = 3) UNION ALL SELECT OBJECT_NAME(OBJECT_ID) AS name, index_id, allocation_unit_id, OBJECT_ID FROM sys.allocation_units AS au INNER JOIN sys.partitions AS p ON au.container_id = p.partition_id AND au.type = 2 ) AS s_obj LEFT JOIN sys.indexes i ON i.index_id = s_obj.index_id AND i.OBJECT_ID = s_obj.OBJECT_ID ) AS obj ON bd.allocation_unit_id = obj.allocation_unit_id WHERE database_id = DB_ID() GROUP BY name, index_id, IndexName, IndexTypeDesc ORDER BY cached_pages_count DESC; GO Now let us run the query above and observe the output of the same. We can see in the above query that there are four columns. Cached_Pages_Count lists the pages cached in the memory. BaseTableName lists the original base table from which data pages are cached. IndexName lists the name of the index from which pages are cached. IndexTypeDesc lists the type of index. Now, let us do one more experience here. Please note that you should not run this test on a production server as it can extremely reduce the performance of the database. DBCC DROPCLEANBUFFERS This will drop all the clean buffers and we will be able to start again from there. Now run following script and check the execution plan for the same. USE AdventureWorks GO SELECT UnitPrice, ModifiedDate FROM Sales.SalesOrderDetail WHERE SalesOrderDetailID BETWEEN 1 AND 100 GO The execution plans contain the usage of two different indexes. Now, let us run the script that checks the pages cached in SQL Server. It will give us the following output. It is clear from the Resultset that when more than one index is used, datapages related to both or all of the indexes are stored in Memory Cache separately. Let me know what you think of this article. I had a great pleasure while writing this article because I was able to write on this subject, which I like the most. In the next article, we will exactly see what data are cached and those that are not cached, using a few undocumented commands. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: DMV, Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL DMV

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  • Page output caching for dynamic web applications

    - by Mike Ellis
    I am currently working on a web application where the user steps (forward or back) through a series of pages with "Next" and "Previous" buttons, entering data until they reach a page with the "Finish" button. Until finished, all data is stored in Session state, then sent to the mainframe database via web services at the end of the process. Some of the pages display data from previous pages in order to collect additional information. These pages can never be cached because they are different for every user. For pages that don't display this dynamic data, they can be cached, but only the first time they load. After that, the data that was previously entered needs to be displayed. This requires Page_Load to fire, which means the page can't be cached at that point. A couple of weeks ago, I knew almost nothing about implementing page caching. Now I still don't know much, but I know a little bit, and here is the solution that I developed with the help of others on my team and a lot of reading and trial-and-error. We have a base page class defined from which all pages inherit. In this class I have defined a method that sets the caching settings programmatically. For pages that can be cached, they call this base page method in their Page_Load event within a if(!IsPostBack) block, which ensures that only the page itself gets cached, not the data on the page. if(!IsPostBack) {     ...     SetCacheSettings();     ... } protected void SetCacheSettings() {     Response.Cache.AddValidationCallback(new HttpCacheValidateHandler(Validate), null);     Response.Cache.SetExpires(DateTime.Now.AddHours(1));     Response.Cache.SetSlidingExpiration(true);     Response.Cache.SetValidUntilExpires(true);     Response.Cache.SetCacheability(HttpCacheability.ServerAndNoCache); } The AddValidationCallback sets up an HttpCacheValidateHandler method called Validate which runs logic when a cached page is requested. The Validate method signature is standard for this method type. public static void Validate(HttpContext context, Object data, ref HttpValidationStatus status) {     string visited = context.Request.QueryString["v"];     if (visited != null && "1".Equals(visited))     {         status = HttpValidationStatus.IgnoreThisRequest; //force a page load     }     else     {         status = HttpValidationStatus.Valid; //load from cache     } } I am using the HttpValidationStatus values IgnoreThisRequest or Valid which forces the Page_Load event method to run or allows the page to load from cache, respectively. Which one is set depends on the value in the querystring. The value in the querystring is set up on each page in the "Next" and "Previous" button click event methods based on whether the page that the button click is taking the user to has any data on it or not. bool hasData = HasPageBeenVisited(url); if (hasData) {     url += VISITED; } Response.Redirect(url); The HasPageBeenVisited method determines whether the destination page has any data on it by checking one of its required data fields. (I won't include it here because it is very system-dependent.) VISITED is a string constant containing "?v=1" and gets appended to the url if the destination page has been visited. The reason this logic is within the "Next" and "Previous" button click event methods is because 1) the Validate method is static which doesn't allow it to access non-static data such as the data fields for a particular page, and 2) at the time at which the Validate method runs, either the data has not yet been deserialized from Session state or is not available (different AppDomain?) because anytime I accessed the Session state information from the Validate method, it was always empty.

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  • Automount of external hard disk

    - by moose
    I have an Intenso 6002560 1TB Memory Station - an external hard disk. This hard disk gets connected via Y-USB cable. When I connect both USB-ends to my Notebook, it gets recognized by my Ubuntu 10.04.4 LTS system: moose@pc07:~$ lsusb [...] Bus 002 Device 005: ID 13fd:1840 Initio Corporation [...] and Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00065e10 Device Boot Start End Blocks Id System /dev/sda1 * 1 37810 303704064 83 Linux /dev/sda2 37810 38914 8864769 5 Extended /dev/sda5 37810 38914 8864768 82 Linux swap / Solaris Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0d6ea32a Device Boot Start End Blocks Id System /dev/sdc1 1 121601 976759008+ c W95 FAT32 (LBA) But it did not get mounted: moose@pc07:/dev$ mount -l /dev/sda1 on / type ext4 (rw,errors=remount-ro,user_xattr) proc on /proc type proc (rw,noexec,nosuid,nodev) none on /sys type sysfs (rw,noexec,nosuid,nodev) none on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) none on /dev type devtmpfs (rw,mode=0755) none on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) none on /dev/shm type tmpfs (rw,nosuid,nodev) none on /var/run type tmpfs (rw,nosuid,mode=0755) none on /var/lock type tmpfs (rw,noexec,nosuid,nodev) none on /lib/init/rw type tmpfs (rw,nosuid,mode=0755) binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev) gvfs-fuse-daemon on /home/moose/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=moose) However, I could mount it manually with mount -t vfat /dev/sdc1 /mnt/sdc1 as you can see here: moose@pc07:~$ mount -l /dev/sda1 on / type ext4 (rw,errors=remount-ro,user_xattr) proc on /proc type proc (rw,noexec,nosuid,nodev) none on /sys type sysfs (rw,noexec,nosuid,nodev) none on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) none on /dev type devtmpfs (rw,mode=0755) none on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) none on /dev/shm type tmpfs (rw,nosuid,nodev) none on /var/run type tmpfs (rw,nosuid,mode=0755) none on /var/lock type tmpfs (rw,noexec,nosuid,nodev) none on /lib/init/rw type tmpfs (rw,nosuid,mode=0755) binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev) gvfs-fuse-daemon on /home/moose/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=moose) /dev/sdc1 on /mnt/sdc1 type vfat (rw) edit: Another command: moose@pc07:~$ sudo blkid -o list device fs_type label mount point UUID ---------------------------------------------------------------------------------------------------------------------- /dev/sda1 ext4 / 45eb611b-517e-425b-8057-0391726cccd5 /dev/sda5 swap <swap> e9dc42f3-594c-4b62-874a-305eda5eed41 moose@pc07:~$ blkid -o list device fs_type label mount point UUID ---------------------------------------------------------------------------------------------------------------------- /dev/sda1 ext4 / 45eb611b-517e-425b-8057-0391726cccd5 /dev/sda5 swap <swap> e9dc42f3-594c-4b62-874a-305eda5eed41 /dev/sdc1 /mnt/sdc1 edit: another command: moose@pc07:~$ ls -l /dev/disk/by-uuid/ total 0 lrwxrwxrwx 1 root root 10 2012-09-30 09:31 45eb611b-517e-425b-8057-0391726cccd5 -> ../../sda1 lrwxrwxrwx 1 root root 10 2012-09-30 09:31 e9dc42f3-594c-4b62-874a-305eda5eed41 -> ../../sda5 Here is a link to a Launchpad question about this problem. But I would like it to mount automatically. What do I have to do?

