Release version 0.5.0

commit for release 0.5.0

release v0.5.0-rc1

Commit for release 0.4.0

Release v0.4.1-rc2

[ARCTIC-1245][AMS] If the Optimize_task is in the commit process, the…

… MySQL connection is disconnected, let it retry next time (apache#1249)

* fix close_wait problem in limit query

* Retry when commit fails due to MySQL disconnection

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Co-authored-by: Chao He <[email protected]>

Commit for release 0.4.0

Release Arctic 0.4.0