Skip redundant anti-wraparound vacuums An anti-wraparound vacuum has to be by definition aggressive as it needs to work on all the pages of a relation. However it can happen that due to some concurrent activity an anti-wraparound vacuum is marked as non-aggressive, which makes it redundant with a previous run, and it is actually useless as an anti-wraparound vacuum should process all the pages of a relation. This commit makes such vacuums to be skipped.
An anti-wraparound vacuum not aggressive can be found easily by mixing low values of autovacuum_freeze_max_age (to control anti-wraparound) and autovacuum_freeze_table_age (to control the aggressiveness). 28a8fa9 has added some extra logging printing all the possible combinations of anti-wraparound and aggressive vacuums, which now gets simplified as an anti-wraparound vacuum also non-aggressive gets skipped. Per discussion mainly between Andrew Dunstan, Robert Haas, Álvaro Herrera, Kyotaro Horiguchi, Masahiko Sawada, and myself. Author: Kyotaro Horiguchi, Michael Paquier Reviewed-by: Andrew Dunstan, Álvaro Herrera Discussion: https://postgr.es/m/20180914153554.562muwr3uwujno75@alvherre.pgsql Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/2aa6e331ead7f3ad080561495ad4bd3bc7cd8913 Modified Files -------------- src/backend/access/heap/vacuumlazy.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-)