On Tue, 1 Nov 2022 at 08:55, Julien Tachoires <jul...@gmail.com> wrote: > > > > 4. Test results with transaction 1 > > > > > > TPS vs number of sub-transaction > > > > > > nsubx HEAD patched > > > -------------------- > > > 0 441109 439474 > > > 8 439045 438103 > > > 16 439123 436993 > > > 24 436269 434194 > > > 32 439707 437429 > > > 40 439997 437220 > > > 48 439388 437422 > > > 56 439409 437210 > > > 64 439748 437366 > > > 72 92869 434448 > > > 80 66577 434100 > > > 88 61243 434255 > > > 96 57016 434419 > > > 104 52132 434917 > > > 112 49181 433755 > > > 120 46581 434044 > > > 128 44067 434268 > > > > > > Perf profiling on HEAD with 80 sub-transactions: > > > Overhead Symbol > > > 51.26% [.] LWLockAttemptLock > > > 24.59% [.] LWLockRelease > > > 0.36% [.] base_yyparse > > > 0.35% [.] PinBuffer > > > 0.34% [.] AllocSetAlloc > > > 0.33% [.] hash_search_with_hash_value > > > 0.22% [.] LWLockAcquire > > > 0.20% [.] UnpinBuffer > > > 0.15% [.] SimpleLruReadPage_ReadOnly > > > 0.15% [.] _bt_compare > > > > > > Perf profiling on patched with 80 sub-transactions: > > > Overhead Symbol > > > 2.64% [.] AllocSetAlloc > > > 2.09% [.] base_yyparse > > > 1.76% [.] hash_search_with_hash_value > > > 1.62% [.] LWLockAttemptLock > > > 1.26% [.] MemoryContextAllocZeroAligned > > > 0.93% [.] _bt_compare > > > 0.92% [.] expression_tree_walker_impl.part.4 > > > 0.84% [.] SearchCatCache1 > > > 0.79% [.] palloc > > > 0.64% [.] core_yylex > > > > > > 5. Test results with transaction 2 > > > > > > nsubx HEAD patched > > > -------------------- > > > 0 440145 443816 > > > 8 438867 443081 > > > 16 438634 441786 > > > 24 436406 440187 > > > 32 439203 442447 > > > 40 439819 443574 > > > 48 439314 442941 > > > 56 439801 443736 > > > 64 439074 441970 > > > 72 439833 444132 > > > 80 148737 439941 > > > 88 413714 443343 > > > 96 251098 442021 > > > 104 70190 443488 > > > 112 405507 438866 > > > 120 177827 443202 > > > 128 399431 441842 > > > > > > From the performance point of view, this patch clearly fixes the > > > dramatic TPS collapse shown in these tests. > > > > I think these are really promising results. Although the perf result > > shows that the bottleneck on the SLRU is no more there with the patch, > > I think it would be nice to see the wait event as well. > > Please find attached samples returned by the following query when > testing transaction 1 with 80 subxacts: > SELECT wait_event_type, wait_event, locktype, mode, database, > relation, COUNT(*) from pg_stat_activity AS psa JOIN pg_locks AS pl ON > (psa.pid = pl.pid) GROUP BY 1, 2, 3, 4, 5, 6 ORDER BY 7 DESC;
These results are compelling, thank you. Setting this to Ready for Committer. -- Simon Riggs http://www.EnterpriseDB.com/