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  • Using Oracle Linux iSCSI targets with Oracle VM

    - by wim.coekaerts
    A few days ago I had written a blog entry on how to use Oracle Solaris 10 (in my case), ZFS and the iSCSI target feature in Oracle Solaris to create a set of devices exported to my Oracle VM server. Oracle Linux can do this as well and I wanted to make sure I also tried out how to do this on Oracle Linux and here are the results. When you install Oracle Linux 5 update 5 (anything newer than update 3), it comes with an rpm called scsi-target-utils. To begin your quest, should you choose to accept it :) make sure this is installed. rpm -qa |grep scsi-target If it is not installed : up2date scsi-target-utils The target utils come with a tool tgtadm which is similar to iscsitadm on Oracle Solaris. There are 2 components again on the iSCSI server side. (1) create volumes - we will use lvm with lvcreate (2) expose a target using tgtadm. My server has a simple setup. All the disks are part of a single volume group called vgroot. To export a 50Gb volume I just create a new volume : lvcreate -L 50G -nmytest1 vgroot This will show up as a new volume in /dev/mapper as /dev/mapper/vgroot-mytest1. Create as many as you want for your environment. Since I already have my blog entry about the 5 volumes, I am not going to repeat the whole thing. You can just go look at the previous blog entry. Now that we have created the volume, we need to use tgtadm to set it up : make sure the service is running : /etc/init.d/tgtd start or service tgtd start (if you want to keep it running you can do chkconfig tgtd on to start it automatically at boottime) Next you need a targetname to set everything up. My recommendation would be to install iscsi-initiator-utils . This will create an iscsi id and put it in /etc/iscsi/initiatorname.iscsi. For convenience you can do : source /etc/iscsi/initiatorname.iscsi echo $InitiatorName and from here on use $InitiatorName instead of the long complex iqn. create your target : tgtadm --lld iscsi --op new --mode target --tid 1 -T $InitiatorName to show the status : tgtadm --lld iscsi --op show --mode target add the volume previously created : tgtadm --lld iscsi --op new --mode logicalunit --tid 1 --lun 1 -b /dev/mapper/vgroot-mytest1 re-run status to see it's there : tgtadm --lld iscsi --op show --mode target and just like on Oracle Solaris you now have to export (bind) it : tgtadm --lld iscsi --op bind --mode target --tid 1 -I iqn.1986-03.com.sun:01:2a7526f0ffff If you want to export the lun to every iscsi initiator then replace the iqn with ALL. Of course you have to add the iqn of each iscsi initiator or client you want to connect. In the case of my 2 node Oracle VM server setup, both Oracle VM server's initiator names would have to be added. use status again to see that it has this iqn under ACL tgtadm --lld iscsi --op show --mode target You can drop the --lld iscsi if you want, or alias it. It just makes the command line more obvious as to what you are doing. Oracle VM side : Refer back to the previous blog entry for the detailed setup of my Oracle VM server volumes but the exact same commands will be used there. discover : iscsiadm --mode discovery --type sendtargets --portal login : iscsiadm --mode node --targetname iscsi targetname --portal --login get devices : /etc/init.d/iscsi restart and voila you should be in business. have fun.

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  • "previousMode": Controling the Pin Action of a TopComponent

    - by Geertjan
    An excellent thing I learned today is that you, as a developer of a NetBeans module or NetBeans Platform application, can control the pin button. Up until today, whenever I had a TopComponent defined to appear in "rightSlidingSide" mode and then I clicked the "pin" button, as shown here... ...the TopComponent would then find itself pinned in the "explorer" mode. Would make more sense if it would be pinned in the "properties" mode, which is the docked mode closest to the "rightSlidingSide" mode. Not being able to control the "pin" button has been a recurring question (including in my own head) over several years. But the NetBeans Team's window system guru Stan Aubrecht informed me today that a "previousMode" attribute exists in the "tc-ref" file of the TopComponent. Since a few releases, that file is generated via the annotations in the TopComponent. However, "previousMode" is currently not one of the attributes exposed by the @TopComponent.Registration annotation. Therefore, what I did was this: Set "rightSlidingSide" in the "mode" attribute of the @TopComponent.Registration. Build the module. Find the "generated-layer.xml" (in the Files window) and move the layer registration of the TopComponent, including its action and menu item for opening the TopComponent, into my own manual layer within the module. Then remove all the TopComponent annotations from the TopComponent, though you can keep @ConvertAsProperties and @Messages. Then add the "previousMode" attribute, as highlighted below, into my own layer file, i.e., within the tags copied from the "generated-layer.xml": <folder name="Modes"> <folder name="rightSlidingSide"> <file name="ComparatorTopComponent.wstcref"> <![CDATA[<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE tc-ref PUBLIC "-//NetBeans//DTD Top Component in Mode Properties 2.0//EN" "http://www.netbeans.org/dtds/tc-ref2_0.dtd"> <tc-ref version="2.0"> <tc-id id="ComparatorTopComponent"/> <state opened="false"/> <previousMode name="properties" index="0" /> </tc-ref> ]]> </file> </folder> </folder> Now when you run the application and pin the specific TopComponent defined above, i.e., in the above case, named "ComparatorTopComponent", you will find it is pinned into the "properties" mode! That's pretty cool and if you agree, then you're a pretty cool NetBeans Platform developer, and I'd love to find out more about the application/s you're creating on the NetBeans Platform! Meanwhile, I'm going to create an issue for exposing the "previousMode" attribute in the @TopComponent.Registration annotation.

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  • ?Linux 6???UDEV??RAC ASM???????

    - by Liu Maclean(???)
    Maclean?????UDEV??ASMLIB?RAC???????????,???????????????????:Why ASMLIB and why not???UDEV????RAC ASM?????  ?«??UDEV????RAC ASM????? »???????????????,????????udev rule????: for i in b c d e f g h i j k ; do echo "KERNEL==\"sd*\", BUS==\"scsi\", PROGRAM==\"/sbin/scsi_id -g -u -s %p\", RESULT==\"`scsi_id -g -u -s /block/sd$i`\", NAME=\"asm-disk$i\", OWNER=\"grid\", GROUP=\"asmadmin\", MODE=\"0660\"" done ?????Linux 5?????, ????????redhat/Oracle Linux 6???????????? ????: ?OEL6??RHEL6?,????????? ??????:1. scsi_id??????????,scsi_id -g -u -s??????????2. udevtest???????,????udevadm??How to use udev for Oracle ASM in Oracle Linux 6   ???????????,???redhat/Oracle Linux 6??????udev rule ????: 1. #????? Linux 6.0???? [root@vrh6 dev]# cat /etc/issue Oracle Linux Server release 6.2 Kernel \r on an \m 2. #?????/etc/scsi_id.config echo "options=--whitelisted --replace-whitespace" >> /etc/scsi_id.config 3. #?????????udev?? [root@vrh6 dev]# ls -l sd* brw-rw----. 1 root disk 8, 0 Jun 30 09:29 sda brw-rw----. 1 root disk 8, 1 Jun 30 09:29 sda1 brw-rw----. 1 root disk 8, 2 Jun 30 09:29 sda2 brw-rw----. 1 root disk 8, 16 Jun 30 09:29 sdb brw-rw----. 1 root disk 8, 32 Jun 30 09:29 sdc brw-rw----. 1 root disk 8, 48 Jun 30 09:29 sdd brw-rw----. 1 root disk 8, 64 Jun 30 09:29 sde brw-rw----. 1 root disk 8, 80 Jun 30 09:29 sdf ??????? sdb-> sdf???????? 4. ? b->f?????for ???,??: # AUTO UDEV RULE BY Maclean Liu 2012/06/30 for i in b c d e f ; do echo "KERNEL==\"sd*\", BUS==\"scsi\", PROGRAM==\"/sbin/scsi_id --whitelisted --replace-whitespace --device=/dev/\$name\", RESULT==\"`/sbin/scsi_id --whitelisted --replace-whitespace --device=/dev/sd$i`\", NAME=\"asm-disk$i\", OWNER=\"grid\", GROUP=\"asmadmin\", MODE=\"0660\"" done ????sdb->sdf ?????RULE,????RULE???/etc/udev/rules.d/99-oracle-asmdevices.rules? ??????????? ,??RULE?99-oracle-asmdevices.rules # AUTO UDEV RULE BY Maclean Liu 2012/06/30 for i in b c d e f ; do echo "KERNEL==\"sd*\", BUS==\"scsi\", PROGRAM==\"/sbin/scsi_id --whitelisted --replace-whitespace --device=/dev/\$name\", RESULT==\"`/sbin/scsi_id --whitelisted --replace-whitespace --device=/dev/sd$i`\", NAME=\"asm-disk$i\", OWNER=\"grid\", GROUP=\"asmadmin\", MODE=\"0660\"" >> /etc/udev/rules.d/99-oracle-asmdevices.rules done 5. ?????root??/sbin/start_udev ?? ??????: [root@vrh6 dev]# echo "options=--whitelisted --replace-whitespace" >> /etc/scsi_id.config [root@vrh6 dev]# for i in b c d e f ; > do > echo "KERNEL==\"sd*\", BUS==\"scsi\", PROGRAM==\"/sbin/scsi_id --whitelisted --replace-whitespace --device=/dev/\$name\", RESULT==\"`/sbin/scsi_id --whitelisted --replace-whitespace --device=/dev/sd$i`\", NAME=\"asm-disk$i\", OWNER=\"grid\", GROUP=\"asmadmin\", MODE=\"0660\"" >> /etc/udev/rules.d/99-oracle-asmdevices.rules > done [root@vrh6 dev]# [root@vrh6 dev]# cat /etc/udev/rules.d/99-oracle-asmdevices.rules KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="1ATA_VBOX_HARDDISK_VB09cadb31-cfbea255", NAME="asm-diskb", OWNER="grid", GROUP="asmadmin", MODE="0660" KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="1ATA_VBOX_HARDDISK_VB5f097069-59efb82f", NAME="asm-diskc", OWNER="grid", GROUP="asmadmin", MODE="0660" KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="1ATA_VBOX_HARDDISK_VB4e1a81c0-20478bc4", NAME="asm-diskd", OWNER="grid", GROUP="asmadmin", MODE="0660" KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="1ATA_VBOX_HARDDISK_VBdcce9285-b13c5a27", NAME="asm-diske", OWNER="grid", GROUP="asmadmin", MODE="0660" KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="1ATA_VBOX_HARDDISK_VB82effe1a-dbca7dff", NAME="asm-diskf", OWNER="grid", GROUP="asmadmin", MODE="0660" [root@vrh6 dev]# [root@vrh6 dev]# /sbin/start_udev Starting udev: [ OK ] [root@vrh6 dev]# ls -l asm* brw-rw----. 1 grid asmadmin 8, 16 Jun 30 09:34 asm-diskb brw-rw----. 1 grid asmadmin 8, 32 Jun 30 09:34 asm-diskc brw-rw----. 1 grid asmadmin 8, 48 Jun 30 09:34 asm-diskd brw-rw----. 1 grid asmadmin 8, 64 Jun 30 09:34 asm-diske brw-rw----. 1 grid asmadmin 8, 80 Jun 30 09:34 asm-diskf

