diff options
Diffstat (limited to 'src/backend/optimizer/util/plancat.c')
| -rw-r--r-- | src/backend/optimizer/util/plancat.c | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c index 25545029d7a..f9d0d67aa75 100644 --- a/src/backend/optimizer/util/plancat.c +++ b/src/backend/optimizer/util/plancat.c @@ -974,11 +974,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths, /* it has storage, ok to call the smgr */ curpages = RelationGetNumberOfBlocks(rel); - /* coerce values in pg_class to more desirable types */ - relpages = (BlockNumber) rel->rd_rel->relpages; - reltuples = (double) rel->rd_rel->reltuples; - relallvisible = (BlockNumber) rel->rd_rel->relallvisible; - /* report estimated # pages */ *pages = curpages; /* quick exit if rel is clearly empty */ @@ -988,6 +983,7 @@ estimate_rel_size(Relation rel, int32 *attr_widths, *allvisfrac = 0; break; } + /* coerce values in pg_class to more desirable types */ relpages = (BlockNumber) rel->rd_rel->relpages; reltuples = (double) rel->rd_rel->reltuples; @@ -1006,12 +1002,12 @@ estimate_rel_size(Relation rel, int32 *attr_widths, } /* estimate number of tuples from previous tuple density */ - if (relpages > 0) + if (reltuples >= 0 && relpages > 0) density = reltuples / (double) relpages; else { /* - * When we have no data because the relation was truncated, + * If we have no data because the relation was never vacuumed, * estimate tuple width from attribute datatypes. We assume * here that the pages are completely full, which is OK for * tables (since they've presumably not been VACUUMed yet) but @@ -1059,6 +1055,7 @@ estimate_rel_size(Relation rel, int32 *attr_widths, break; case RELKIND_FOREIGN_TABLE: /* Just use whatever's in pg_class */ + /* Note that FDW must cope if reltuples is -1! */ *pages = rel->rd_rel->relpages; *tuples = rel->rd_rel->reltuples; *allvisfrac = 0; |