RE: Big Performance drop of Exceptions in UDFs between V11.2 and 13.4

   >  -----Original Message-----
   >  From: Justin Pryzby <pryzby@telsasoft.com>
   >  Sent: Saturday, August 21, 2021 15:20
   >  To: Tom Lane <tgl@sss.pgh.pa.us>
   >  Cc: ldh@laurent-hasson.com; pgsql-performance@postgresql.org
   >  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@laurent-hasson.com" <ldh@laurent-hasson.com> 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
X64and 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
happeningwith the upgrade path I took? 

Thank you,
Laurent Hasson.