> -----Original Message----- > From: Justin Pryzby <pryzby@xxxxxxxxxxxxx> > Sent: Saturday, August 21, 2021 15:20 > To: Tom Lane <tgl@xxxxxxxxxxxxx> > Cc: ldh@xxxxxxxxxxxxxxxxxx; pgsql-performance@xxxxxxxxxxxxxx > Subject: Re: Big Performance drop of Exceptions in UDFs between V11.2 > and 13.4 > > On Sat, Aug 21, 2021 at 02:17:26PM -0400, Tom Lane wrote: > > "ldh@xxxxxxxxxxxxxxxxxx" <ldh@xxxxxxxxxxxxxxxxxx> writes: > > > So you mean that on average, the 4x overhead of exceptions is > around what you'd expect? > > > > Doesn't surprise me any, no. Exception recovery has to clean up after > > a wide variety of possible errors, with only minimal assumptions about > > what the system state had been. So it's expensive. More to the > > point, the overhead's been broadly the same for quite some time. > > > > > As for results in general, yes, your numbers look pretty uniform > across versions. On my end, comparing V11.2 vs V13.4 shows a much > different picture! > > > > I'm baffled why that should be so. I do not think any of the > > extensions you mention add any exception-recovery overhead, > especially > > not in sessions that haven't used them. > > Laurent, did you install binaries for v13.4 or compile it ? > > What about these ? > > SHOW shared_preload_libraries; > SHOW session_preload_libraries; > SHOW local_preload_libraries; > > Would you try to reproduce the issue with a fresh database: > CREATE DATABASE udftest; ... > > Or a fresh instance created with initdb. > > As I recall, you're running postgres under a windows VM - I'm not sure if > that's relevant. > > -- > Justin Hello Justin, - I used the standard installer from https://www.enterprisedb.com/downloads/postgres-postgresql-downloads for Windows X64 and upgraded from 13.3, which itself was pg_upgraded from 11.2. - Yes, windows VM on VMWARE. - No entries from shared_preload_libraries, session_preload_libraries or local_preload_libraries. - Version is "PostgreSQL 13.4, compiled by Visual C++ build 1914, 64-bit". - I created a new database and reran the scenarios without much of a change. - I think I am going to install a whole fresh new instance from scratch and see if there may have been some weird stuff happening with the upgrade path I took? Thank you, Laurent Hasson.