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  • Why has my computer started to make noises when I turn it on after I put it into sleep mode for the first time a week ago?

    - by Acid2
    I would usually have my pc on all day and fully shut it down at night time before I went to bed. I decided to put it into sleep mode instead the other day and everything was fine but when I woke it from sleep, I was presented with the blue screen of death and it started with some weird noise that sounded like some spinning part was off balance or possibly hitting something periodically. Sounds like it could be a fan or maybe the HDD. I'm not sure why sleep mode would mess up the hardware. Anyway, now sometimes, randomly, when I turn my computer on from a previous shut down, I still get to hear the noise but the start-up is normal. Sometimes I don't hear anything for the entire duration while I have it on and sometimes it goes away after a few minutes and sometimes it doesn't and I have to restart, like it isn't going away right now. I can hear the noise as I type this. Anyone got possible solutions? I don't want to open the system and mess up other stuff. I'm also not sure if I should take it somewhere to have it fixed - it might not make the noise then and work like normal and nothing would seem like needing to be fixed. Add: I'm running Windows 7, if that's of any relevance.

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  • ownership of hard drive recoveery of files Windows 7

    - by Jeff
    Here is the issue. I have an old laptop that died that was running xp. I now have a win 7 laptop. I need to get the files off the old drive. Win 7 will not let me take ownership of the drive. I can runn the comand prompt in regular mode and do a dir on the drive that shows up as Q: drive in regular mode. I gives me the volume as c and the serial number. I can not take ownership in regular mode with the comand prompt or other means. Microsoft site says use safe mode with networking. So I go to safe mode the drive shows up as G: in safe mode. I use the comand prompt Takeown /f G: and get the device is not ready error. I am at a loss. All I want is to retrieve my files from this drive. Any ideas or sugestions. I don't see how you can dir and get some info in one mode and not acces it in another. I have to get ownership and permissions fixed to get in the drive to get my files. Thanks in advance. I might add that I am using a usb3.0 to ide/sata cable adapter. Software came with the device but I can't make heads or tails out of the manual to know if any of the software can help me. The soft ware is PCClone Ex lite, and Clone Drive Soft ware

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  • diffie-hellman ssh keyxchange

    - by Chuck
    Hi, I've set out to make a primitive SSH client in C#; you might remember me from posts such as http://stackoverflow.com/questions/2872279/c-primitive-ssh-connection-lowlevel hehe. Anyway, things are great up until the time when I initiate a DH key exchange. I've compared the traffic when I establish a ssh connection (from openssh client to openssh server), to the traffic when my client connects to the same openssh server. OpenSSH client - OpenSSH server (S for server, C for client): S: SSH-2.0-OpenSSH_5.1p1 Debian-6ubuntu2\r (saying hello) C: SSH-2.0-OpenSSH_5.2\r (introducing myself) C: Key Exchange Init (0x14 = 20) S: Key Exchange Init C: Diffie-Hellman GEX Request (0x22 = 34) (with DH GEX min, number of bits and max) S: Diffie-Hellman Key Exchange Reply (with P, G, etc.) C: Diffie-Hellman GEX Init S: Diffie-Hellman GEX Reply My client - OpenSSH server: S: SSH-2.0-OpenSSH_5.1p1 Debian-6ubuntu2\r (saying hello) C: SSH-2.0-Some_Name\r (introducing myself) C: Key Exchange Init (0x14 = 20) S: Key Exchange Init C: Diffie-Hellman GEX Request (0x22 = 34) (with DH GEX min, number of bits and max) and then a bogus TCP packet as reply (probably the server connection has been terminated after/upon GEX Request. I have yet to use AES128 (which I think is the encryption chosen, but I'm not sure how to verify this...), and I'm still sending in a non-compressed format, looking to get the P, G etc. values to make the DH calculations. So where I'm stranded is: RFC 4419 page 3 http://www.ietf.org/rfc/rfc4419.txt I've send SSH_MSG_KEY_DH_GEX_REQUEST, but the server does not respond SSH_MSG_KEX_DH_GEX_GROUP. Can anyone give me a little advice on what I'm not understanding here? Does the server not understand my GEX request (due to it expecting encryption, or?)? Any help is very much appreciated, thanks :)

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  • convert xml document to comma delimited (CSV) file using xslt stylesheet.

    - by Brad H
    I need some assistance converting an xml document to a CSV file using an xslt stylesheet. I am trying to use the following xsl and I can't seem to get it right. I want my comma delimited file to include column headings, followed by the data. My biggest issues are removing the final comma after the last item and inserting a carriage return so each group of data appears on a separate line. I have been using XML Notepad. <xsl:template match="/"> <xsl:element name="table"> <xsl:apply-templates select="/*/*[1]" mode="header" /> <xsl:apply-templates select="/*/*" mode="row" /> </xsl:element> </xsl:template> <xsl:template match="*" mode="header"> <xsl:element name="tr"> <xsl:apply-templates select="./*" mode="column" /> </xsl:element> </xsl:template> <xsl:template match="*" mode="row"> <xsl:element name="tr"> <xsl:apply-templates select="./*" mode="node" /> </xsl:element> </xsl:template> <xsl:template match="*" mode="column"> <xsl:element name="th"> <xsl:value-of select="translate(name(.),'qwertyuiopasdfghjklzxcvbnm_','QWERTYUIOPASDFGHJKLZXCVBNM ')" /> </xsl:element>, </xsl:template> <xsl:template match="*" mode="node"> <xsl:element name="td"> <xsl:value-of select="." /> </xsl:element>, </xsl:template>

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  • Is there a way to deserialize an object into "$this"?

    - by Andreas Bonini
    I'm writing a class to handle a memcached object. The idea was to create abstract class Cachable and all the cachable objects (such as User, Post, etc) would be subclasses of said class. The class offers some method such as Load() which calls the abstract function LoadFromDB() if the object is not cached, functions to refresh/invalidate the cache, etc. The main problem is in Load(); I wanted to do something similar: protected function Load($id) { $this->memcacheId = $id; $this->Connect(); $cached = $this->memcache->get(get_class($this) . ':' . $id); if($cached === false) { $this->SetLoaded(LoadFromDB($id)); UpdateCache(); } else { $this = $cached; $this->SetLoaded(true); } } Unfortunately I need $this to become $cached (the cached object); is there any way to do that? Was the "every cachable object derives from the cachable class" a bad design idea?

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  • Elegent methods for caching search results from RESTful service?

    - by Paul
    I have a RESTful web service which I access from the browser using JavaScript. As an example, say that this web service returns a list of all the Message resources assigned to me when I send a GET request to /messages/me. For performance reasons, I'd like to cache this response so that I don't have to re-fetch it every time I visit my Manage Messages web page. The cached response would expire after 5 minutes. If a Message resource is created "behind my back", say by the system admin, it's possible that I won't know about it for up to 5 minutes, until the cached search response expires and is re-fetched. This is acceptable, because it creates no confusion for me. However if I create a new Message resource which I know should be part of the search response, it becomes confusing when it doesn't appear on my Manage Messages page immediately. In general, when I knowingly create/delete/update a resource that invalidates a cached search response, I need that cached response to be expired/flushed immediately. The core problem which I can't figure out: I see no simple way of connecting the task of creating/deleting/updating a resource with the task of expiring the appropriate cached responses. In this example it seems simple, I could manually expire the cached search response whenever I create/delete/update a(ny) Message resource. But in a more complex system, keeping track of which search responses to expire under what circumstances will get clumsy quickly. If someone could suggest a simple solution or some clarifying thoughts, I'd appreciate it.

