Drizzle

Native Replication

Registered by David Shrewsbury on 2011-02-04

Implement native replication between Drizzle servers.

Using the InnoDB based transaction log, we will extract replication events from the log on the master and ship them to a slave server that will queue the events in a local table. The slave will then periodically extract the events from the table, apply them locally, then delete them from its queue.

Blueprint information

Status:: Complete

Approver:: David Shrewsbury

Priority:: High

Drafter:: David Shrewsbury

Direction:: Approved

Assignee:: David Shrewsbury

Definition:: Approved

Series goal:: Accepted for 7.0

Implementation:: Implemented

Milestone target:: 2011-03-14

Started by: David Shrewsbury on 2011-02-04

Completed by: David Shrewsbury on 2011-03-02

Related branches

Related bugs

Bug #711068: message size in DD table INNODB_REPLICATION_LOG is too small	Fix Released
Bug #716502: Need a way to permanently filter certain schemas from the replication stream	Fix Released
Bug #720433: 'replication' schema being used vs. actual schema for certain INSERTs with the slave-plugin	Fix Released
Bug #720501: starting slave with relative path or non existant slave.config-file does not error out	Fix Released
Bug #720819: Drizzle with slave plugin crashing when replicating certain rows of data	Fix Released
Bug #720886: Slave plugin showing difference from master in concurrent scenarios	Fix Released
Bug #720908: slave will not reconnect if initial connection to master is unsuccessful	Fix Released
Bug #723923: Make sleep intervals for slave plugin configurable	Fix Released

Sprints

Whiteboard

[Update 16 Feb 2011]

Slave plugin work complete. Needs a good amount of testing.

InnoDB replication log has tested solid.

Have now exposed the internal InnoDB replication log table through a D_D table. Only read operations on it are supported until we can have a permanent block on certain schemas/tables from the replication stream.

Performance regression bug (715174) still needs investigating.

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Good progress on the slave plugin. Applier thread reads from local table and applies changes locally. Still need a way to catch local execution errors, handle DDL properly, and record state information (last applied transaction, etc.).

Need to implement a version of an IO thread in the slave plugin. Plan is to just have a separate thread started by the slave plugin to connect to the master and transfer messages to a local table to be processed by a separate applier thread.

Need bug 711068 fixed (currently blocked by bug 646898). We can avoid the problem caused by bug 646898 by exposing the internal table and avoiding DATA_DICTIONARY altogether. This will also allow an admin to do maintenance on the internal table.

InnoDB replication log needs extensive testing. Blocked by bug 711068.

Need bug 715174 fixed/investigated.

(?)

Work Items

Dependency tree

* Blueprints in grey have been implemented.

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