Обсуждение: pgsql: Exclude VACUUMs from RunningXactData
Exclude VACUUMs from RunningXactData GetRunningTransactionData() should ignore VACUUM procs because in some cases they are assigned xids. This could lead to holding back xmin via the route of passing the xid to standby and then having that hold back xmin on master via feedback. Backpatch to 9.1 needed, but will only do so on supported versions. Backpatch once proven on the buildfarm. Reported-by: Greg Stark Author: Simon Riggs Reviewed-by: Amit Kapila Discussion: https://postgr.es/m/CANP8+jJBYt=4PpTfiPb0UrH1_iPhzsxKH5Op_Wec634F0ohnAw@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/32ac7a118fc17f5baac1b370f50d759c30bee00a Modified Files -------------- src/backend/storage/ipc/procarray.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
Simon Riggs <simon@2ndQuadrant.com> writes:
> Exclude VACUUMs from RunningXactData
> GetRunningTransactionData() should ignore VACUUM procs because in some
> cases they are assigned xids.
Uh, what? Lazy vacuum shouldn't acquire an xid. If it does, that
would suggest it's running code that it's unsafe for
GetRunningTransactionData to ignore.
regards, tom lane
On 2018-06-07 16:24:30 -0400, Tom Lane wrote: > Simon Riggs <simon@2ndQuadrant.com> writes: > > Exclude VACUUMs from RunningXactData > > GetRunningTransactionData() should ignore VACUUM procs because in some > > cases they are assigned xids. > > Uh, what? Lazy vacuum shouldn't acquire an xid. If it does, that > would suggest it's running code that it's unsafe for > GetRunningTransactionData to ignore. Well, we currently do acquire an xid at the end when truncating (see [1]). But that still doesn't seem to make it the right thing to ignore these xids. Let's continue the discussion over there? Greetings, Andres Freund [1] http://archives.postgresql.org/message-id/20180607211918.h2cdja26ypriw2sm%40alap3.anarazel.de