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MySQL sys 1.3.0 released – The Facepalm Release
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With a last minute change to the host_summary_by_stages view for the 1.2.0 release of the sys schema, I managed to break the views without noticing it.

So, in the shortest release cycle for the sys schema ever (less than 24 hours), 1.3.0 has now been released.

This comes with a bonus though, there was also a new view that was contributed by Jesper Wisborg Krogh waiting to be merged as well, so I’ve added that to the 1.3.0 version (hence the 1.3.0 instead of 1.2.1).

This is the innodb_lock_waits view, which shows all sessions that are waiting for a lock within InnoDB, as well as the details of who is blocking them, here’s an example

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Monitoring progress and temporal memory usage of Online DDL in InnoDB
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Introduction

Online DDL is a new feature in MariaDB 10.0. Online DDL is processed through below 4 tasks in sequence.

  • InnoDB::ha_prepare_inplace_alter_table(..)
  • InnoDB::ha_inplace_alter_table(..)
  • InnoDB::ha_commit_inplace_alter_table(..)
  • mysql_rename_table(..)
  • InnoDB storage engine allocates temporal memory buffer for transaction logging in phase 1 where row changes during this phase are logged. Size of this buffer is at start sort_buffer_size and it can be grown up to innodb_online_alter_log_max size. During phase 2 thread processing the ALTER statement will copy old table’s rows to a new altered table. After this MariaDB will take exclusive lock for target table and applies row log buffer to the new altered table.

    This introduces a new unpredictable failure case row log buffer overflow. MariaDB

      [Read more...]
    Pseudo GTID, Row Based Replication
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    This post continues Pseudo GTID, in a series of posts describing an alternative to using MySQL GTIDs.

    The solution offered in the last post does not work too well for row based replication. The binary log entries for the INSERT statement look like this:

    # at 1020
    # at 1074
    #141020 12:36:21 server id 1  end_log_pos 1074  Table_map: `test`.`pseudo_gtid` mapped to number 33
    #141020 12:36:21 server id 1  end_log_pos 1196  Update_rows: table id 33 flags: STMT_END_F
    
    BINLOG '
    lddEVBMBAAAANgAAADIEAAAAACEAAAAAAAEABHRlc3QAC3BzZXVkb19ndGlkAAMDBw8CQAAE
    lddEVBgBAAAAegAAAKwEAAAAACEAAAAAAAEAA///+AEAAACL10RUJDg2ZmRhMDk1LTU4M2MtMTFl
    NC05NzYyLTNjOTcwZWEzMWVhOPgBAAAAlddEVCQ4Y2YzOWMyYy01ODNjLTExZTQtOTc2Mi0zYzk3
    MGVhMzFlYTg=
    '/*!*/;
    

    Where's our unique value? Encoded within

      [Read more...]
    MariaDB 10.1.1: FLUSH and SHOW for plugins
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    One of the most popular plugin types both in MariaDB and MySQL is INFORMATION_SCHEMA plugin type. INFORMATION_SCHEMA plugins add new tables to the INFORMATION_SCHEMA. There are lots of INFORMATION_SCHEMA plugins, because they can be used to show just anything to the user and are very easy to write.

    MariaDB 10.1.1 comes with nine INFORMATION_SCHEMA plugin:

    • Feedback — shows the anonymised server usage information and can optionally send it to the configured url.
    • Locales — lists compiled-in server locales, implemented by Roberto Spadim
    • METADATA_LOCK_INFO — Lists metadata locks in the server. Implemented by Kentoku Shiba
      [Read more...]
    Shinguz: Get rid of wrongly deleted InnoDB tables
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    Taxonomy upgrade extras: BackupRestoreRecoveryinnodbtable

    Precaution: Before you try this out on your production system do a BACKUP first! FromDual Backup Manager can help you with this.

    Situation

    A MySQL user has delete its InnoDB table files for example like this:

    shell> rm -f $datadir/test/test.*

    Analysis

    We do some analysis first:

    mysql> DROP TABLE test;
    ERROR 1051 (42S02): Unknown table 'test'
    
    mysql> CREATE TABLE test (id INT) ENGINE =
      [Read more...]
    MySQL sys version 1.2.0 released
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    MySQL sys version 1.2.0 has just been released.

    All views now work with MySQL 5.7.5, and the ONLY_FULL_GROUP_BY changes.

    There is also a new script available (generate_sql_file.sh) that will allow RDS users to easily generate a single SQL file, using a specified user, that can be loaded in to an RDS instance. See the README for details on how to use that.

    Here’s a full summary of the other changes:

    Backwards Incompatible Changes

    • The host_summary_by_stages and user_summary_by_stages wait_sum and wait_avg
      [Read more...]
    MySQL Crash-safe replication, Binlog Servers and Percona Live London
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    I just publish a post on the Booking.com blog: http://blog.booking.com/better_crash_safe_replication_for_mysql.html  Spoiler: it uses Binlog Servers.

    This is also the opportunity to tell you that I will be at Percona Live London at the beginning of November, and that I will give a talk about Binlog Servers: High Availability, Disaster Recovery and Extreme Read Scaling using Binlog Servers.  I will not talk too much about Binlog Server for crash-safe replication, but I will present a new use-case for Binlog Servers that I did not blog about yet.  I am looking forward to meet you there.
    libAttchSQL Hits First GA!
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    We have come a long way since the first code was put down for libAttachSQL on the 4th July. It has been a fantastic project to work on so I am very pleased to announce our first GA release.

    For those who haven't seen it so far libAttachSQL is a non-blocking, lightweight C API for MySQL servers. It is Apache 2.0 licensed so is compatible with most Open Source and commercial licensing. HP's Advanced Technology Group saw a need in this field not just for HP itself but for other companies and projects too.

    As for the GA release itself, there are not many changes over the RC release beyond stability fixes. A full list can be seen in the version history documentation.

    In addition to the GA release we have recently had a driver for

      [Read more...]
    Why I moved my Joomla website to MariaDB
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    Wed, 2014-10-22 09:02svetoslavsavov

    Next time you want to build a fast, well-optimized website, don't forget the database system. Many content management systems (CMS) let you choose a relational database management system (RDBMS) to use on the back end. MySQL, famous for its stability and security, is a popular choice; in addition to its numerous features, it has a large community, many contributors, and good documentation. However, MySQL is now owned by Oracle, and its future is not clear, which makes MariaDB, an application compatible database system, an excellent alternative.

    Joomla, a popular CMS, is written in PHP and by default uses MySQL as its database system. Since MariaDB can provide improved functionality, performance, and stability, you might

      [Read more...]
    Pseudo GTID
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    Pseudo GTID is a method to implement a GTID-like solution where slaves are easily connected to one another. This blog post and the following ones will describe work in progress (some 80% completed), where simulation of GTID makes for a good enough basis for refactoring replication topologies. I'm coding this in orchestrator, which already provides a substantial infrastructure support for this.

    The final goal: orchestrator will allow you to move a slave below another, using only the data available by those two slaves. The usage is obvious:

    • Easy master failover (master dead? Orchestrator will choose the most advanced slave to promote and make it master of its siblings)
    • Slave promotion in complex topologies (with
      [Read more...]
    Showing entries 1 to 10 of 33318 10 Older Entries

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