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Showing entries 1 to 10 of 211 10 Older Entries

Displaying posts with tag: MySQL 5.6 (reset)

Create MySQL Index
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Indexes are separate data structures that provide alternate pathways to finding data. They can and do generally speed up the processing of queries and other DML commands, like the INSERT, UPDATE, REPLACE INTO, and DELETE statements. Indexes are also called fast access paths.

In the scope of the InnoDB Database Engine, the MySQL database maintains the integrity of indexes after you create them. The upside of indexes is that they can improve SQL statement performance. The downside is that they impose overhead on every INSERT, UPDATE, REPLACE INTO, and …

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Unexpected Memory Consumption for Bulk Index Creation in InnoDB (MySQL)
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In my last Hackathon, I worked on MyISAM vs InnoDB for data loading (LOAD DATA IN FILE) and bulk index creation.  My motivation was the following: knowing that some are still using MyISAM for this particular use-case, I wanted to verify/understand if/why InnoDB is slower than MyISAM.  I do not yet have complete results on this specific subject but I found some interesting things that

Advanced Query Tuning in MySQL 5.6 and MySQL 5.7 Webinar: Q&A
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Thank you for attending my July 22 webinar titled “Advanced Query Tuning in MySQL 5.6 and 5.7” (my slides and a replay available here). As promised here is the list of questions and my answers (thank you for your great questions).

Q: Here is the explain example:

mysql> explain extended select id, site_id from test_index_id where site_id=1
*************************** 1. row ***************************
           id: 1
  select_type: SIMPLE
        table: test_index_id
         type: ref …
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How much could you benefit from MySQL 5.6 parallel replication?
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I have heard this question quite often: “At busy times, our replicas start lagging quite frequently. We are using N schemas, so which performance boost could we expect from MySQL 5.6 parallel replication?” Here is a quick way to give you a rough estimate of the potential benefit.

General idea

In MySQL 5.6, parallelism is added at the schema level. So in theory, if you have N schemas and if you use N parallel threads, replication could be up to N times faster. This assumes at least 2 things:

  • Replication throughput scales linearly with the number of parallel threads.
  • Writes are …
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SSL/TLS Connections to Recent MySQL Servers in Java
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Recent changes to support better security by increasing strength of Diffie-Hellman cipher suites from 512-bit to 2048-bit were introduced to MySQL Server 5.7. While this change enhances security, it is an aggressive change in that 2048-bit DH ciphers are not universally supported. This has become a problem specifically for Java users, as only Java 8 JRE (currently) supports DH ciphers greater than 1024 bits. Making the problem more acute, this change was back-ported from MySQL Server 5.7 to the recent …

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MySQL 5.6.26 Overview and Highlights
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MySQL 5.6.26 was recently released (it is the latest MySQL 5.6, is GA), and is available for download here.

For this release, there are 3 “Functionality Added or Changed” items, 1 “Security Fix”, and 36 other bug fixes.

Out of those other 36 bugs, 13 are InnoDB, 1 Partitioning, 3 Replication, and 19 misc. (including 3 potentially crashing bug fixes, and 1 performance-related fix) Here are the ones of note:

  • Functionality Added/Changed: Replication: When using a multi-threaded slave, each worker thread has its own queue of …
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Inserting large rows in MySQL and MariaDB
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As the maximum storage size for a LONGBLOB in MySQL is 4GB and the maximum max_allowed_packet size is 1GB I was wondering how it is possible to use the full LONGBLOB.

So I started testing this. I wrote a Python script with MySQL Connector/Python and used MySQL Sandbox to bring up an instance of MySQl 5.6.25.

One of the first settings I had to change was max_allowed_packet, which was expected. I set it to 1GB.

The next setting was less expected, it was innodb_log_file_size. The server enforces that the transaction has to fit in 10% of the InnoDB log files. So I had to set it to 2 files of 5G to be able to …

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innodb_fast_checksum=1 and upgrading to MySQL 5.6
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The Percona version of MySQL has been such a good replacement for the generic MySQL version that many of the features and options that existed in Percona have been merged into the generic MySQL.

Innodb_fast_checksum was an option added to improve the performance of checksums.

The system variable was replaced by innodb_checksum_algorithm in 5.7.

Unfortunately, when you go to upgrade from Percona 5.x to Percona (or generic mysql) 5.6, an in-place upgrade will fail.

The error(s) will be …

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MySQL 5.6.25 Overview and Highlights
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MySQL 5.6.25 was recently released (it is the latest MySQL 5.6, is GA), and is available for download here.

For this release, there are 2 “Functionality Added or Changed” items of note:

  • Functionality Added/Changed: MySQL distributions now include an innodb_stress suite of test cases. Thanks to Mark Callaghan for the contribution. (Bug #76347)
  • Functionality Added/Changed: my_print_defaults now masks passwords. To display passwords in …
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Fun with Bugs #36 - Bugs fixed in MySQL 5.6.25
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Two days ago Oracle had released MySQL 5.6.25, so it's time to check what bugs reported by MySQL Community are fixed there. As usual, I'll mention both a bug reporter and engineer who verified the bug. Please, pay attention to fixes in replication and partitioning - if you use these features (or queries to INFORMATION_SCHEMA with a lot of complex tables in your database), please, consider upgrading ASAP.

The following …

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Showing entries 1 to 10 of 211 10 Older Entries

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