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  • Networking in VirtualBox

    - by Fat Bloke
    Networking in VirtualBox is extremely powerful, but can also be a bit daunting, so here's a quick overview of the different ways you can setup networking in VirtualBox, with a few pointers as to which configurations should be used and when. VirtualBox allows you to configure up to 8 virtual NICs (Network Interface Controllers) for each guest vm (although only 4 are exposed in the GUI) and for each of these NICs you can configure: Which virtualized NIC-type is exposed to the Guest. Examples include: Intel PRO/1000 MT Server (82545EM),  AMD PCNet FAST III (Am79C973, the default) or  a Paravirtualized network adapter (virtio-net). How the NIC operates with respect to your Host's physical networking. The main modes are: Network Address Translation (NAT) Bridged networking Internal networking Host-only networking NAT with Port-forwarding The choice of NIC-type comes down to whether the guest has drivers for that NIC.  VirtualBox, suggests a NIC based on the guest OS-type that you specify during creation of the vm, and you rarely need to modify this. But the choice of networking mode depends on how you want to use your vm (client or server) and whether you want other machines on your network to see it. So let's look at each mode in a bit more detail... Network Address Translation (NAT) This is the default mode for new vm's and works great in most situations when the Guest is a "client" type of vm. (i.e. most network connections are outbound). Here's how it works: When the guest OS boots,  it typically uses DHCP to get an IP address. VirtualBox will field this DHCP request and tell the guest OS its assigned IP address and the gateway address for routing outbound connections. In this mode, every vm is assigned the same IP address (10.0.2.15) because each vm thinks they are on their own isolated network. And when they send their traffic via the gateway (10.0.2.2) VirtualBox rewrites the packets to make them appear as though they originated from the Host, rather than the Guest (running inside the Host). This means that the Guest will work even as the Host moves from network to network (e.g. laptop moving between locations), and from wireless to wired connections too. However, how does another computer initiate a connection into a Guest?  e.g. connecting to a web server running in the Guest. This is not (normally) possible using NAT mode as there is no route into the Guest OS. So for vm's running servers we need a different networking mode.... Bridged Networking Bridged Networking is used when you want your vm to be a full network citizen, i.e. to be an equal to your host machine on the network. In this mode, a virtual NIC is "bridged" to a physical NIC on your host, like this: The effect of this is that each VM has access to the physical network in the same way as your host. It can access any service on the network such as external DHCP services, name lookup services, and routing information just as the host does. Logically, the network looks like this: The downside of this mode is that if you run many vm's you can quickly run out of IP addresses or your network administrator gets fed up with you asking for statically assigned IP addresses. Secondly, if your host has multiple physical NICs (e.g. Wireless and Wired) you must reconfigure the bridge when your host jumps networks.  Hmm, so what if you want to run servers in vm's but don't want to involve your network administrator? Maybe one of the next 2 modes is for you... Internal Networking When you configure one or more vm's to sit on an Internal network, VirtualBox ensures that all traffic on that network stays within the host and is only visible to vm's on that virtual network. Configuration looks like this: The internal network ( in this example "intnet" ) is a totally isolated network and so is very "quiet". This is good for testing when you need a separate, clean network, and you can create sophisticated internal networks with vm's that provide their own services to the internal network. (e.g. Active Directory, DHCP, etc). Note that not even the Host is a member of the internal network, but this mode allows vm's to function even when the Host is not connected to a network (e.g. on a plane). Note that in this mode, VirtualBox provides no "convenience" services such as DHCP, so your machines must be statically configured or one of the vm's needs to provide a DHCP/Name service. Multiple internal networks are possible and you can configure vm's to have multiple NICs to sit across internal and other network modes and thereby provide routes if needed. But all this sounds tricky. What if you want an Internal Network that the host participates on with VirtualBox providing IP addresses to the Guests? Ah, then for this, you might want to consider Host-only Networking... Host-only Networking Host-only Networking is like Internal Networking in that you indicate which network the Guest sits on, in this case, "vboxnet0": All vm's sitting on this "vboxnet0" network will see each other, and additionally, the host can see these vm's too. However, other external machines cannot see Guests on this network, hence the name "Host-only". Logically, the network looks like this: This looks very similar to Internal Networking but the host is now on "vboxnet0" and can provide DHCP services. To configure how a Host-only network behaves, look in the VirtualBox Manager...Preferences...Network dialog: Port-Forwarding with NAT Networking Now you may think that we've provided enough modes here to handle every eventuality but here's just one more... What if you cart around a mobile-demo or dev environment on, say, a laptop and you have one or more vm's that you need other machines to connect into? And you are continually hopping onto different (customer?) networks. In this scenario: NAT - won't work because external machines need to connect in. Bridged - possibly an option, but does your customer want you eating IP addresses and can your software cope with changing networks? Internal - we need the vm(s) to be visible on the network, so this is no good. Host-only - same problem as above, we want external machines to connect in to the vm's. Enter Port-forwarding to save the day! Configure your vm's to use NAT networking; Add Port Forwarding rules; External machines connect to "host":"port number" and connections are forwarded by VirtualBox to the guest:port number specified. For example, if your vm runs a web server on port 80, you could set up rules like this:  ...which reads: "any connections on port 8080 on the Host will be forwarded onto this vm's port 80".  This provides a mobile demo system which won't need re-configuring every time you open your laptop lid. Summary VirtualBox has a very powerful set of options allowing you to set up almost any configuration your heart desires. For more information, check out the VirtualBox User Manual on Virtual Networking. -FB 

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  • Characteristics of a Web service that promote reusability and change

    Characteristics of a Web service that promote reusability and change:  Standardized Data Exchange Formats (XML, JSON) Standardized communication protocols (Soap, Rest) Promotes Loosely Coupled Systems  Standardized Data Exchange Formats (XML, JSON) XML W3.org defines Extensible Markup Language (XML) as a simplistic text format derived from SGML. XML was designed to solve challenges found in large-scale electronic publishing. In addition,  XML is playing an important role in the exchange of data primarily focusing on data exchange on the web. JSON JavaScript Object Notation (JSON) is a human-readable text-based standard designed for data interchange. This format is used for serializing and transmitting data over a network connection in a structured format. The primary use of JSON is to transmit data between a server and web application. JSON is an alternative to XML. Standardized communication protocols (Soap, Rest) Soap W3Scools.com defines SOAP as a simple XML-based protocol. This protocol lets applications exchange data over HTTP.  SOAP provides a way to communicate between applications running on different operating systems, with different technologies and programming languages. Rest In 2007, Stefan Tilkov defines Representational State Transfer (REST) as a set of principles that outlines how Web standards are supposed to be used.  Using REST in an application will ensure that it exploits the Web’s architecture to its benefit. Promotes Loosely Coupled Systems “Loose coupling as an approach to interconnecting the components in a system or network so that those components, also called elements, depend on each other to the least extent practicable. Coupling refers to the degree of direct knowledge that one element has of another.” (TechTarget.com, 2007) “Loosely coupled system can be easily broken down into definable elements. The extent of coupling in a system can be measured by mapping the maximum number of element changes that can occur without adverse effects. Examples of such changes include adding elements, removing elements, renaming elements, reconfiguring elements, modifying internal element characteristics and rearranging the way in which elements are interconnected.” (TechTarget.com, 2007) References: W3C. (2011). Extensible Markup Language (XML). Retrieved from W3.org: http://www.w3.org/XML/ W3Scools.com. (2011). SOAP Introduction. Retrieved from W3Scools.com: http://www.w3schools.com/soap/soap_intro.asp Tilkov, Stefan. (2007). A Brief Introduction to REST. Retrieved from Infoq.com: http://www.infoq.com/articles/rest-introduction TechTarget.com. (2011). loose coupling. Retrieved from TechTarget.com: http://searchnetworking.techtarget.com/definition/loose-coupling

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  • External HDD USB 3.0 failure

