FYI - Here are some more counter results with/without the skip patch [1] applied.
This is the same test setup as before except now using *synchronous* pub/sub. ////////// Test setup: - using synchronous pub/sub - subscription is for the pgbench_history table - pgbench is run for 10 seconds - config for all the wal_sender/receiver timeout GUCs are just default values WITHOUT the skip-first patch applied ===================================== RUN #1 ------ LOG: Total records: 310 LOG: 24: 49 / 131 / 49: 8403 / 9270 LOG: 944: 1 / 0 / 1: 159693904 / 159693904 LOG: 8280: 1 / 2 / 2: 480 / 480 RUN #2 ------ LOG: Total records: 275 LOG: 24: 45 / 129 / 46: 8580 / 8766 LOG: 5392: 1 / 0 / 1: 160107248 / 160107248 RUN #3 ------ LOG: Total records: 330 LOG: 24: 50 / 144 / 51: 8705 / 8705 LOG: 3704: 1 / 0 / 1: 160510344 / 160510344 LOG: 8280: 1 / 2 / 2: 468 / 468 WITH the skip-first patch applied ================================= RUN #1 ------ LOG: Total records: 247 LOG: 24: 5 / 172 / 44: 3601700 / 3601700 LOG: 8280: 1 / 1 / 1: 1192 / 1192 RUN #2 ------ LOG: Total records: 338 LOG: 24: 8 / 199 / 55: 1335 / 1335 LOG: 7597: 1 / 1 / 1: 11712 / 11712 LOG: 8280: 1 / 1 / 2: 480 / 480 RUN #3 ------ LOG: Total records: 292 LOG: 24: 4 / 184 / 49: 719 / 719 ////////// As before there is a big % reduction of keepalives after the patch, except here there was never really much of a "flood" in the first place. ------ [1] https://www.postgresql.org/message-id/CAHut%2BPtyMBzweYUpb_QazVL6Uze2Yc5M5Ti2Xwee_eWM3Jrbog%40mail.gmail.com Kind Regards, Peter Smith. Fujitsu Australia
