diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index e7b23f1621cd3a901b3b8209ec1ea10ac0a00485..1c7eded9a79cddb7e24bd98f0deddee5a9089fcc 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -386,6 +386,8 @@ static void ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab,
static void ATPostAlterTypeParse(Oid oldId, Oid oldRelId, Oid refRelId,
char *cmd, List **wqueue, LOCKMODE lockmode,
bool rewrite);
+static void RebuildConstraintComment(AlteredTableInfo *tab, int pass,
+ Oid objid, Relation rel, char *conname);
static void TryReuseIndex(Oid oldId, IndexStmt *stmt);
static void TryReuseForeignKey(Oid oldId, Constraint *con);
static void change_owner_fix_column_acls(Oid relationOid,
@@ -3514,6 +3516,9 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
ATExecAddConstraint(wqueue, tab, rel, (Constraint *) cmd->def,
false, true, lockmode);
break;
+ case AT_ReAddComment: /* Re-add existing comment */
+ address = CommentObject((CommentStmt *) cmd->def);
+ break;
case AT_AddIndexConstraint: /* ADD CONSTRAINT USING INDEX */
address = ATExecAddIndexConstraint(tab, rel, (IndexStmt *) cmd->def,
lockmode);
@@ -8654,6 +8659,8 @@ ATPostAlterTypeParse(Oid oldId, Oid oldRelId, Oid refRelId, char *cmd,
if (!rewrite)
TryReuseIndex(oldId, stmt);
+ /* keep the index's comment */
+ stmt->idxcomment = GetComment(oldId, RelationRelationId, 0);
newcmd = makeNode(AlterTableCmd);
newcmd->subtype = AT_ReAddIndex;
@@ -8672,15 +8679,29 @@ ATPostAlterTypeParse(Oid oldId, Oid oldRelId, Oid refRelId, char *cmd,
if (cmd->subtype == AT_AddIndex)
{
+ IndexStmt *indstmt;
+ Oid indoid;
+
Assert(IsA(cmd->def, IndexStmt));
+ indstmt = (IndexStmt *) cmd->def;
+ indoid = get_constraint_index(oldId);
+
if (!rewrite)
- TryReuseIndex(get_constraint_index(oldId),
- (IndexStmt *) cmd->def);
+ TryReuseIndex(indoid, indstmt);
+ /* keep any comment on the index */
+ indstmt->idxcomment = GetComment(indoid,
+ RelationRelationId, 0);
cmd->subtype = AT_ReAddIndex;
tab->subcmds[AT_PASS_OLD_INDEX] =
lappend(tab->subcmds[AT_PASS_OLD_INDEX], cmd);
+
+ /* recreate any comment on the constraint */
+ RebuildConstraintComment(tab,
+ AT_PASS_OLD_INDEX,
+ oldId,
+ rel, indstmt->idxname);
}
else if (cmd->subtype == AT_AddConstraint)
{
@@ -8697,6 +8718,12 @@ ATPostAlterTypeParse(Oid oldId, Oid oldRelId, Oid refRelId, char *cmd,
cmd->subtype = AT_ReAddConstraint;
tab->subcmds[AT_PASS_OLD_CONSTR] =
lappend(tab->subcmds[AT_PASS_OLD_CONSTR], cmd);
+
+ /* recreate any comment on the constraint */
+ RebuildConstraintComment(tab,
+ AT_PASS_OLD_CONSTR,
+ oldId,
+ rel, con->conname);
}
else
elog(ERROR, "unexpected statement type: %d",
@@ -8711,6 +8738,40 @@ ATPostAlterTypeParse(Oid oldId, Oid oldRelId, Oid refRelId, char *cmd,
relation_close(rel, NoLock);
}
+/*
+ * Subroutine for ATPostAlterTypeParse() to recreate a comment entry for
+ * a constraint that is being re-added.