    - by Philip
    [ 2560.376113] usb 9-1: new high-speed USB device number 2 using xhci_hcd [ 2560.376186] usb 9-1: Device not responding to set address. [ 2560.580136] usb 9-1: Device not responding to set address. [ 2560.784104] usb 9-1: device not accepting address 2, error -71 [ 2560.840127] hub 9-0:1.0: unable to enumerate USB device on port 1 [ 2561.080182] usb 10-1: new SuperSpeed USB device number 5 using xhci_hcd [ 2566.096163] usb 10-1: device descriptor read/8, error -110 [ 2566.200096] usb 10-1: new SuperSpeed USB device number 5 using xhci_hcd [ 2571.216175] usb 10-1: device descriptor read/8, error -110 [ 2571.376138] hub 10-0:1.0: unable to enumerate USB device on port 1 [ 2571.744174] usb 10-1: new SuperSpeed USB device number 7 using xhci_hcd [ 2576.760116] usb 10-1: device descriptor read/8, error -110 [ 2576.864074] usb 10-1: new SuperSpeed USB device number 7 using xhci_hcd [ 2581.880153] usb 10-1: device descriptor read/8, error -110 [ 2582.040123] hub 10-0:1.0: unable to enumerate USB device on port 1 [ 2582.224139] hub 9-0:1.0: unable to enumerate USB device on port 1 [ 2582.464177] usb 10-1: new SuperSpeed USB device number 9 using xhci_hcd [ 2587.480122] usb 10-1: device descriptor read/8, error -110 [ 2587.584079] usb 10-1: new SuperSpeed USB device number 9 using xhci_hcd [ 2592.600150] usb 10-1: device descriptor read/8, error -110 [ 2592.760134] hub 10-0:1.0: unable to enumerate USB device on port 1 [ 2593.128175] usb 10-1: new SuperSpeed USB device number 11 using xhci_hcd [ 2598.144183] usb 10-1: device descriptor read/8, error -110 [ 2598.248109] usb 10-1: new SuperSpeed USB device number 11 using xhci_hcd [ 2603.264171] usb 10-1: device descriptor read/8, error -110 [ 2603.480157] usb 10-1: new SuperSpeed USB device number 12 using xhci_hcd [ 2608.496162] usb 10-1: device descriptor read/8, error -110 [ 2608.600091] usb 10-1: new SuperSpeed USB device number 12 using xhci_hcd [ 2613.616166] usb 10-1: device descriptor read/8, error -110 [ 2613.832170] usb 10-1: new SuperSpeed USB device number 13 using xhci_hcd [ 2618.848135] usb 10-1: device descriptor read/8, error -110 [ 2618.952079] usb 10-1: new SuperSpeed USB device number 13 using xhci_hcd [ 2623.968155] usb 10-1: device descriptor read/8, error -110 [ 2624.184176] usb 10-1: new SuperSpeed USB device number 14 using xhci_hcd [ 2629.200124] usb 10-1: device descriptor read/8, error -110 [ 2629.304075] usb 10-1: new SuperSpeed USB device number 14 using xhci_hcd [ 2634.320172] usb 10-1: device descriptor read/8, error -110 [ 2634.424135] hub 10-0:1.0: unable to enumerate USB device on port 1 [ 2634.776186] usb 10-1: new SuperSpeed USB device number 15 using xhci_hcd [ 2639.792105] usb 10-1: device descriptor read/8, error -110 [ 2639.896090] usb 10-1: new SuperSpeed USB device number 15 using xhci_hcd [ 2644.912172] usb 10-1: device descriptor read/8, error -110 [ 2645.128174] usb 10-1: new SuperSpeed USB device number 16 using xhci_hcd [ 2650.144160] usb 10-1: device descriptor read/8, error -110 [ 2650.248062] usb 10-1: new SuperSpeed USB device number 16 using xhci_hcd [ 2655.264120] usb 10-1: device descriptor read/8, error -110 [ 2655.480182] usb 10-1: new SuperSpeed USB device number 17 using xhci_hcd [ 2660.496121] usb 10-1: device descriptor read/8, error -110 [ 2660.600086] usb 10-1: new SuperSpeed USB device number 17 using xhci_hcd [ 2665.616167] usb 10-1: device descriptor read/8, error -110 [ 2665.832177] usb 10-1: new SuperSpeed USB device number 18 using xhci_hcd [ 2670.848110] usb 10-1: device descriptor read/8, error -110 [ 2670.952066] usb 10-1: new SuperSpeed USB device number 18 using xhci_hcd [ 2675.968081] usb 10-1: device descriptor read/8, error -110 [ 2676.072124] hub 10-0:1.0: unable to enumerate USB device on port 1 [ 2786.104531] xhci_hcd 0000:02:00.0: remove, state 4 [ 2786.104546] usb usb10: USB disconnect, device number 1 [ 2786.104686] xHCI xhci_drop_endpoint called for root hub [ 2786.104692] xHCI xhci_check_bandwidth called for root hub [ 2786.104942] xhci_hcd 0000:02:00.0: USB bus 10 deregistered [ 2786.105054] xhci_hcd 0000:02:00.0: remove, state 4 [ 2786.105065] usb usb9: USB disconnect, device number 1 [ 2786.105176] xHCI xhci_drop_endpoint called for root hub [ 2786.105181] xHCI xhci_check_bandwidth called for root hub [ 2786.109787] xhci_hcd 0000:02:00.0: USB bus 9 deregistered [ 2786.110134] xhci_hcd 0000:02:00.0: PCI INT A disabled [ 2794.268445] pci 0000:02:00.0: [1b73:1000] type 0 class 0x000c03 [ 2794.268483] pci 0000:02:00.0: reg 10: [mem 0x00000000-0x0000ffff] [ 2794.268689] pci 0000:02:00.0: PME# supported from D0 D3hot [ 2794.268700] pci 0000:02:00.0: PME# disabled [ 2794.276383] pci 0000:02:00.0: BAR 0: assigned [mem 0xd7800000-0xd780ffff] [ 2794.276398] pci 0000:02:00.0: BAR 0: set to [mem 0xd7800000-0xd780ffff] (PCI address [0xd7800000-0xd780ffff]) [ 2794.276419] pci 0000:02:00.0: no hotplug settings from platform [ 2794.276658] xhci_hcd 0000:02:00.0: enabling device (0000 -> 0002) [ 2794.276675] xhci_hcd 0000:02:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16 [ 2794.276762] xhci_hcd 0000:02:00.0: setting latency timer to 64 [ 2794.276771] xhci_hcd 0000:02:00.0: xHCI Host Controller [ 2794.276913] xhci_hcd 0000:02:00.0: new USB bus registered, assigned bus number 9 [ 2794.395760] xhci_hcd 0000:02:00.0: irq 16, io mem 0xd7800000 [ 2794.396141] xHCI xhci_add_endpoint called for root hub [ 2794.396144] xHCI xhci_check_bandwidth called for root hub [ 2794.396195] hub 9-0:1.0: USB hub found [ 2794.396203] hub 9-0:1.0: 1 port detected [ 2794.396305] xhci_hcd 0000:02:00.0: xHCI Host Controller [ 2794.396371] xhci_hcd 0000:02:00.0: new USB bus registered, assigned bus number 10 [ 2794.396496] xHCI xhci_add_endpoint called for root hub [ 2794.396499] xHCI xhci_check_bandwidth called for root hub [ 2794.396547] hub 10-0:1.0: USB hub found [ 2794.396553] hub 10-0:1.0: 1 port detected [ 2798.004084] usb 1-3: new high-speed USB device number 8 using ehci_hcd [ 2798.140824] scsi21 : usb-storage 1-3:1.0 [ 2820.176116] usb 1-3: reset high-speed USB device number 8 using ehci_hcd [ 2824.000526] scsi 21:0:0:0: Direct-Access BUFFALO HD-PZU3 0001 PQ: 0 ANSI: 6 [ 2824.002263] sd 21:0:0:0: Attached scsi generic sg2 type 0 [ 2824.003617] sd 21:0:0:0: [sdb] 1953463728 512-byte logical blocks: (1.00 TB/931 GiB) [ 2824.005139] sd 21:0:0:0: [sdb] Write Protect is off [ 2824.005149] sd 21:0:0:0: [sdb] Mode Sense: 1f 00 00 08 [ 2824.009084] sd 21:0:0:0: [sdb] No Caching mode page present [ 2824.009094] sd 21:0:0:0: [sdb] Assuming drive cache: write through [ 2824.011944] sd 21:0:0:0: [sdb] No Caching mode page present [ 2824.011952] sd 21:0:0:0: [sdb] Assuming drive cache: write through [ 2824.049153] sdb: sdb1 [ 2824.051814] sd 21:0:0:0: [sdb] No Caching mode page present [ 2824.051821] sd 21:0:0:0: [sdb] Assuming drive cache: write through [ 2824.051825] sd 21:0:0:0: [sdb] Attached SCSI disk [ 2839.536624] usb 1-3: USB disconnect, device number 8 [ 2844.620178] usb 10-1: new SuperSpeed USB device number 2 using xhci_hcd [ 2844.640281] scsi22 : usb-storage 10-1:1.0 [ 2850.326545] scsi 22:0:0:0: Direct-Access BUFFALO HD-PZU3 0001 PQ: 0 ANSI: 6 [ 2850.327560] sd 22:0:0:0: Attached scsi generic sg2 type 0 [ 2850.329561] sd 22:0:0:0: [sdb] 1953463728 512-byte logical blocks: (1.00 TB/931 GiB) [ 2850.329889] sd 22:0:0:0: [sdb] Write Protect is off [ 2850.329897] sd 22:0:0:0: [sdb] Mode Sense: 1f 00 00 08 [ 2850.330223] sd 22:0:0:0: [sdb] No Caching mode page present [ 2850.330231] sd 22:0:0:0: [sdb] Assuming drive cache: write through [ 2850.331414] sd 22:0:0:0: [sdb] No Caching mode page present [ 2850.331423] sd 22:0:0:0: [sdb] Assuming drive cache: write through [ 2850.384116] usb 10-1: USB disconnect, device number 2 [ 2850.392050] sd 22:0:0:0: [sdb] Unhandled error code [ 2850.392056] sd 22:0:0:0: [sdb] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [ 2850.392061] sd 22:0:0:0: [sdb] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00 [ 2850.392074] end_request: I/O error, dev sdb, sector 0 [ 2850.392079] quiet_error: 70 callbacks suppressed [ 2850.392082] Buffer I/O error on device sdb, logical block 0 [ 2850.392194] ldm_validate_partition_table(): Disk read failed. [ 2850.392271] Dev sdb: unable to read RDB block 0 [ 2850.392377] sdb: unable to read partition table [ 2850.392581] sd 22:0:0:0: [sdb] READ CAPACITY failed [ 2850.392584] sd 22:0:0:0: [sdb] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [ 2850.392588] sd 22:0:0:0: [sdb] Sense not available. [ 2850.392613] sd 22:0:0:0: [sdb] Asking for cache data failed [ 2850.392617] sd 22:0:0:0: [sdb] Assuming drive cache: write through [ 2850.392621] sd 22:0:0:0: [sdb] Attached SCSI disk [ 2850.732182] usb 10-1: new SuperSpeed USB device number 3 using xhci_hcd [ 2850.752228] scsi23 : usb-storage 10-1:1.0 [ 2851.752709] scsi 23:0:0:0: Direct-Access BUFFALO HD-PZU3 0001 PQ: 0 ANSI: 6 [ 2851.754481] sd 23:0:0:0: Attached scsi generic sg2 type 0 [ 2851.756576] sd 23:0:0:0: [sdb] 1953463728 512-byte logical blocks: (1.00 TB/931 GiB) [ 2851.758426] sd 23:0:0:0: [sdb] Write Protect is off [ 2851.758436] sd 23:0:0:0: [sdb] Mode Sense: 1f 00 00 08 [ 2851.758779] sd 23:0:0:0: [sdb] No Caching mode page present [ 2851.758787] sd 23:0:0:0: [sdb] Assuming drive cache: write through [ 2851.759968] sd 23:0:0:0: [sdb] No Caching mode page present [ 2851.759977] sd 23:0:0:0: [sdb] Assuming drive cache: write through [ 2851.817710] sdb: sdb1 [ 2851.820562] sd 23:0:0:0: [sdb] No Caching mode page present [ 2851.820568] sd 23:0:0:0: [sdb] Assuming drive cache: write through [ 2851.820572] sd 23:0:0:0: [sdb] Attached SCSI disk [ 2852.060352] usb 10-1: reset SuperSpeed USB device number 3 using xhci_hcd [ 2852.076533] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b19060 [ 2852.076538] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b1908c [ 2852.196329] usb 10-1: reset SuperSpeed USB device number 3 using xhci_hcd [ 2852.212593] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b19060 [ 2852.212599] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b1908c [ 2852.456290] usb 10-1: reset SuperSpeed USB device number 3 using xhci_hcd [ 2852.472402] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b19060 [ 2852.472408] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b1908c [ 2852.624304] usb 10-1: reset SuperSpeed USB device number 3 using xhci_hcd [ 2852.640531] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b19060 [ 2852.640536] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b1908c [ 2852.772296] usb 10-1: reset SuperSpeed USB device number 3 using xhci_hcd [ 2852.788536] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b19060 [ 2852.788541] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b1908c [ 2852.920349] usb 10-1: reset SuperSpeed USB device number 3 using xhci_hcd [ 2852.936536] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b19060 [ 2852.936540] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b1908c [ 2853.072287] usb 10-1: reset SuperSpeed USB device number 3 using xhci_hcd [ 2853.088565] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b19060 [ 2853.088570] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b1908c [ 2884.176339] usb 10-1: reset SuperSpeed USB device number 3 using xhci_hcd [ 2884.192561] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b19060 [ 2884.192567] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b1908c [ 2884.320349] usb 10-1: reset SuperSpeed USB device number 3 using xhci_hcd [ 2884.336526] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b19060 [ 2884.336531] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b1908c [ 2884.468344] usb 10-1: reset SuperSpeed USB device number 3 using xhci_hcd [ 2884.484551] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b19060 [ 2884.484556] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b1908c [ 2884.612349] usb 10-1: reset SuperSpeed USB device number 3 using xhci_hcd [ 2884.628540] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b19060 [ 2884.628545] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b1908c [ 2884.756350] usb 10-1: reset SuperSpeed USB device number 3 using xhci_hcd [ 2884.772528] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b19060 [ 2884.772533] xhci_hcd 0000:02:00.0: xHCI xhci_drop_endpoint called with disabled ep f6b1908c [ 2884.848116] usb 10-1: USB disconnect, device number 3 [ 2884.851493] scsi 23:0:0:0: [sdb] killing request [ 2884.851501] scsi 23:0:0:0: [sdb] killing request [ 2884.851699] scsi 23:0:0:0: [sdb] Unhandled error code [ 2884.851702] scsi 23:0:0:0: [sdb] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [ 2884.851708] scsi 23:0:0:0: [sdb] CDB: Read(10): 28 00 00 5f 2b ee 00 00 3e 00 [ 2884.851721] end_request: I/O error, dev sdb, sector 6237166 [ 2884.851726] Buffer I/O error on device sdb1, logical block 6237102 [ 2884.851730] Buffer I/O error on device sdb1, logical block 6237103 [ 2884.851738] Buffer I/O error on device sdb1, logical block 6237104 [ 2884.851741] Buffer I/O error on device sdb1, logical block 6237105 [ 2884.851744] Buffer I/O error on device sdb1, logical block 6237106 [ 2884.851747] Buffer I/O error on device sdb1, logical block 6237107 [ 2884.851750] Buffer I/O error on device sdb1, logical block 6237108 [ 2884.851753] Buffer I/O error on device sdb1, logical block 6237109 [ 2884.851757] Buffer I/O error on device sdb1, logical block 6237110 [ 2884.851807] scsi 23:0:0:0: [sdb] Unhandled error code [ 2884.851810] scsi 23:0:0:0: [sdb] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [ 2884.851813] scsi 23:0:0:0: [sdb] CDB: Read(10): 28 00 00 5f 2c 2c 00 00 3e 00 [ 2884.851824] end_request: I/O error, dev sdb, sector 6237228 [ 2885.168190] usb 10-1: new SuperSpeed USB device number 4 using xhci_hcd [ 2885.188268] scsi24 : usb-storage 10-1:1.0 Please help me with my problem. I got this after running dmesg.

