From 5ed6546cf75623ba426942a3b71659a66cf7ed68 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 5 Nov 2012 13:36:16 -0500 Subject: [PATCH] Fix handling of inherited check constraints in ALTER COLUMN TYPE. This case got broken in 8.4 by the addition of an error check that complains if ALTER TABLE ONLY is used on a table that has children. We do use ONLY for this situation, but it's okay because the necessary recursion occurs at a higher level. So we need to have a separate flag to suppress recursion without making the error check. Reported and patched by Pavan Deolasee, with some editorial adjustments by me. Back-patch to 8.4, since this is a regression of functionality that worked in earlier branches. --- src/backend/commands/tablecmds.c | 43 +++++++++++++++++------ src/include/nodes/parsenodes.h | 1 + src/test/regress/expected/alter_table.out | 22 ++++++++++++ src/test/regress/sql/alter_table.sql | 7 ++++ 4 files changed, 63 insertions(+), 10 deletions(-) diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index 1bd9bef3e7..f88bf793e5 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -335,13 +335,15 @@ static void ATExecAddIndex(AlteredTableInfo *tab, Relation rel, IndexStmt *stmt, bool is_rebuild, LOCKMODE lockmode); static void ATExecAddConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel, - Constraint *newConstraint, bool recurse, LOCKMODE lockmode); + Constraint *newConstraint, bool recurse, bool is_readd, + LOCKMODE lockmode); static void ATExecAddIndexConstraint(AlteredTableInfo *tab, Relation rel, IndexStmt *stmt, LOCKMODE lockmode); static void ATAddCheckConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel, Constraint *constr, - bool recurse, bool recursing, LOCKMODE lockmode); + bool recurse, bool recursing, bool is_readd, + LOCKMODE lockmode); static void ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel, Constraint *fkconstraint, LOCKMODE lockmode); static void ATExecDropConstraint(Relation rel, const char *constrName, @@ -2758,6 +2760,7 @@ AlterTableGetLockLevel(List *cmds) case AT_ColumnDefault: case AT_ProcessedConstraint: /* becomes AT_AddConstraint */ case AT_AddConstraintRecurse: /* becomes AT_AddConstraint */ + case AT_ReAddConstraint: /* becomes AT_AddConstraint */ case AT_EnableTrig: case AT_EnableAlwaysTrig: case AT_EnableReplicaTrig: @@ -3249,11 +3252,15 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel, break; case AT_AddConstraint: /* ADD CONSTRAINT */ ATExecAddConstraint(wqueue, tab, rel, (Constraint *) cmd->def, - false, lockmode); + false, false, lockmode); break; case AT_AddConstraintRecurse: /* ADD CONSTRAINT with recursion */ ATExecAddConstraint(wqueue, tab, rel, (Constraint *) cmd->def, - true, lockmode); + true, false, lockmode); + break; + case AT_ReAddConstraint: /* Re-add pre-existing check constraint */ + ATExecAddConstraint(wqueue, tab, rel, (Constraint *) cmd->def, + false, true, lockmode); break; case AT_AddIndexConstraint: /* ADD CONSTRAINT USING INDEX */ ATExecAddIndexConstraint(tab, rel, (IndexStmt *) cmd->def, lockmode); @@ -5500,7 +5507,8 @@ ATExecAddIndexConstraint(AlteredTableInfo *tab, Relation rel, */ static void ATExecAddConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel, - Constraint *newConstraint, bool recurse, LOCKMODE lockmode) + Constraint *newConstraint, bool recurse, bool is_readd, + LOCKMODE lockmode) { Assert(IsA(newConstraint, Constraint)); @@ -5513,7 +5521,8 @@ ATExecAddConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel, { case CONSTR_CHECK: ATAddCheckConstraint(wqueue, tab, rel, - newConstraint, recurse, false, lockmode); + newConstraint, recurse, false, is_readd, + lockmode); break; case CONSTR_FOREIGN: @@ -5565,11 +5574,18 @@ ATExecAddConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel, * AddRelationNewConstraints would normally assign different names to the * child constraints. To fix that, we must capture the name assigned at * the parent table and pass that down. + * + * When re-adding a previously existing constraint (during ALTER COLUMN TYPE), + * we don't need to recurse here, because recursion will be carried out at a + * higher level; the constraint name issue doesn't apply because