diff options
Diffstat (limited to 'src/backend/optimizer/path/costsize.c')
| -rw-r--r-- | src/backend/optimizer/path/costsize.c | 43 |
1 files changed, 18 insertions, 25 deletions
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c index b718f8fea18..0f26dc78722 100644 --- a/src/backend/optimizer/path/costsize.c +++ b/src/backend/optimizer/path/costsize.c @@ -42,7 +42,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/costsize.c,v 1.61 2000/05/31 00:28:22 petere Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/costsize.c,v 1.62 2000/06/18 22:44:06 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -55,10 +55,15 @@ #include "miscadmin.h" #include "optimizer/clauses.h" #include "optimizer/cost.h" -#include "optimizer/internal.h" #include "utils/lsyscache.h" +/* + * The length of a variable-length field in bytes (stupid estimate...) + */ +#define _DEFAULT_ATTRIBUTE_WIDTH_ 12 + + #define LOG2(x) (log(x) / 0.693147180559945) #define LOG6(x) (log(x) / 1.79175946922805) @@ -114,29 +119,17 @@ cost_seqscan(Path *path, RelOptInfo *baserel) if (!enable_seqscan) startup_cost += disable_cost; - /* disk costs */ - if (lfirsti(baserel->relids) < 0) - { - - /* - * cost of sequentially scanning a materialized temporary relation - */ - run_cost += _NONAME_SCAN_COST_; - } - else - { - - /* - * The cost of reading a page sequentially is 1.0, by definition. - * Note that the Unix kernel will typically do some amount of - * read-ahead optimization, so that this cost is less than the - * true cost of reading a page from disk. We ignore that issue - * here, but must take it into account when estimating the cost of - * non-sequential accesses! - */ - run_cost += baserel->pages; /* sequential fetches with cost - * 1.0 */ - } + /* + * disk costs + * + * The cost of reading a page sequentially is 1.0, by definition. + * Note that the Unix kernel will typically do some amount of + * read-ahead optimization, so that this cost is less than the + * true cost of reading a page from disk. We ignore that issue + * here, but must take it into account when estimating the cost of + * non-sequential accesses! + */ + run_cost += baserel->pages; /* sequential fetches with cost 1.0 */ /* CPU costs */ cpu_per_tuple = cpu_tuple_cost + baserel->baserestrictcost; |