[MDEV-18368] MySQL already can do parallel queries, when MariaDB Created: 2019-01-24  Updated: 2020-12-20  Resolved: 2020-11-10

Status: Closed
Project: MariaDB Server
Component/s: Optimizer
Fix Version/s: N/A

Type: Task Priority: Major
Reporter: Philip orleans Assignee: Unassigned
Resolution: Duplicate Votes: 0
Labels: None

Issue Links:
Duplicate
is duplicated by MDEV-6096 Ideas about parallel query execution Open
Relates
relates to MDEV-21291 Support Parallel Query Execution Closed

 Description   

The latest version of MySQL can do parallel queries, albeit only for select count(*) type queries. Nevertheless, this is a huge improvement. I have a RocksDB table with 1.9 BN records, and to do a select count(*) takes hours.

Can somebody look into this?

 Comments   
Comment by Igor Babaev [ 2019-03-28 ]

Philip,
Percona Server also support RocksDB. At the same time Percona Server is based on MySQL code base.

Comment by Rick James [ 2020-12-20 ]

There are so many variables (caching, competing threads, unbalanced BTrees, etc) that I would not worry about how "balanced" the chunks are. I would, instead, reach down the BTree only a level or two to figure out how to split the table.

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