diff options
Diffstat (limited to 'src/backend/commands/tablecmds.c')
| -rw-r--r-- | src/backend/commands/tablecmds.c | 161 |
1 files changed, 160 insertions, 1 deletions
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index 421bc28727e..2ec3fc50145 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -388,6 +388,8 @@ static ObjectAddress ATExecAddIdentity(Relation rel, const char *colName, static ObjectAddress ATExecSetIdentity(Relation rel, const char *colName, Node *def, LOCKMODE lockmode); static ObjectAddress ATExecDropIdentity(Relation rel, const char *colName, bool missing_ok, LOCKMODE lockmode); +static void ATPrepDropExpression(Relation rel, AlterTableCmd *cmd, bool recursing); +static ObjectAddress ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMODE lockmode); static ObjectAddress ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newValue, LOCKMODE lockmode); static ObjectAddress ATExecSetOptions(Relation rel, const char *colName, @@ -3672,6 +3674,7 @@ AlterTableGetLockLevel(List *cmds) case AT_AddIdentity: case AT_DropIdentity: case AT_SetIdentity: + case AT_DropExpression: cmd_lockmode = AccessExclusiveLock; break; @@ -3946,6 +3949,12 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd, /* No command-specific prep needed */ pass = AT_PASS_COL_ATTRS; break; + case AT_DropExpression: /* ALTER COLUMN DROP EXPRESSION */ + ATSimplePermissions(rel, ATT_TABLE | ATT_FOREIGN_TABLE); + ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode); + ATPrepDropExpression(rel, cmd, recursing); + pass = AT_PASS_DROP; + break; case AT_SetStatistics: /* ALTER COLUMN SET STATISTICS */ ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW | ATT_INDEX | ATT_PARTITIONED_INDEX | ATT_FOREIGN_TABLE); ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode); @@ -4265,6 +4274,9 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel, case AT_CheckNotNull: /* check column is already marked NOT NULL */ ATExecCheckNotNull(tab, rel, cmd->name, lockmode); break; + case AT_DropExpression: + address = ATExecDropExpression(rel, cmd->name, cmd->missing_ok, lockmode); + break; case AT_SetStatistics: /* ALTER COLUMN SET STATISTICS */ address = ATExecSetStatistics(rel, cmd->name, cmd->num, cmd->def, lockmode); break; @@ -6457,7 +6469,9 @@ ATExecColumnDefault(Relation rel, const char *colName, ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("column \"%s\" of relation \"%s\" is a generated column", - colName, RelationGetRelationName(rel)))); + colName, RelationGetRelationName(rel)), + newDefault || TupleDescAttr(tupdesc, attnum - 1)->attgenerated != ATTRIBUTE_GENERATED_STORED ? 0 : + errhint("Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead."))); /* * Remove any old default for the column. We use RESTRICT here for @@ -6726,6 +6740,151 @@ ATExecDropIdentity(Relation rel, const char *colName, bool missing_ok, LOCKMODE } /* + * ALTER TABLE ALTER COLUMN DROP EXPRESSION + */ +static void +ATPrepDropExpression(Relation rel, AlterTableCmd *cmd, bool recursing) +{ + /* + * Cannot drop generation expression from inherited columns. + */ + if (!recursing) + { + HeapTuple tuple; + Form_pg_attribute attTup; + + tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), cmd->name); + if (!HeapTupleIsValid(tuple)) + ereport(ERROR, + (errcode(ERRCODE_UNDEFINED_COLUMN), + errmsg("column \"%s\" of relation \"%s\" does not exist", + cmd->name, RelationGetRelationName(rel)))); + + attTup = (Form_pg_attribute) GETSTRUCT(tuple); + + if (attTup->attinhcount > 0) + ereport(ERROR, + (errcode(ERRCODE_INVALID_TABLE_DEFINITION), + errmsg("cannot drop generation expression from inherited column"))); + } +} + +/* + * Return the address of the affected column. + */ +static ObjectAddress +ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMODE lockmode) +{ + HeapTuple tuple; + Form_pg_attribute attTup; + AttrNumber attnum; + Relation attrelation; + ObjectAddress address; + + attrelation = table_open(AttributeRelationId, RowExclusiveLock); + tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName); + if (!HeapTupleIsValid(tuple)) + ereport(ERROR, + (errcode(ERRCODE_UNDEFINED_COLUMN), + errmsg("column \"%s\" of relation \"%s\" does not exist", + colName, RelationGetRelationName(rel)))); + + attTup = (Form_pg_attribute) GETSTRUCT(tuple); + attnum = attTup->attnum; + + if (attnum <= 0) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot alter system column \"%s\"", + colName))); + + if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED) + { + if (!missing_ok) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("column \"%s\" of relation \"%s\" is not a stored generated column", + colName, RelationGetRelationName(rel)))); + else + { + ereport(NOTICE, + (errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping", + colName, RelationGetRelationName(rel)))); + heap_freetuple(tuple); + table_close(attrelation, RowExclusiveLock); + return InvalidObjectAddress; + } + } + + attTup->attgenerated = '\0'; + CatalogTupleUpdate(attrelation, &tuple->t_self, tuple); + + InvokeObjectPostAlterHook(RelationRelationId, + RelationGetRelid(rel), + attTup->attnum); + ObjectAddressSubSet(address, RelationRelationId, + RelationGetRelid(rel), attnum); + heap_freetuple(tuple); + + table_close(attrelation, RowExclusiveLock); + + CommandCounterIncrement(); + + RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, false, false); + + /* + * Remove all dependencies of this (formerly generated) column on other + * columns in the same table. (See StoreAttrDefault() for which + * dependencies are created.) We don't expect there to be dependencies + * between columns of the same table for other reasons, so it's okay to + * remove all of them. + */ + { + Relation depRel; + ScanKeyData key[3]; + SysScanDesc scan; + HeapTuple tup; + + depRel = table_open(DependRelationId, RowExclusiveLock); + + ScanKeyInit(&key[0], + Anum_pg_depend_classid, + BTEqualStrategyNumber, F_OIDEQ, + ObjectIdGetDatum(RelationRelationId)); + ScanKeyInit(&key[1], + Anum_pg_depend_objid, + BTEqualStrategyNumber, F_OIDEQ, + ObjectIdGetDatum(RelationGetRelid(rel))); + ScanKeyInit(&key[2], + Anum_pg_depend_objsubid, + BTEqualStrategyNumber, F_INT4EQ, + Int32GetDatum(attnum)); + + scan = systable_beginscan(depRel, DependDependerIndexId, true, + NULL, 3, key); + + while (HeapTupleIsValid(tup = systable_getnext(scan))) + { + Form_pg_depend depform = (Form_pg_depend) GETSTRUCT(tup); + + if (depform->refclassid == RelationRelationId && + depform->refobjid == RelationGetRelid(rel) && + depform->refobjsubid != 0 && + depform->deptype == DEPENDENCY_AUTO) + { + CatalogTupleDelete(depRel, &tup->t_self); + } + } + + systable_endscan(scan); + + table_close(depRel, RowExclusiveLock); + } + + return address; +} + +/* * ALTER TABLE ALTER COLUMN SET STATISTICS * * Return value is the address of the modified column |