pg_stat_wal: Accumulate time as instr_time instead of microseconds In instr_time.h it is stated that:
* When summing multiple measurements, it's recommended to leave the * running sum in instr_time form (ie, use INSTR_TIME_ADD or * INSTR_TIME_ACCUM_DIFF) and convert to a result format only at the end. The reason for that is that converting to microseconds is not cheap, and can loose precision. Therefore this commit changes 'PendingWalStats' to use 'instr_time' instead of 'PgStat_Counter' while accumulating 'wal_write_time' and 'wal_sync_time'. Author: Nazir Bilal Yavuz <[email protected]> Reviewed-by: Andres Freund <[email protected]> Reviewed-by: Kyotaro Horiguchi <[email protected]> Reviewed-by: Melanie Plageman <[email protected]> Discussion: https://postgr.es/m/[email protected] Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/ca7b3c4c00042038ba9c282c4807e05c0a527e42 Modified Files -------------- src/backend/access/transam/xlog.c | 6 ++---- src/backend/storage/file/buffile.c | 6 ++---- src/backend/utils/activity/pgstat_wal.c | 31 ++++++++++++++++--------------- src/include/pgstat.h | 17 ++++++++++++++++- src/tools/pgindent/typedefs.list | 1 + 5 files changed, 37 insertions(+), 24 deletions(-)
