Bug #78718 Details about parallel dumping with mysqlpump

• Submitted: 6 Oct 2015 13:17
• Modified: 9 Oct 2015 14:15
• Reporter: Daniël van Eeden (OCA)
• Status: Closed
• Category: MySQL Server: Documentation
• Severity: S3 (Non-critical)
• Version: 5.7.9
• OS: Any
• CPU Architecture: Any
• Tags: mysqlpump, parallel

[6 Oct 2015 13:17] Daniël van Eeden

Description:
Page: https://dev.mysql.com/doc/refman/5.7/en/mysqlpump.html#mysqlpump-parallelism

This page doesn't (fully) answer these questions:
1. If multiple large table are dumped with mysqlpump: How are the tables merged in the result file (or stdout)? To me it looks like only one table can be written to disk/stdout at a time.

2. Is it possible to dump one table in parallel?

How to repeat:
Read docs

[6 Oct 2015 13:24] MySQL Verification Team

Thank you for the bug report.

[9 Oct 2015 14:10] Paul DuBois

1. INSERT statements for the tables are written in no particular order. Statements for different tables can be interspersed.

2. No.

[9 Oct 2015 14:15] Paul DuBois

Thank you for your bug report. This issue has been addressed in the documentation. The updated documentation will appear on our website shortly.

Updated text:

With parallelism enabled, it is possible for output from different
databases to be interleaved. For example, INSERT statements from
multiple tables dumped in parallel can be interleaved; the statements
are not written in any particular order. This does not affect
reloading because output statements qualify object names with
database names or are preceded by USE statements as required.

The granularity for parallelism is a single database object. For
example, a single table cannot be dumped in parallel using multiple
threads.