feat concurrent chunk data

github / gh-ost

GitHub's Online Schema-migration Tool for MySQL

MIT License

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feat concurrent chunk data #1398

Open shaohk opened 3 months ago

shaohk commented 3 months ago

Description

This PR Supports concurrent copying of chunk blocks during each time slice of copying the existing data.

In case this PR introduced Go code changes:

[ ] contributed code is using same conventions as original code
[ ] script/cibuild returns with no formatting errors, build errors or unit test errors.

shaohk commented 3 months ago

MySQL insert ... select ... does not permit concurrent.

https://dev.mysql.com/doc/refman/5.7/en/insert-select.html

shaohk commented 3 months ago

When the unique index used for copying blocks includes an auto-increment column, concurrency is blocked on the auto-inc lock. If the unique index used does not include an auto-increment column, concurrency can proceed.