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  • Know More About Oracle Row Lock

    - by Liu Maclean(???)
    ??????Oracle??????????row lock,??ORACLE????????????????????,row lock???????????????????????????????,??Server Process?pin????block buffer????????? ????????,?process A ??update???????? Z?????????, ???????rollback???commit;??Process B??????DML??, ???????rowid???? Z???, ???????????process A????????ITL???,????????cleanout??,????????row???????????commit, ???????Process B????”enq: TX – row lock contention”??????? ????Process B????????????? ?????????Process A???????row,??Process B???????”enq: TX – row lock contention”???? ????????  ????????: SESSION A: SQL> select * from v$version; BANNER ---------------------------------------------------------------- Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bi PL/SQL Release 10.2.0.5.0 - Production CORE    10.2.0.5.0      Production TNS for Linux: Version 10.2.0.5.0 - Production NLSRTL Version 10.2.0.5.0 - Production SQL> select * from global_name; GLOBAL_NAME -------------------------------------------------------------------------------- www.oracledatabase12g.com SQL> create table maclean_lock(t1 int); Table created. SQL> insert into maclean_lock values (1); 1 row created. SQL> commit; Commit complete. SQL> select dbms_rowid.rowid_block_number(rowid),dbms_rowid.rowid_relative_fno(rowid) from maclean_lock; DBMS_ROWID.ROWID_BLOCK_NUMBER(ROWID) DBMS_ROWID.ROWID_RELATIVE_FNO(ROWID) ------------------------------------ ------------------------------------                                67642                                    1 SQL>  select distinct sid from v$mystat;        SID ----------        142 SQL> select pid,spid from v$process where addr = ( select paddr from v$session where sid=(select distinct sid from v$mystat));        PID SPID ---------- ------------         17 15636 ??SESSION A ????savepoint ,?update ?????????         SQL>  savepoint NONLOCK; Savepoint created. SQL> select * From v$Lock where sid=142; no rows selected SQL> set linesize 140 pagesize 1400 SQL>  update maclean_lock set t1=t1+2; 1 row updated. SQL> select * From v$Lock where sid=142; ADDR             KADDR                   SID TY        ID1        ID2      LMODE    REQUEST      CTIME      BLOCK ---------------- ---------------- ---------- -- ---------- ---------- ---------- ---------- ---------- ---------- 0000000091FC69F0 0000000091FC6A18        142 TM      55829          0          3          0          6          0 00000000914B4008 00000000914B4040        142 TX     393232        609          6          0          6          0         SQL> select dump(3,16) from dual; DUMP(3,16) -------------------------------------------------------------------------------- Typ=2 Len=2: c1,4 ALTER SYSTEM DUMP DATAFILE 1 BLOCK 67642;  Object id on Block? Y  seg/obj: 0xda16  csc: 0x00.234718  itc: 2  flg: O  typ: 1 - DATA      fsl: 0  fnx: 0x0 ver: 0x01  Itl           Xid                  Uba         Flag  Lck        Scn/Fsc 0x01   0x000a.00f.000001e0  0x00800075.02a6.29  C---    0  scn 0x0000.00234711 0x02   0x0007.018.000001fe  0x0080065c.017a.02  ----    1  fsc 0x0000.00000000 data_block_dump,data header at 0x81d185c =============== tsiz: 0x1fa0 hsiz: 0x14 pbl: 0x081d185c bdba: 0x0041083a      76543210 flag=-------- ntab=1 nrow=1 frre=-1 fsbo=0x14 fseo=0x1f9a avsp=0x1f83 tosp=0x1f83 0xe:pti[0]      nrow=1  offs=0 0x12:pri[0]     offs=0x1f9a block_row_dump: tab 0, row 0, @0x1f9a tl: 6 fb: --H-FL-- lb: 0x2  cc: 1 col  0: [ 2]  c1 04 end_of_block_dump ?? BLOCK DUMP ???? ??????XID=0x0007.018.000001fe ?transaction?? lb:0x1 ??SESSION B ,?????UPDATE?? ???enq: TX - row lock contention ?? SQL> select distinct sid from v$mystat;        SID ----------        140 SQL> select pid,spid from v$process where addr = ( select paddr from v$session where sid=(select distinct sid from v$mystat));        PID SPID ---------- ------------         24 15652 SQL> alter system set "_trace_events"='10000-10999:255:24'; System altered.         SQL> update maclean_lock set t1=t1+2; select * From v$Lock where sid=142 or sid=140 order by sid; SESSION C: SQL> select * From v$Lock where sid=142 or sid=140 order by sid; ADDR             KADDR                   SID TY        ID1        ID2      LMODE    REQUEST      CTIME      BLOCK ---------------- ---------------- ---------- -- ---------- ---------- ---------- ---------- ---------- ---------- 0000000091FC6B10 0000000091FC6B38        140 TM      55829          0          3          0         84          0 00000000924F4A58 00000000924F4A78        140 TX     458776        510          0          6         84          0 00000000914B51E8 00000000914B5220        142 TX     458776        510          6          0        312          1 0000000091FC69F0 0000000091FC6A18        142 TM      55829          0          3          0        312          0 ???? SESSION B SID=140 ?SESSION A ?TX ENQUEUE ?X mode?REQUEST SQL> oradebug dump systemstate 266; Statement processed. SESSION B waiter's enqueue lock       SO: 0x924f4a58, type: 5, owner: 0x92bb8dc8, flag: INIT/-/-/0x00       (enqueue) TX-00070018-000001FE    DID: 0001-0018-00000022       lv: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  res_flag: 0x6       req: X, lock_flag: 0x0, lock: 0x924f4a78, res: 0x925617c0       own: 0x92b76be0, sess: 0x92b76be0, proc: 0x92a737a0, prv: 0x925617e0 TX-00070018-000001FE=> TX 458776 510 SESSION A owner's enqueue lock       SO: 0x914b51e8, type: 40, owner: 0x92b796d0, flag: INIT/-/-/0x00       (trans) flg = 0x1e03, flg2 = 0xc0000, prx = 0x0, ros = 2147483647 bsn = 0xed5 bndsn = 0xee7 spn = 0xef7       efd = 3       file:xct.c lineno:1179       DID: 0001-0011-000000C2       parent xid: 0x0000.000.00000000       env: (scn: 0x0000.00234718  xid: 0x0007.018.000001fe  uba: 0x0080065c.017a.02  statement num=0  parent xid: xid: 0x0000.000.00000000  scn: 0x00 00.00234718 0sch: scn: 0x0000.00000000)       cev: (spc = 7818  arsp = 914e8310  ubk tsn: 1 rdba: 0x0080065c  useg tsn: 1 rdba: 0x00800069             hwm uba: 0x0080065c.017a.02  col uba: 0x00000000.0000.00             num bl: 1 bk list: 0x91435070)             cr opc: 0x0 spc: 7818 uba: 0x0080065c.017a.02       (enqueue) TX-00070018-000001FE    DID: 0001-0011-000000C2       lv: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  res_flag: 0x6       mode: X, lock_flag: 0x0, lock: 0x914b5220, res: 0x925617c0       own: 0x92b796d0, sess: 0x92b796d0, proc: 0x92a6ffd8, prv: 0x925617d0        xga: 0x8b7c6d40, heap: UGA       Trans IMU st: 2 Pool index 65535, Redo pool 0x914b58d0, Undo pool 0x914b59b8       Redo pool range [0x86de640 0x86de640 0x86e0e40]       Undo pool range [0x86dbe40 0x86dbe40 0x86de640]         ----------------------------------------         SO: 0x91435070, type: 39, owner: 0x914b51e8, flag: -/-/-/0x00         (List of Blocks) next index = 1         index   itli   buffer hint   rdba       savepoint         -----------------------------------------------------------             0      2   0x647f1fc8    0x41083a     0xee7 ?SESSION A? ROLLBACK ?savepoint: SQL> rollback to NONLOCK; Rollback complete. ????savepoint ??update??????? ??UPDATE???????? ROLLBACK: SQL> select * From v$Lock where sid=142 or sid=140; ADDR             KADDR                   SID TY        ID1        ID2      LMODE    REQUEST      CTIME      BLOCK ---------------- ---------------- ---------- -- ---------- ---------- ---------- ---------- ---------- ---------- 00000000924F4A58 00000000924F4A78        140 TX     458776        510          0          6        822          0 0000000091FC6B10 0000000091FC6B38        140 TM      55829          0          3          0        822          0 00000000914B51E8 00000000914B5220        142 TX     458776        510          6          0       1050          1 ???? SESSION A 142 ???SAVEPOINT ???????TM LOCK ????? ROLLBACK TO SAVEPOINT?????SESSION???TX LOCK!!!! ??????SESSION 142???TX ID1=458776 ID2=510, ????ROLLBACK TO SAVEPOINT?????????ABORT TRANSACTION ?? SESSION B  SID=140??  