Re: Logical replication keepalive flood - Mailing list pgsql-hackers

From Peter Smith
Subject Re: Logical replication keepalive flood
Date
Msg-id CAHut+PvFwY5D1Y-Pn9c9aXywG_qZqT2-WgFbpJEmZuH8rAbFNA@mail.gmail.com
Whole thread Raw
In response to Re: Logical replication keepalive flood  (Peter Smith <smithpb2250@gmail.com>)
List pgsql-hackers
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



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