diff options
Diffstat (limited to 'src/backend/commands/tablecmds.c')
| -rw-r--r-- | src/backend/commands/tablecmds.c | 90 |
1 files changed, 74 insertions, 16 deletions
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index 48ebd597c99..4a3c146faa0 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.177 2006/01/30 16:18:58 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.178 2006/03/03 03:30:52 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -527,26 +527,79 @@ RemoveRelation(const RangeVar *relation, DropBehavior behavior) * ExecuteTruncate * Executes a TRUNCATE command. * - * This is a multi-relation truncate. It first opens and grabs exclusive - * locks on all relations involved, checking permissions and otherwise - * verifying that the relation is OK for truncation. When they are all - * open, it checks foreign key references on them, namely that FK references - * are all internal to the group that's being truncated. Finally all - * relations are truncated and reindexed. + * This is a multi-relation truncate. We first open and grab exclusive + * lock on all relations involved, checking permissions and otherwise + * verifying that the relation is OK for truncation. In CASCADE mode, + * relations having FK references to the targeted relations are automatically + * added to the group; in RESTRICT mode, we check that all FK references are + * internal to the group that's being truncated. Finally all the relations + * are truncated and reindexed. */ void -ExecuteTruncate(List *relations) +ExecuteTruncate(TruncateStmt *stmt) { List *rels = NIL; + List *directRelids = NIL; ListCell *cell; + Oid relid; + Relation rel; - foreach(cell, relations) + /* + * Open and exclusive-lock all the explicitly-specified relations + */ + foreach(cell, stmt->relations) { RangeVar *rv = lfirst(cell); - Relation rel; - /* Grab exclusive lock in preparation for truncate */ rel = heap_openrv(rv, AccessExclusiveLock); + rels = lappend(rels, rel); + directRelids = lappend_oid(directRelids, RelationGetRelid(rel)); + } + + /* + * In CASCADE mode, suck in all referencing relations as well. This + * requires multiple iterations to find indirectly-dependent relations. + * At each phase, we need to exclusive-lock new rels before looking + * for their dependencies, else we might miss something. + */ + if (stmt->behavior == DROP_CASCADE) + { + List *relids = list_copy(directRelids); + + for (;;) + { + List *newrelids; + + newrelids = heap_truncate_find_FKs(relids); + if (newrelids == NIL) + break; /* nothing else to add */ + + foreach(cell, newrelids) + { + relid = lfirst_oid(cell); + rel = heap_open(relid, AccessExclusiveLock); + rels = lappend(rels, rel); + relids = lappend_oid(relids, relid); + } + } + } + + /* now check all involved relations */ + foreach(cell, rels) + { + rel = (Relation) lfirst(cell); + relid = RelationGetRelid(rel); + + /* + * If this table was added to the command by CASCADE, report it. + * We don't do this earlier because if we error out on one of the + * tables, it'd be confusing to list subsequently-added tables. + */ + if (stmt->behavior == DROP_CASCADE && + !list_member_oid(directRelids, relid)) + ereport(NOTICE, + (errmsg("truncate cascades to table \"%s\"", + RelationGetRelationName(rel)))); /* Only allow truncate on regular tables */ if (rel->rd_rel->relkind != RELKIND_RELATION) @@ -585,25 +638,30 @@ ExecuteTruncate(List *relations) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot truncate temporary tables of other sessions"))); - - /* Save it into the list of rels to truncate */ - rels = lappend(rels, rel); } /* - * Check foreign key references. + * Check foreign key references. In CASCADE mode, this should be + * unnecessary since we just pulled in all the references; but as + * a cross-check, do it anyway if in an Assert-enabled build. */ +#ifdef USE_ASSERT_CHECKING heap_truncate_check_FKs(rels, false); +#else + if (stmt->behavior == DROP_RESTRICT) + heap_truncate_check_FKs(rels, false); +#endif /* * OK, truncate each table. */ foreach(cell, rels) { - Relation rel = lfirst(cell); Oid heap_relid; Oid toast_relid; + rel = (Relation) lfirst(cell); + /* * Create a new empty storage file for the relation, and assign it as * the relfilenode value. The old storage file is scheduled for |