Avoid passing zero as a value for vacuum_cost_limit, because it's not a valid

value for the vacuum code.  Instead, make zero signify getting the value from a
higher level configuration facility, just like -1 in the original coding.  We
still document that -1 is the value that disables the feature, to avoid
confusing the user unnecessarily.

Reported by Galy Lee in <200705310914.l4V9E6JA094603@wwwmaster.postgresql.org>;
per subsequent discussion.
This commit is contained in:
Alvaro Herrera 2007-06-08 21:09:49 +00:00
parent 4213e5f0db
commit 2b438c12cc
2 changed files with 13 additions and 7 deletions

View File

@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.153 2007/06/05 21:31:03 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.154 2007/06/08 21:09:49 alvherre Exp $ -->
<!--
Documentation of the system catalogs, directed toward PostgreSQL developers
-->
@ -1339,7 +1339,7 @@
be used for this particular value. Observe that the
<structfield>vac_cost_delay</> variable inherits its default value from the
<xref linkend="guc-autovacuum-vacuum-cost-delay"> configuration parameter,
or from <varname>vacuum_cost_delay</> if the former is set to a negative
or from <xref linkend="guc-vacuum-cost-delay"> if the former is set to a negative
value. The same applies to <structfield>vac_cost_limit</>.
Also, autovacuum will ignore attempts to set a per-table
<structfield>freeze_max_age</> larger than the system-wide setting (it can only be set

View File

@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.47 2007/05/30 20:11:57 tgl Exp $
* $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.48 2007/06/08 21:09:49 alvherre Exp $
*
*-------------------------------------------------------------------------
*/
@ -1548,7 +1548,11 @@ static void
autovac_balance_cost(void)
{
WorkerInfo worker;
int vac_cost_limit = (autovacuum_vac_cost_limit >= 0 ?
/*
* note: in cost_limit, zero also means use value from elsewhere, because
* zero is not a valid value.
*/
int vac_cost_limit = (autovacuum_vac_cost_limit > 0 ?
autovacuum_vac_cost_limit : VacuumCostLimit);
int vac_cost_delay = (autovacuum_vac_cost_delay >= 0 ?
autovacuum_vac_cost_delay : VacuumCostDelay);
@ -2140,12 +2144,14 @@ table_recheck_autovac(Oid relid)
* there is a tuple in pg_autovacuum, use it; else, use the GUC
* defaults. Note that the fields may contain "-1" (or indeed any
* negative value), which means use the GUC defaults for each setting.
* In cost_limit, the value 0 also means to use the value from
* elsewhere.
*/
if (avForm != NULL)
{
vac_cost_limit = (avForm->vac_cost_limit >= 0) ?
vac_cost_limit = (avForm->vac_cost_limit > 0) ?
avForm->vac_cost_limit :
((autovacuum_vac_cost_limit >= 0) ?
((autovacuum_vac_cost_limit > 0) ?
autovacuum_vac_cost_limit : VacuumCostLimit);
vac_cost_delay = (avForm->vac_cost_delay >= 0) ?
@ -2158,7 +2164,7 @@ table_recheck_autovac(Oid relid)
}
else
{
vac_cost_limit = (autovacuum_vac_cost_limit >= 0) ?
vac_cost_limit = (autovacuum_vac_cost_limit > 0) ?
autovacuum_vac_cost_limit : VacuumCostLimit;
vac_cost_delay = (autovacuum_vac_cost_delay >= 0) ?