+ */
+static void
+RebuildConstraintComment(AlteredTableInfo *tab, int pass, Oid objid,
+ Relation rel, char *conname)
+{
+ CommentStmt *cmd;
+ char *comment_str;
+ AlterTableCmd *newcmd;
+
+ /* Look for comment for object wanted, and leave if none */
+ comment_str = GetComment(objid, ConstraintRelationId, 0);
+ if (comment_str == NULL)
+ return;
+
+ /* Build node CommentStmt */
+ cmd = makeNode(CommentStmt);
+ cmd->objtype = OBJECT_TABCONSTRAINT;
+ cmd->objname = list_make3(
+ makeString(get_namespace_name(RelationGetNamespace(rel))),
+ makeString(RelationGetRelationName(rel)),
+ makeString(conname));
+ cmd->objargs = NIL;
+ cmd->comment = comment_str;
+
+ /* Append it to list of commands */
+ newcmd = makeNode(AlterTableCmd);
+ newcmd->subtype = AT_ReAddComment;
+ newcmd->def = (Node *) cmd;
+ tab->subcmds[pass] = lappend(tab->subcmds[pass], newcmd);
+}
+
/*
* Subroutine for ATPostAlterTypeParse(). Calls out to CheckIndexCompatible()
* for the real analysis, then mutates the IndexStmt based on that verdict.
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 868905b0c16f6240ca38f8f20d90fdd14c192460..a567c50da7279c960b4c4ca503b1b81854427cc8 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1474,6 +1474,7 @@ typedef enum AlterTableType
AT_AddConstraint, /* add constraint */
AT_AddConstraintRecurse, /* internal to commands/tablecmds.c */
AT_ReAddConstraint, /* internal to commands/tablecmds.c */
+ AT_ReAddComment, /* internal to commands/tablecmds.c */
AT_AlterConstraint, /* alter constraint */
AT_ValidateConstraint, /* validate constraint */
AT_ValidateConstraintRecurse, /* internal to commands/tablecmds.c */
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 3ad2c55775c64e61e1f01f8929a04dfb95f5f1c3..6b9291b7242bcf9661739c4cb7fa506c14bbe307 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -2400,6 +2400,69 @@ Check constraints:
DROP TABLE alter2.tt8;
DROP SCHEMA alter2;
+-- Check that comments on constraints and indexes are not lost at ALTER TABLE.
+CREATE TABLE comment_test (
+ id int,
+ positive_col int CHECK (positive_col > 0),
+ indexed_col int,
+ CONSTRAINT comment_test_pk PRIMARY KEY (id));
+CREATE INDEX comment_test_index ON comment_test(indexed_col);
+COMMENT ON COLUMN comment_test.id IS 'Column ''id'' on comment_test';
+COMMENT ON INDEX comment_test_index IS 'Simple index on comment_test';
+COMMENT ON CONSTRAINT comment_test_positive_col_check ON comment_test IS 'CHECK constraint on comment_test.positive_col';
+COMMENT ON CONSTRAINT comment_test_pk ON comment_test IS 'PRIMARY KEY constraint of comment_test';
+COMMENT ON INDEX comment_test_pk IS 'Index backing the PRIMARY KEY of comment_test';
+SELECT col_description('comment_test'::regclass, 1) as comment;
+ comment
+-----------------------------
+ Column 'id' on comment_test
+(1 row)
+
+SELECT indexrelid::regclass as index, obj_description(indexrelid, 'pg_class') as comment FROM pg_index where indrelid = 'comment_test'::regclass;
+ index | comment
+--------------------+-----------------------------------------------
+ comment_test_index | Simple index on comment_test
+ comment_test_pk | Index backing the PRIMARY KEY of comment_test
+(2 rows)
+
+SELECT conname as constraint, obj_description(oid, 'pg_constraint') as comment FROM pg_constraint where conrelid = 'comment_test'::regclass;
+ constraint | comment
+---------------------------------+-----------------------------------------------
+ comment_test_pk | PRIMARY KEY constraint of comment_test
+ comment_test_positive_col_check | CHECK constraint on comment_test.positive_col
+(2 rows)
+
+-- Change the datatype of all the columns. ALTER TABLE is optimized to not
+-- rebuild an index if the new data type is binary compatible with the old
+-- one. Check do a dummy ALTER TABLE that doesn't change the datatype
+-- first, to test that no-op codepath, and another one that does.
+ALTER TABLE comment_test ALTER COLUMN indexed_col SET DATA TYPE int;
+ALTER TABLE comment_test ALTER COLUMN indexed_col SET DATA TYPE text;
+ALTER TABLE comment_test ALTER COLUMN id SET DATA TYPE int;
+ALTER TABLE comment_test ALTER COLUMN id SET DATA TYPE text;
+ALTER TABLE comment_test ALTER COLUMN positive_col SET DATA TYPE int;
+ALTER TABLE comment_test ALTER COLUMN positive_col SET DATA TYPE bigint;
+-- Check that the comments are intact.
