diff options
Diffstat (limited to 'src/backend/optimizer/util/plancat.c')
| -rw-r--r-- | src/backend/optimizer/util/plancat.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c index 7ffa11588d..aafaf843fc 100644 --- a/src/backend/optimizer/util/plancat.c +++ b/src/backend/optimizer/util/plancat.c @@ -322,7 +322,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent, * estimate_rel_size - estimate # pages and # tuples in a table or index * * If attr_widths isn't NULL, it points to the zero-index entry of the - * relation's attr_width[] cache; we fill this in if we have need to compute + * relation's attr_widths[] cache; we fill this in if we have need to compute * the attribute widths for estimation purposes. */ void @@ -435,8 +435,9 @@ estimate_rel_size(Relation rel, int32 *attr_widths, * get_rel_data_width * * Estimate the average width of (the data part of) the relation's tuples. - * If attr_widths isn't NULL, also store per-column width estimates into - * that array. + * + * If attr_widths isn't NULL, it points to the zero-index entry of the + * relation's attr_widths[] cache; use and update that cache as appropriate. * * Currently we ignore dropped columns. Ideally those should be included * in the result, but we haven't got any way to get info about them; and @@ -456,6 +457,14 @@ get_rel_data_width(Relation rel, int32 *attr_widths) if (att->attisdropped) continue; + + /* use previously cached data, if any */ + if (attr_widths != NULL && attr_widths[i] > 0) + { + tuple_width += attr_widths[i]; + continue; + } + /* This should match set_rel_width() in costsize.c */ item_width = get_attavgwidth(RelationGetRelid(rel), i); if (item_width <= 0) @@ -474,10 +483,11 @@ get_rel_data_width(Relation rel, int32 *attr_widths) /* * get_relation_data_width * - * External API for get_rel_data_width + * External API for get_rel_data_width: same behavior except we have to + * open the relcache entry. */ int32 -get_relation_data_width(Oid relid) +get_relation_data_width(Oid relid, int32 *attr_widths) { int32 result; Relation relation; @@ -485,7 +495,7 @@ get_relation_data_width(Oid relid) /* As above, assume relation is already locked */ relation = heap_open(relid, NoLock); - result = get_rel_data_width(relation, NULL); + result = get_rel_data_width(relation, attr_widths); heap_close(relation, NoLock); |