diff options
Diffstat (limited to 'src/backend/optimizer/path/costsize.c')
| -rw-r--r-- | src/backend/optimizer/path/costsize.c | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c index fcf462b83eb..99ee42cf8c7 100644 --- a/src/backend/optimizer/path/costsize.c +++ b/src/backend/optimizer/path/costsize.c @@ -18,7 +18,7 @@ * Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/costsize.c,v 1.45 1999/08/22 20:14:41 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/costsize.c,v 1.46 1999/11/23 20:06:54 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -59,6 +59,7 @@ bool _enable_sort_ = true; bool _enable_nestloop_ = true; bool _enable_mergejoin_ = true; bool _enable_hashjoin_ = true; +bool _enable_tidscan_ = true; Cost _cpu_page_weight_ = _CPU_PAGE_WEIGHT_; Cost _cpu_index_page_weight_ = _CPU_INDEX_PAGE_WEIGHT_; @@ -175,6 +176,29 @@ cost_index(Oid indexid, } /* + * cost_tidscan + * Determines and returns the cost of scanning a relation using tid-s. + * + * disk = number of tids + * cpu = *CPU-PAGE-WEIGHT* * number_of_tids + * + * Returns a flonum. + * + */ +Cost +cost_tidscan(List *tideval) +{ + Cost temp = 0; + + if (!_enable_tidscan_) + temp += _disable_cost_; + + temp += (1.0 + _cpu_page_weight_) * length(tideval); + + return temp; +} + +/* * cost_sort * Determines and returns the cost of sorting a relation by considering * the cost of doing an external sort: XXX this is probably too low |