+SELECT col_description('comment_test'::regclass, 1) as comment;
+ comment
+-----------------------------
+ Column 'id' on comment_test
+(1 row)
+
+SELECT indexrelid::regclass as index, obj_description(indexrelid, 'pg_class') as comment FROM pg_index where indrelid = 'comment_test'::regclass;
+ index | comment
+--------------------+-----------------------------------------------
+ comment_test_pk | Index backing the PRIMARY KEY of comment_test
+ comment_test_index | Simple index on comment_test
+(2 rows)
+
+SELECT conname as constraint, obj_description(oid, 'pg_constraint') as comment FROM pg_constraint where conrelid = 'comment_test'::regclass;
+ constraint | comment
+---------------------------------+-----------------------------------------------
+ comment_test_positive_col_check | CHECK constraint on comment_test.positive_col
+ comment_test_pk | PRIMARY KEY constraint of comment_test
+(2 rows)
+
-- Check that we map relation oids to filenodes and back correctly. Only
-- display bad mappings so the test output doesn't change all the time. A
-- filenode function call can return NULL for a relation dropped concurrently
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 29c1875d2eaec34c58be594aa18fc65330e25828..9f755fae33f73d891496e3a9fac4ccb7bf860124 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -1594,6 +1594,42 @@ ALTER TABLE IF EXISTS tt8 SET SCHEMA alter2;
DROP TABLE alter2.tt8;
DROP SCHEMA alter2;
+
+-- Check that comments on constraints and indexes are not lost at ALTER TABLE.
+CREATE TABLE comment_test (
+ id int,
+ positive_col int CHECK (positive_col > 0),
+ indexed_col int,
+ CONSTRAINT comment_test_pk PRIMARY KEY (id));
+CREATE INDEX comment_test_index ON comment_test(indexed_col);
+
+COMMENT ON COLUMN comment_test.id IS 'Column ''id'' on comment_test';
+COMMENT ON INDEX comment_test_index IS 'Simple index on comment_test';
+COMMENT ON CONSTRAINT comment_test_positive_col_check ON comment_test IS 'CHECK constraint on comment_test.positive_col';
+COMMENT ON CONSTRAINT comment_test_pk ON comment_test IS 'PRIMARY KEY constraint of comment_test';
+COMMENT ON INDEX comment_test_pk IS 'Index backing the PRIMARY KEY of comment_test';
+
+SELECT col_description('comment_test'::regclass, 1) as comment;
+SELECT indexrelid::regclass as index, obj_description(indexrelid, 'pg_class') as comment FROM pg_index where indrelid = 'comment_test'::regclass;
+SELECT conname as constraint, obj_description(oid, 'pg_constraint') as comment FROM pg_constraint where conrelid = 'comment_test'::regclass;
+
+-- Change the datatype of all the columns. ALTER TABLE is optimized to not
+-- rebuild an index if the new data type is binary compatible with the old
+-- one. Check do a dummy ALTER TABLE that doesn't change the datatype
+-- first, to test that no-op codepath, and another one that does.
+ALTER TABLE comment_test ALTER COLUMN indexed_col SET DATA TYPE int;
+ALTER TABLE comment_test ALTER COLUMN indexed_col SET DATA TYPE text;
+ALTER TABLE comment_test ALTER COLUMN id SET DATA TYPE int;
+ALTER TABLE comment_test ALTER COLUMN id SET DATA TYPE text;
+ALTER TABLE comment_test ALTER COLUMN positive_col SET DATA TYPE int;
+ALTER TABLE comment_test ALTER COLUMN positive_col SET DATA TYPE bigint;
+
+-- Check that the comments are intact.
+SELECT col_description('comment_test'::regclass, 1) as comment;
+SELECT indexrelid::regclass as index, obj_description(indexrelid, 'pg_class') as comment FROM pg_index where indrelid = 'comment_test'::regclass;
+SELECT conname as constraint, obj_description(oid, 'pg_constraint') as comment FROM pg_constraint where conrelid = 'comment_test'::regclass;
+
+
-- Check that we map relation oids to filenodes and back correctly. Only
-- display bad mappings so the test output doesn't change all the time. A
-- filenode function call can return NULL for a relation dropped concurrently