SESSION A ?? , ?????????SESSION B? update???HANG?? ?????????CACHE?????:  Object id on Block? Y  seg/obj: 0xda16  csc: 0x00.2347b7  itc: 2  flg: O  typ: 1 - DATA      fsl: 0  fnx: 0x0 ver: 0x01  Itl           Xid                  Uba         Flag  Lck        Scn/Fsc 0x01   0x000a.00f.000001e0  0x00800075.02a6.29  C---    0  scn 0x0000.00234711 0x02   0x0000.000.00000000  0x00000000.0000.00  ----    0  fsc 0x0000.00000000 data_block_dump,data header at 0x745d85c =============== tsiz: 0x1fa0 hsiz: 0x14 pbl: 0x0745d85c bdba: 0x0041083a      76543210 flag=-------- ntab=1 nrow=1 frre=-1 fsbo=0x14 fseo=0x1f9a avsp=0x1f83 tosp=0x1f83 0xe:pti[0]      nrow=1  offs=0 0x12:pri[0]     offs=0x1f9a block_row_dump: tab 0, row 0, @0x1f9a tl: 6 fb: --H-FL-- lb: 0x0  cc: 1 col  0: [ 2]  c1 02 end_of_block_dump ???? ITL=0x02? ?????????,col  0: [ 2]  c1 02 ????????? ?????????SESSION D ,??????row lock?? ?UPDATE???????? SESSION D: SQL> update maclean_lock set t1=t1+2; 1 row updated. SQL> rollback; Rollback complete. ??SESSION B ??????????? ?????ORACLE????????, ??????????? TX lock?? row lock , ????????2??? row lock?????????, ?TX lock????????ENQUEUE LOCK???? ?????????PROCESS K?DML???????????????????????,??????????TX LOCK, ????PROCESS Z?????????????????????????ROW LOCK????????, ???????OLTP?????????????????????? ??ROW LOCK?Release ??????TX?ENQUEUE LOCK,?????????Process J ????????????, Process K??????????? ,Process K?????????,???row piece?lb??0x0 ,?????ITL, Process Z???ITL???????Process J????XID,?????Process J?????TX lock, PROCESS K ???TX resource?Enqueue Waiter Linked List?????X mode(exclusive)?enqueue lock? ???Process J??TX lock?,Process J?????TX resource?Enqueue Waiter Linked List ???Process K??????,??POST?????Process K? TX lock??????, ???????row lock???????,????????? ?????????? ?????: SESSION A ???PID =17 ?????????????????? SESSION B ???PID =24 ??????? "_trace_events"='10000-10999:255:24';  KST trace ??????? Server Process??? SESSION A PID=17  ?? acqure?SX mode???TM Lock ,?? ????Transaction?????UNDO SEGMENT 7,???XID 7.24.510, ?acquire ?X mode? TX-00070018-000001fe ? ?????? 00070018-000001fe ???? 7- 24 - 510? XID ? 781F4B8A:007A569C    17   142 10704  83 ksqgtl: acquire TM-0000da15-00000000 mode=SX flags=GLOBAL|XACT why="contention" 781F4B92:007A569D    17   142 10704  19 ksqgtl: SUCCESS 781F4BB3:007A569E    17   142 10812   2 0x000000000041083A 0x0000000000000000 0x0000000000234717 781F4BBA:007A569F    17   142 10812   3 0x0000000000000000 0x0000000000000000 0x0000000000000000 781F4BC0:007A56A0    17   142 10812   4 0x0000000000000000 0x0000000000000000 0x0000000000000000 781F4BD3:007A56A1    17   142 10812   5 0x000000000041083A 0x0000000000000000 0x0000000000000000 781F4BFE:007A56A2    17   142 10811   1 0x000000000041083A 0x0000000000000000 0x0000000000234711 0x0000000000000002 781F4C06:007A56A3    17   142 10811   2 0x000000000041083A 0x0000000000000000 0x0000000000234718 0x00007FA074EDA560 781F4C26:007A56A4    17   142 10813   1 ktubnd: Bind usn 7 nax 1 nbx 0 lng 0 par 0 781F4C43:007A56A5    17   142 10813   2 ktubnd: Txn Bound xid: 7.24.510 781F4C4A:007A56A6    17   142 10704  83 ksqgtl: acquire TX-00070018-000001fe mode=X flags=GLOBAL|XACT why="contention" 781F4C51:007A56A7    17   142 10704  19 ksqgtl: SUCCESS ?????????? ???????? 781F4CBF:007A56A8    17   142 10005   1 KSL WAIT BEG [SQL*Net message to client] 1650815232/0x62657100 1/0x1 0/0x0 781F4CCC:007A56A9    17   142 10005   2 KSL WAIT END [SQL*Net message to client] 1650815232/0x62657100 1/0x1 0/0x0 time=13 781F4CDE:007A56AA    17   142 10005   1 KSL WAIT BEG [SQL*Net message from client] 1650815232/0x62657100 1/0x1 0/0x0 786BD85D:007A57E0    17   142 10005   2 KSL WAIT END [SQL*Net message from client] 1650815232/0x62657100 1/0x1 0/0x0 time=5016447 786BD966:007A57E1    17   142 10005   1 KSL WAIT BEG [SQL*Net message to client] 1650815232/0x62657100 1/0x1 0/0x0 786BD96E:007A57E2    17   142 10005   2 KSL WAIT END [SQL*Net message to client] 1650815232/0x62657100 1/0x1 0/0x0 time=8 SESSION B ???PID =24  ,??????? SX mode? TM lock,??row lock? acquire X mode?TX-00070018-000001fe ksqgtl: acquire TM-0000da15-00000000 mode=SX flags=GLOBAL|XACT why="contention" ksqgtl: SUCCESS 0x000000000041083A 0x0000000000000000 0x00000000002354F8 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x000000000041083A 0x0000000000000000 0x00000000002354F8 0x0000000000000001 0x000000000041083A 0x0000000000000000 0x00000000002354F8 0x0000000008A63780 0x0000000000000001 0x0000000000800861 0x0000000000000241 0x0000000000000001 0x000000000041083A 0x0000000000000001 0x0000000000000001 0x000000000041083A 0x0000000000000000 0x00000000002354F9 0x0000000000000002 ksqgtl: acquire TX-00070018-000001fe mode=X flags=GLOBAL|LONG why="row lock contention" C4048EBD:007F52B6    24   140 10005   2 KSL WAIT END [enq: TX - row lock contention] 1415053318/0x54580006 458776/0x70018 510/0x1fe time=2929879 C4048ED4:007F52B7    24   140 10005   1 KSL WAIT BEG [enq: TX - row lock contention] 1415053318/0x54580006 458776/0x70018 510/0x1fe C43146CA:007F535E    24   140 10005   2 KSL WAIT END [enq: TX - row lock contention] 1415053318/0x54580006 458776/0x70018 510/0x1fe time=2930676 ????????? ,PID=24 ??????ksqcmi???????? deadlock C43146D9:007F535F    24   140 10704 134 ksqcmi: performing local deadlock detection on TX-00070018-000001fe C43146F8:007F5360    24   140 10704 150 ksqcmi: deadlock not detected on TX-00070018-000001fe ?? ??? PID 17 ??ROLLBACK ???? ,????????: PID 17 ROLLBACK; D7A495BB:007F9D3E    17   142 10005   4 KSL POST SENT postee=24 loc='ksqrcl' id1=0 id2=0 name=   type=0 D7A495D8:007F9D3F    17   142 10444  12 ABORT TRANSACTION - xid: 0x0007.018.000001fe ??  PID 17 ??? TX resource?Enqueue Waiter linked List ???PID 24???,????KSL POST SENT ?? PID 24, ???ksqrcl???ENQUEUE LOCK ?PID 24??????KSL POST (KSL POST RCVD poster=17), ?ksqgtl???? TX-00070018-000001fe ?? ksqrcl??, ??PID 24???????? TX lock?USN ,??????? USN 3 XID 3.11.582 ,???acquire TX-0003000b-00000246 D7A49616:007F9D41    24   140 10005   3 KSL POST RCVD poster=17 loc='ksqrcl' id1=0 id2=0 name=   type=0 fac#=0 facpost=1 D7A4961C:007F9D42    24   140 10704  19 ksqgtl: SUCCESS D7A4967D:007F9D43    24   140 10704 117 ksqrcl: release TX-00070018-000001fe mode=X D7A496A5:007F9D44    24   140 10813   1 ktubnd: Bind usn 3 nax 1 nbx 0 lng 0 par 0 D7A496C2:007F9D45    24   140 10813   2 ktubnd: Txn Bound xid: 3.11.582 D7A496C7:007F9D46    24   140 10704  83 ksqgtl: acquire TX-0003000b-00000246 mode=X flags=GLOBAL|XACT why="contention" D7A496E4:007F9D47    24   140 10704  19 ksqgtl: SUCCESS ROW LOCK?Release ??????TX?ENQUEUE LOCK,?????????Process J ????????????, Process K??????????? ,Process K?????????,???row piece?lb??0×0 ,?????ITL,Process Z???ITL???????Process J????XID,?????Process J?????TX lock,PROCESS K ???TX resource?Enqueue Waiter Linked List?????X mode(exclusive)?enqueue lock? ???Process J??TX lock?,Process J?????TX resource?Enqueue Waiter Linked List ???Process K??????,??POST?????Process K? TX lock??????,???????row lock???????,?????????

