create_time_partitions and drop_old_time_partitions with less lock.

[icefairy]

DESCRIPTION: PR description that will go into the change log, up to 78 characters from:https://www.postgresql.org/docs/14/sql-createtable.html

Note that creating a partition using PARTITION OF requires taking an ACCESS EXCLUSIVE lock on the parent partitioned table. Likewise, dropping a partition with DROP TABLE requires taking an ACCESS EXCLUSIVE lock on the parent table. It is possible to use ALTER TABLE ATTACH/DETACH PARTITION to perform these operations with a weaker lock, thus reducing interference with concurrent operations on the partitioned table.

[icefairy]

@microsoft-github-policy-service agree

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 89.68%. Comparing base (f424268) to head (7e12c7d). Report is 22 commits behind head on main.

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Additional details and impacted files

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- Coverage   89.68%   89.68%   -0.01%     
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  Files         282      283       +1     
  Lines       60420    60428       +8     
  Branches     7523     7525       +2     
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+ Hits        54187    54193       +6     
- Misses       4079     4082       +3     
+ Partials     2154     2153       -1     

[JelteF]

Thank you for the contribution. This seems like a really nice improvement. For it to actually do something you have to create the relevant 12.2-1.sql files by copying latest.sql. See here for details: https://github.com/citusdata/citus/blob/main/CONTRIBUTING.md#changing-or-creating-functions

[icefairy]

done

[JelteF]

Ah, sorry I guess I wasn't clear before. You shouldn't update the old sql files. You should create:

• src/backend/distributed/sql/udfs/create_time_partitions/12.1-1.sql
• src/backend/distributed/sql/udfs/drop_old_time_partitions/12.1-1.sql

And #include those in: src/backend/distributed/sql/citus--12.0-1--12.1-1.sql

And do the reverse includes in: src/backend/distributed/sql/downgrades/citus--12.1-1--12.0-1.sql

[icefairy]

I think it's no need to modify downgrades script yes?

[JelteF]

I'm sorry, I messed up the version numbers in my previous message. Corrected below:

You shouldn't update the old sql files. You should create:

• src/backend/distributed/sql/udfs/create_time_partitions/12.2-1.sql
• src/backend/distributed/sql/udfs/drop_old_time_partitions/12.2-1.sql

And #include those in: src/backend/distributed/sql/citus--12.1-1--12.2-1.sql

And do the reverse includes in: src/backend/distributed/sql/downgrades/citus--12.2-1--12.1-1.sql

[icefairy]

file renamed

[JelteF]

You didn't do this part yet:

And #include those in: src/backend/distributed/sql/citus--12.1-1--12.2-1.sql

And do the reverse includes in: src/backend/distributed/sql/downgrades/citus--12.2-1--12.1-1.sql

And you also need to update the latest.sql files to be the same content as the new 12.2-1.sql files.

Finally, could you undo the removal of the trailing new line in these files. No changes should be necessary to these files at all:

• src/backend/distributed/sql/udfs/create_time_partitions/10.2-1.sql
• src/backend/distributed/sql/udfs/drop_old_time_partitions/12.0-1.sql