Fix segfault when setting chunk replica identity

The segfault happened executing `AlterTableInternal` for setting the
REPLICA IDENTITY during chunk creation (introduced by timescale#5512) that is
dispatched by a trigger invoked by a DDL statement.

Fixed it by using our internal `ts_alter_table_with_event_trigger`
handler function to setup the event trigger context.

Fixes timescale#7406

.unreleased/pr_7434

@@ -0,0 +1,2 @@
+Fixes: #7434 Fixes segfault when internally set the replica identity for a given chunk
+Thanks: @bharrisau for reporting the segfault when creating chunks

src/chunk.c

@@ -875,6 +875,16 @@ static void
 chunk_set_replica_identity(const Chunk *chunk)
 {
 	Relation ht_rel = relation_open(chunk->hypertable_relid, AccessShareLock);
+	Relation ch_rel = relation_open(chunk->table_id, AccessShareLock);
+
+	/* Do nothing if REPLICA IDENTITY of hypertable and chunk are equal */
+	if (ht_rel->rd_rel->relreplident == ch_rel->rd_rel->relreplident)
+	{
+		table_close(ch_rel, NoLock);
+		table_close(ht_rel, NoLock);
+		return;
+	}
+
 	ReplicaIdentityStmt stmt = {
 		.type = T_ReplicaIdentityStmt,
 		.identity_type = ht_rel->rd_rel->relreplident,
@@ -900,8 +910,9 @@ chunk_set_replica_identity(const Chunk *chunk)
 	}
 
 	ts_catalog_database_info_become_owner(ts_catalog_database_info_get(), &sec_ctx);
-	AlterTableInternal(chunk->table_id, list_make1(&cmd), false);
+	ts_alter_table_with_event_trigger(chunk->table_id, NULL, list_make1(&cmd), false);
 	ts_catalog_restore_user(&sec_ctx);
+	table_close(ch_rel, NoLock);
 	table_close(ht_rel, NoLock);
 }
 

test/expected/create_chunks.out

@@ -221,3 +221,74 @@ ERROR:  invalid interval: an explicit interval must be specified
 SELECT set_chunk_time_interval('chunk_test2', NULL::INTERVAL);
 ERROR:  invalid interval: an explicit interval must be specified
 \set ON_ERROR_STOP 1
+-- Issue https://github.com/timescale/timescaledb/issues/7406
+CREATE TABLE test_ht (time TIMESTAMPTZ, v1 INTEGER);
+SELECT create_hypertable('test_ht', by_range('time', INTERVAL '1 hour'));
+NOTICE:  adding not-null constraint to column "time"
+ create_hypertable 
+-------------------
+ (4,t)
+(1 row)
+
+CREATE TABLE test_tb (time TIMESTAMPTZ, v1 INTEGER);
+CREATE OR REPLACE FUNCTION test_tb_trg_insert() RETURNS TRIGGER AS $$
+BEGIN
+  INSERT INTO test_ht VALUES (NEW.time, NEW.v1);
+  RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+CREATE TRIGGER test_tb_trg_insert AFTER
+INSERT ON test_tb
+FOR EACH ROW EXECUTE FUNCTION test_tb_trg_insert();
+-- Creating new chunk inside a trigger called by
+-- a DDL statement should not fail.
+CREATE TABLE test_output AS
+WITH inserted AS (
+  INSERT INTO test_tb VALUES (NOW(), 1), (NOW(), 2) RETURNING *
+)
+SELECT * FROM inserted;
+-- Check the DEFAULT REPLICA IDENTITY of the chunks
+SELECT relname, relreplident FROM show_chunks('test_ht') ch JOIN pg_class c ON (ch = c.oid) ORDER BY relname;
+      relname      | relreplident 
+-------------------+--------------
+ _hyper_4_11_chunk | d
+(1 row)
+
+-- Clean up
+TRUNCATE test_ht, test_tb;
+DROP TABLE test_output;
+-- Change the DEFAULT REPLICA IDENTITY of the chunks
+ALTER TABLE test_ht REPLICA IDENTITY FULL;
+-- Internally we force new chunks have the same REPLICA IDENTITY
+-- as the parent table.
+CREATE TABLE test_output AS
+WITH inserted AS (
+  INSERT INTO test_tb VALUES (NOW(), 1), (NOW(), 2) RETURNING *
+)
+SELECT * FROM inserted;
+-- Check current new REPLICA IDENTITY FULL in the chunks
+SELECT relname, relreplident FROM show_chunks('test_ht') ch JOIN pg_class c ON (ch = c.oid) ORDER BY relname;
+      relname      | relreplident 
+-------------------+--------------
+ _hyper_4_12_chunk | f
+(1 row)
+
+-- All tables should have the same number of rows
+SELECT count(*) FROM test_tb;
+ count 
+-------
+     2
+(1 row)
+
+SELECT count(*) FROM test_ht;
+ count 
+-------
+     2
+(1 row)
+
+SELECT count(*) FROM test_output;
+ count 
+-------
+     2
+(1 row)
+

test/sql/create_chunks.sql

@@ -121,3 +121,53 @@ SELECT set_chunk_time_interval('chunk_test', NULL::BIGINT);
 SELECT set_chunk_time_interval('chunk_test2', NULL::BIGINT);
 SELECT set_chunk_time_interval('chunk_test2', NULL::INTERVAL);
 \set ON_ERROR_STOP 1
+
+-- Issue https://github.com/timescale/timescaledb/issues/7406
+CREATE TABLE test_ht (time TIMESTAMPTZ, v1 INTEGER);
+SELECT create_hypertable('test_ht', by_range('time', INTERVAL '1 hour'));
+CREATE TABLE test_tb (time TIMESTAMPTZ, v1 INTEGER);
+
+CREATE OR REPLACE FUNCTION test_tb_trg_insert() RETURNS TRIGGER AS $$
+BEGIN
+  INSERT INTO test_ht VALUES (NEW.time, NEW.v1);
+  RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER test_tb_trg_insert AFTER
+INSERT ON test_tb
+FOR EACH ROW EXECUTE FUNCTION test_tb_trg_insert();
+
+-- Creating new chunk inside a trigger called by
+-- a DDL statement should not fail.
+CREATE TABLE test_output AS
+WITH inserted AS (
+  INSERT INTO test_tb VALUES (NOW(), 1), (NOW(), 2) RETURNING *
+)
+SELECT * FROM inserted;
+
+-- Check the DEFAULT REPLICA IDENTITY of the chunks
+SELECT relname, relreplident FROM show_chunks('test_ht') ch JOIN pg_class c ON (ch = c.oid) ORDER BY relname;
+
+-- Clean up
+TRUNCATE test_ht, test_tb;
+DROP TABLE test_output;
+
+-- Change the DEFAULT REPLICA IDENTITY of the chunks
+ALTER TABLE test_ht REPLICA IDENTITY FULL;
+
+-- Internally we force new chunks have the same REPLICA IDENTITY
+-- as the parent table.
+CREATE TABLE test_output AS
+WITH inserted AS (
+  INSERT INTO test_tb VALUES (NOW(), 1), (NOW(), 2) RETURNING *
+)
+SELECT * FROM inserted;
+
+-- Check current new REPLICA IDENTITY FULL in the chunks
+SELECT relname, relreplident FROM show_chunks('test_ht') ch JOIN pg_class c ON (ch = c.oid) ORDER BY relname;
+
+-- All tables should have the same number of rows
+SELECT count(*) FROM test_tb;
+SELECT count(*) FROM test_ht;
+SELECT count(*) FROM test_output;