Re: Add SPLIT PARTITION/MERGE PARTITIONS commands

> I didn't read the patch, but what lock level does that place on the
> partitioned table? Anything more than ACCESS SHARE?

Current patch locks a partitioned table with ACCESS EXCLUSIVE lock.
Unfortunately only this lock guarantees that other session can not work
with partitions that are splitting or merging.

I want add CONCURRENTLY mode in future. With this mode partitioned table
during SPLIT/MERGE operation will be locked with SHARE UPDATE EXCLUSIVE
(as ATTACH/DETACH PARTITION commands in CONCURRENTLY mode).
But in this case queries from other sessions that want to work with
partitions that are splitting/merging at this time should receive an
error (like "Partition data is moving. Repeat the operation later")
because old partitions will be deleted at the end of SPLIT/MERGE operation.
I hope exists a better solution, but I don't know it now...

--
With best regards,
Dmitry Koval

Postgres Professional: http://postgrespro.com