the names + * have already been assigned and are just being re-used. We need a separate + * "is_readd" flag for that; just setting recurse=false would result in an + * error if there are child tables. */ static void ATAddCheckConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel, Constraint *constr, bool recurse, bool recursing, - LOCKMODE lockmode) + bool is_readd, LOCKMODE lockmode) { List *newcons; ListCell *lcon; @@ -5634,9 +5650,11 @@ ATAddCheckConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel, return; /* - * Adding a NO INHERIT constraint? No need to find our children + * If adding a NO INHERIT constraint, no need to find our children. + * Likewise, in a re-add operation, we don't need to recurse (that will be + * handled at higher levels). */ - if (constr->is_no_inherit) + if (constr->is_no_inherit || is_readd) return; /* @@ -5671,7 +5689,7 @@ ATAddCheckConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel, /* Recurse to child */ ATAddCheckConstraint(wqueue, childtab, childrel, - constr, recurse, true, lockmode); + constr, recurse, true, is_readd, lockmode); heap_close(childrel, NoLock); } @@ -7862,6 +7880,10 @@ ATPostAlterTypeParse(Oid oldId, char *cmd, /* * Attach each generated command to the proper place in the work queue. * Note this could result in creation of entirely new work-queue entries. + * + * Also note that we have to tweak the command subtypes, because it turns + * out that re-creation of indexes and constraints has to act a bit + * differently from initial creation. */ foreach(list_item, querytree_list) { @@ -7919,6 +7941,7 @@ ATPostAlterTypeParse(Oid oldId, char *cmd, if (con->contype == CONSTR_FOREIGN && !rewrite && !tab->rewrite) TryReuseForeignKey(oldId, con); + cmd->subtype = AT_ReAddConstraint; tab->subcmds[AT_PASS_OLD_CONSTR] = lappend(tab->subcmds[AT_PASS_OLD_CONSTR], cmd); break; diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h index 09b15e7694..88344990f4 100644 --- a/src/include/nodes/parsenodes.h +++ b/src/include/nodes/parsenodes.h @@ -1197,6 +1197,7 @@ typedef enum AlterTableType AT_ReAddIndex, /* internal to commands/tablecmds.c */ AT_AddConstraint, /* add constraint */ AT_AddConstraintRecurse, /* internal to commands/tablecmds.c */ + AT_ReAddConstraint, /* internal to commands/tablecmds.c */ AT_ValidateConstraint, /* validate constraint */ AT_ValidateConstraintRecurse, /* internal to commands/tablecmds.c */ AT_ProcessedConstraint, /* pre-processed add constraint (local in diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out index c22d74c7b5..8392c27b36 100644 --- a/src/test/regress/expected/alter_table.out +++ b/src/test/regress/expected/alter_table.out @@ -1780,6 +1780,28 @@ where oid = 'test_storage'::regclass; t (1 row) +-- ALTER TYPE with a check constraint and a child table (bug before Nov 2012) +CREATE TABLE test_inh_check (a float check (a > 10.2)); +CREATE TABLE test_inh_check_child() INHERITS(test_inh_check); +ALTER TABLE test_inh_check ALTER COLUMN a TYPE numeric; +\d test_inh_check +Table "public.test_inh_check" + Column | Type | Modifiers +--------+---------+----------- + a | numeric | +Check constraints: + "test_inh_check_a_check" CHECK (a::double precision > 10.2::double precision) +Number of child tables: 1 (Use \d+ to list them.) + +\d test_inh_check_child +Table "public.test_inh_check_child" + Column | Type | Modifiers +--------+---------+----------- + a | numeric | +Check constraints: + "test_inh_check_a_check" CHECK (a::double precision > 10.2::double precision) +Inherits: test_inh_check + -- -- lock levels -- diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql index 0f9cb380e1..dcf8121d70 100644 --- a/src/test/regress/sql/alter_table.sql +++ b/src/test/regress/sql/alter_table.sql @@ -1239,6 +1239,13 @@ select reltoastrelid <> 0 as has_toast_table from pg_class where oid = 'test_storage'::regclass; +-- ALTER TYPE with a check constraint and a child table (bug before Nov 2012) +CREATE TABLE test_inh_check (a float check (a > 10.2)); +CREATE TABLE test_inh_check_child() INHERITS(test_inh_check); +ALTER TABLE test_inh_check ALTER COLUMN a TYPE numeric; +\d test_inh_check +\d test_inh_check_child + -- -- lock levels --