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  • Store Varnish cache in hard disk

    - by Great Kuma
    Hello, The situation is: Im building PHP application, and need http caching. Varnish is great, and lots of people tell me that Varnish store the cached data in RAM. But I want it cached in hard disk. Is there any way to store the Varnish cached data in hard disk? thanks.

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  • Dovecot 2.x unix_listners

    - by Matthew Brown
    Could somebody be able to explain to me what the various unix_listners do in the Dovecot 2.x configuration (specifically 10-master.conf). Currently, for postfix to use to deliver mail, I have: service lmtp { unix_listener /var/spool/postfix/private/dovecot-lmtp { group = postfix mode = 0660 user = postfix } } and for auth I have: service auth { unix_listener /var/spool/postfix/private/auth { mode = 0666 } unix_listener auth-userdb { mode = 0666 user = vmail } } So what does each one specifically do? Also, does somebody know of a resource that can explain the mode setting?

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  • Firefox is very slow when establish SSL sessions

    - by yanglei
    Using wireshark, I discovered that Firefox v3.0 gets stuck every time before "client key exchange, change cipher spec" stage when establishing a SSL session. Specifically, it takes 0.8~1.8 second before Firefox send "Client Key Exchange" request. This is unacceptable since our application is HTTPS only. I tested this on IE6 and IE8, both works well. Any clues? [Update] Finally, I found the reason of 1 ~ 2 seconds stuck by displaying all captured packets in Wireshark. After the "server hello" stage, Firefox makes a request to ocsp.verisign.com combined with an additional DNS lookup for that domain. Firefox must wait the revocation status from OCSP before entering the next stage of SSL. Depends on whether DNS cache is in effect, this process takes 1 ~ 2 seconds. A interesting observation is that the IP packet contains "client key exchange" has a high possibility to get lost and thus a TCP retransmission is necessary. When this happens, the process can take 3 seconds at worst. I'm not sure if this is a coincidence or a bug. Anyway, here is the result from Wireshark: (delta-time) 0.369296 src-ip dst-ip TCP [ACK] Seq=161 Ack=2741 Win=65340 Len=0 2.538835 src-ip dst-ip TLSv1 Client Key Exchange, Change Cipher Spec, Finished 2.987034 src-ip dst-ip TLSv1 [TCP Retransmission] Client Key Exchange, Change Cipher Spec, Finished The difference between Firefox and IE is this: Firefox 3 enables OCSP checking by default where as IE only supports it. So, there is no problem with both IE6 and IE8. This is indeed a "certificate revoke" problem. Thanks

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