Re: [Proposal] Global temporary tables

2020年4月7日 下午6:22，Prabhat Sahu <prabhat.sahu@enterprisedb.com> 写道：

Thanks for review.

This parameter should support all types of writing of the bool type like parameter autovacuum_enabled.

So I fixed in global_temporary_table_v24-pg13.patch.

Thank you Wenjing for the new patch with the fix and the "VACUUM FULL GTT" support.

I have verified the above issue now its resolved.

Please check the below findings on VACUUM FULL.

postgres=# create global temporary table  gtt(c1 int) on commit preserve rows;
CREATE TABLE
postgres=# vacuum FULL ;
WARNING:  global temp table oldest FrozenXid is far in the past
HINT:  please truncate them or kill those sessions that use them.
VACUUM

This is expected,

This represents that the GTT FrozenXid is the oldest in the entire db, and dba should vacuum the GTT if he want to push the db datfrozenxid.

Also he can use function pg_list_gtt_relfrozenxids() to check which session has "too old” data and truncate them or kill the sessions.