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Showing entries 1 to 10 of 822 10 Older Entries

Displaying posts with tag: innodb (reset)

Fun with Bugs #35 - Bugs fixed in MySQL 5.6.24
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I had not reviewed bug fixes in MySQL 5.6 for quite a some time, so I decided to check what bugs reported by MySQL Community were fixed in recently released MySQL 5.6.24. I'll mention both a bug reporter and engineer who verified the bug in the list below, because I still think that in MySQL world names should matter.

So, MySQL 5.6.24 includes fixes for the following bugs from …

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how innodb lost its advantage
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For years it was very easy to defend InnoDB’s advantage over competition – covering index reads were saving I/O operations and CPU everywhere, table space and I/O management allowed to focus on database and not on file systems or virtual memory behaviors, and for past few years InnoDB compression was the way to have highly efficient OLTP (or in our case – SGTP – Social Graph Transaction Processing) environments. Until one day (for some it came sooner, for others later)…

InnoDB team announced that it will change how it is going to do compression in the future and that old ways (that we rely on) will be all gone. I’m not exactly sure if there was any …

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InnoDB locks and deadlocks with or without index for different isolation level
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Recently, I was working on one of the issue related to locks and deadlocks with InnoDB tables and I found very interesting details about how InnoDB locks and deadlocks works with or without index for different Isolation levels.

Here, I would like to describe a small test case about how SELECT ..FOR UPDATE (with and without limit) behave with INSERT/UPDATE and with READ-COMMITED and REPEATABLE-READ Isolation levels. I’m creating a small table data_col with few records. Initially, this test case was written by …

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JSON Labs Release: Effective Functional Indexes in InnoDB
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In MySQL 5.7.6, we added a new feature called Generated Columns. In the initial work all Generated Columns were materialized, even virtual ones. This not only resulted in unnecessary disk space being used and disk I/O being done, but it also meant that any …

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Using gdb to understand what locks (and when) are really set by InnoDB. Part II.
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In the previous post we checked lock requests while executing INSERT INTO t ... SELECT FROM tt where there is an auto_increment column for which the value is generated in the destination table with default innodb_autoinc_lock_mode=1. Based on it I've reported Bug #76563 that is already verified.

Let's continue to study a special case of the statement mentioned above, INSERT INTO t ... SELECT FROM t, that …

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InnoDB 全文検索 : MeCab Parser
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(この記事は InnoDB Full-Text: MeCab ParserYoshiaki Yamasaki が翻訳したものです)

このブログ記事で紹介した一般的なCJK(中国語、日本語、韓国語)のサポートに加えて、私達は …

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More on (transactional) MySQL metadata locks
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Two years ago Ovais Tariq had explained in detail what kinds of problems existed before MySQL introduced metadata locks in 5.5.3 and how these locks help to prevent them. Still, some implications of metadata locking in MySQL remain unclear for users – DBAs and even software developers that target recent MySQL versions. I’ve decided to include a slide or two into the …

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Illustrating Primary Key models in InnoDB and their impact on disk usage
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On a recent engagement I worked with a customer who makes extensive use of UUID() values for their Primary Key and stores it as char(36), and their row count on this example table has grown to over 1 billion rows.

The table is INSERT-only (no UPDATEs or DELETEs), and the bulk of their retrieval are PK lookups. Lookups by PK were performing acceptably, but they were concerned with the space usage by the table as we were approaching 1TB (running with innodb_file_per_table=1 and Percona Server 5.5).

This schema model presents an increasing burden for backups since they use …

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Using gdb to understand what locks (and when) are really set by InnoDB. Part I.
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There is a story behind this post. To make it short, the detailed study presented here started when I noted old Bug #72748 in "No feedback" status few days ago. I considered this status totally wrong and started a discussion on Facebook about it (yes, this is what I usually do, I discuss handling of MySQL bugs in public).

The technical topic of this discussion (blaming aside) was the way AUTO-INC locks are set by InnoDB with default innodb_autoinc_lock_mode=1. …

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InnoDB 全文検索 : N-gram Parser
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(この記事は InnoDB Full-Text : N-gram ParserYoshiaki Yamasaki が翻訳したものです)

デフォルトのInnoDB全文検索パーサー(構文解析プログラム)は、空白がトークン(語句)もしくは単語の区切りとなっているラテン語ベースの言語に対して理想的です。しかし、個々の単語の区切り文字が存在せず、それぞれの単語は複数の文字で構成できる中国語・日本語・韓国語( …

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Showing entries 1 to 10 of 822 10 Older Entries

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