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Showing entries 1 to 10 of 159 10 Older Entries

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My top author list for Planet MySQL
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Who are the top individual authors of influential recent posts to planet MySQL?  The planet MySQL page includes a list of the top 20 authors as well as a list of the top 10 vendor blogs.  However, since posts to the vendor blogs make up at least 1/4 of all of the posts, and the authors of vendor blog posts are not included in the top author list, I decided to compute my own top author list.  I include the hidden authors from the vendor blogs when computing my top author list.

The first problem is to identify the hidden authors for posts from each vendor blog.  This requires that the author information be extracted …

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New Query Analysis Features in MONyog
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While looking to optimize your MySQL, you are needing to spot slow/bad queries at a glance and get deep insights about them with ease.

The latest update of MONyog brings new easier ways to find problem SQL in Real-Time, Wayback Machine and sniffer based Query Analyser using Performance Schema. Here is what’s new:

Query Execution Status and Full Table Scan Count
View success/failure status of every query executed and also the number of ‘full table scans’ for queries in a single glance.

The latest update also has an …



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mysql_real_connect is not thread safe
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The "mysql_real_connect" function is used by MySQL clients, including multi-threaded clients,  to connect to a MySQL server.  The "mysql_real_connect" function is allowed to be run by concurrent threads without application level serialization.  Unfortunately, the  …

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MySQL 5.7 InnoDB Versus the Thread Sanitizer
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InnoDB and the Thread Sanitizer do not work well together in MySQL 5.7.  There are hundreds of possible data races reported by the Thread Sanitizer in the InnoDB code for the simplest case of initializing the MySQL server and shutting it down.  Luckily, most of these data races are benign.  The problem of finding an interesting data race in the InnoDB software is similar to finding …

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MySQL 5.7 Performance Schema Versus the Thread Sanitizer
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This blog continues the investigation into possible data races in the MySQL server reported by the Thread Sanitizer.  The previous blog investigated several possible data races that were detected when the MySQL server is initialized.  This blog investigates three data races in the performance schema that are reported when the MySQL server is shut down.  The …

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MySQL 5.7 Initialization Versus the Thread Sanitizer
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The MySQL server is a large multi-threaded program primarily written in the C++ programming language.  Unfortunately,  data races and deadlocks in concurrent C++ programs are common.  Fortunately, the Thread Sanitizer can be used to find data races and deadlocks.  MySQL 5.7 does not support the Thread Sanitizer, but is is easy to …

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Uninitialized data problem in the LZMA compressor used by TokuFT
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The LZMA algorithm implemented by the xz compression software package is one of the compression algorithms used by TokuDB for MySQL and TokuMX for MongoDB. …

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MySQL 5.7 Versus the Address Sanitizer
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MySQL 5.7 supports the Address Sanitizer, which checks for several memory related software errors including memory leaks.  It is really nice to see support for the Address Sanitizer built into MySQL.  Unfortunately, when running the mysql tests included in MySQL 5.7.9, the Address Sanitizer reports several memory leaks, which causes some of  the tests to fail.  Here are some of the …

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Advanced MySQL Server Auditing
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We remember when we first started auditing MySQL servers, there were very few tools available.  In one of our early big gigs, we were battling serious performance issues for a client.  At the time, tuning-primer.sh was about the only tool available that could be used to diagnose performance bottlenecks.  Fortunately, with a lot of manual interpolation of the raw data it presented, we were able to find the issue with the server and suggest how to resolve them.  For that we are very thankful.  It was a first step in analyzing MySQL status variables, minimizing the number of formulas to learn and calculate by hand.  Obviously …

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TokuBackup Versus the Sanitizers
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Percona recently open sourced TokuBackup, a library that may be used to take a snapshot of a set of files while these files are being changed by a running application like MySQL or MongoDB.  Making TokuBackup open source allows a larger set of users to improve and extend the software.  This blog describes how the Address Sanitizer and Thread Sanitizer found bugs in the TokuBackup …

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Showing entries 1 to 10 of 159 10 Older Entries

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