database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-11 10:01:57 +03:00
Code Activity

Add a GUC parameter seq_page_cost, and use that everywhere we formerly

Browse Source 
assumed that a sequential page fetch has cost 1.0.  This patch doesn't
in itself change the system's behavior at all, but it opens the door to
people adopting other units of measurement for EXPLAIN costs.  Also, if
we ever decide it's worth inventing per-tablespace access cost settings,
this change provides a workable intellectual framework for that.
This commit is contained in:
Tom Lane
2006-06-05 02:49:58 +00:00
parent a837851dc0
commit eed6c9ed7e
8 changed files with 243 additions and 187 deletions
Download Patch File Download Diff File Expand all files Collapse all files

88
src/backend/utils/misc/guc.c
View File

@ -10,7 +10,7 @@
* Written by Peter Eisentraut <peter_e@gmx.net>.
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.320 2006/05/21 20:10:42 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.321 2006/06/05 02:49:58 tgl Exp $
*
*--------------------------------------------------------------------
*/
@ -1594,6 +1594,52 @@ static struct config_int ConfigureNamesInt[] =
static struct config_real ConfigureNamesReal[] =
{
{
{"seq_page_cost", PGC_USERSET, QUERY_TUNING_COST,
gettext_noop("Sets the planner's estimate of the cost of a "
"sequentially fetched disk page."),
NULL
},
&seq_page_cost,
DEFAULT_SEQ_PAGE_COST, 0, DBL_MAX, NULL, NULL
},
{
{"random_page_cost", PGC_USERSET, QUERY_TUNING_COST,
gettext_noop("Sets the planner's estimate of the cost of a "
"nonsequentially fetched disk page."),
NULL
},
&random_page_cost,
DEFAULT_RANDOM_PAGE_COST, 0, DBL_MAX, NULL, NULL
},
{
{"cpu_tuple_cost", PGC_USERSET, QUERY_TUNING_COST,
gettext_noop("Sets the planner's estimate of the cost of "
"processing each tuple (row)."),
NULL
},
&cpu_tuple_cost,
DEFAULT_CPU_TUPLE_COST, 0, DBL_MAX, NULL, NULL
},
{
{"cpu_index_tuple_cost", PGC_USERSET, QUERY_TUNING_COST,
gettext_noop("Sets the planner's estimate of the cost of "
"processing each index entry during an index scan."),
NULL
},
&cpu_index_tuple_cost,
DEFAULT_CPU_INDEX_TUPLE_COST, 0, DBL_MAX, NULL, NULL
},
{
{"cpu_operator_cost", PGC_USERSET, QUERY_TUNING_COST,
gettext_noop("Sets the planner's estimate of the cost of "
"processing each operator or function call."),
NULL
},
&cpu_operator_cost,
DEFAULT_CPU_OPERATOR_COST, 0, DBL_MAX, NULL, NULL
},
{
{"effective_cache_size", PGC_USERSET, QUERY_TUNING_COST,
gettext_noop("Sets the planner's assumption about size of the disk cache."),
@ -1604,46 +1650,6 @@ static struct config_real ConfigureNamesReal[] =
&effective_cache_size,
DEFAULT_EFFECTIVE_CACHE_SIZE, 1, DBL_MAX, NULL, NULL
},
{
{"random_page_cost", PGC_USERSET, QUERY_TUNING_COST,
gettext_noop("Sets the planner's estimate of the cost of a nonsequentially "
"fetched disk page."),
gettext_noop("This is measured as a multiple of the cost of a "
"sequential page fetch. A higher value makes it more likely a "
"sequential scan will be used, a lower value makes it more likely an "
"index scan will be used.")
},
&random_page_cost,
DEFAULT_RANDOM_PAGE_COST, 0, DBL_MAX, NULL, NULL
},
{
{"cpu_tuple_cost", PGC_USERSET, QUERY_TUNING_COST,
gettext_noop("Sets the planner's estimate of the cost of processing each tuple (row)."),
gettext_noop("This is measured as a fraction of the cost of a "
"sequential page fetch.")
},
&cpu_tuple_cost,
DEFAULT_CPU_TUPLE_COST, 0, DBL_MAX, NULL, NULL
},
{
{"cpu_index_tuple_cost", PGC_USERSET, QUERY_TUNING_COST,
gettext_noop("Sets the planner's estimate of processing cost for each "
"index tuple (row) during index scan."),
gettext_noop("This is measured as a fraction of the cost of a "
"sequential page fetch.")
},
&cpu_index_tuple_cost,
DEFAULT_CPU_INDEX_TUPLE_COST, 0, DBL_MAX, NULL, NULL
},
{
{"cpu_operator_cost", PGC_USERSET, QUERY_TUNING_COST,
gettext_noop("Sets the planner's estimate of processing cost of each operator in WHERE."),
gettext_noop("This is measured as a fraction of the cost of a sequential "
"page fetch.")
},
&cpu_operator_cost,
DEFAULT_CPU_OPERATOR_COST, 0, DBL_MAX, NULL, NULL
},
{
{"geqo_selection_bias", PGC_USERSET, QUERY_TUNING_GEQO,