we have hit a serious performance regression going from 10.23 → 16.4 as far as tds_fdw (MS SQL) FDW is concerned. To cut the long story short, I recreated the good fast “old” (pgsql 10) setup on the same vm as the slow “new” (pgsql 16). Here is the bug report on github :
All environment on the two pgsql clusters is shared (freetds version, tds_fdw, gcc, llvm). Only thing differs are pgsql versions. The speed on the old pgsql 10.23 is about 10 to 20 times higher than pgsql 16.4 . Setting client_min_messages TO debug3 does yield identical output on the two systems.
The new pgsql 16.4 shows 100% CPU usage during the query execution.
I know we are pretty much alone with this, but it would be very nice if anyone could help, see smth we are missing or guide us via the right path.
https://github.com/tds-fdw/tds_fdw/issues/371
All environment on the two pgsql clusters is shared (freetds version, tds_fdw, gcc, llvm). Only thing differs are pgsql versions. The speed on the old pgsql 10.23 is about 10 to 20 times higher than pgsql 16.4 .
Setting client_min_messages TO debug3 does yield identical output on the two systems.
The new pgsql 16.4 shows 100% CPU usage during the query execution.
I know we are pretty much alone with this, but it would be very nice if anyone could help, see smth we are missing or guide us via the right path.