disable some of the concurrent data modification operations for partitioned tables

Author: funbringer

hash.sql

@@ -29,6 +29,11 @@ BEGIN
 	/* Acquire exclusive lock on parent */
 	PERFORM @extschema@.lock_partitioned_relation(parent_relid);
 
+	IF partition_data = true THEN
+		/* Acquire data modification lock */
+		PERFORM @extschema@.lock_relation_modification(parent_relid);
+	END IF;
+
 	PERFORM @extschema@.validate_relname(parent_relid);
 	attribute := lower(attribute);
 	PERFORM @extschema@.common_relation_checks(parent_relid, attribute);

init.sql

@@ -656,6 +656,14 @@ LANGUAGE C STRICT;
  LANGUAGE C STRICT;
 
 
+/*
+ * Lock relation to restrict concurrent modification of data.
+ */
+ CREATE OR REPLACE FUNCTION @extschema@.lock_relation_modification(
+	 REGCLASS)
+ RETURNS VOID AS 'pg_pathman', 'lock_relation_modification'
+ LANGUAGE C STRICT;
+
 /*
  * DEBUG: Place this inside some plpgsql fuction and set breakpoint.
  */

range.sql

@@ -97,6 +97,11 @@ BEGIN
 	/* Acquire exclusive lock on parent */
 	PERFORM @extschema@.lock_partitioned_relation(parent_relid);
 
+	IF partition_data = true THEN
+		/* Acquire data modification lock */
+		PERFORM @extschema@.lock_relation_modification(parent_relid);
+	END IF;
+
 	PERFORM @extschema@.validate_relname(parent_relid);
 	p_attribute := lower(p_attribute);
 	PERFORM @extschema@.common_relation_checks(parent_relid, p_attribute);
@@ -194,6 +199,11 @@ BEGIN
 	/* Acquire exclusive lock on parent */
 	PERFORM @extschema@.lock_partitioned_relation(parent_relid);
 
+	IF partition_data = true THEN
+		/* Acquire data modification lock */
+		PERFORM @extschema@.lock_relation_modification(parent_relid);
+	END IF;
+
 	PERFORM @extschema@.validate_relname(parent_relid);
 	p_attribute := lower(p_attribute);
 	PERFORM @extschema@.common_relation_checks(parent_relid, p_attribute);
@@ -289,6 +299,11 @@ BEGIN
 	/* Acquire exclusive lock on parent */
 	PERFORM @extschema@.lock_partitioned_relation(parent_relid);
 
+	IF partition_data = true THEN
+		/* Acquire data modification lock */
+		PERFORM @extschema@.lock_relation_modification(parent_relid);
+	END IF;
+
 	PERFORM @extschema@.validate_relname(parent_relid);
 	p_attribute := lower(p_attribute);
 	PERFORM @extschema@.common_relation_checks(parent_relid, p_attribute);
@@ -357,6 +372,11 @@ BEGIN
 	/* Acquire exclusive lock on parent */
 	PERFORM @extschema@.lock_partitioned_relation(parent_relid);
 
+	IF partition_data = true THEN
+		/* Acquire data modification lock */
+		PERFORM @extschema@.lock_relation_modification(parent_relid);
+	END IF;
+
 	PERFORM @extschema@.validate_relname(parent_relid);
 	p_attribute := lower(p_attribute);
 	PERFORM @extschema@.common_relation_checks(parent_relid, p_attribute);
@@ -501,6 +521,9 @@ BEGIN
 	/* Acquire exclusive lock on parent */
 	PERFORM @extschema@.lock_partitioned_relation(v_parent_relid);
 
+	/* Acquire data modification lock */
+	PERFORM @extschema@.lock_relation_modification(p_partition);
+
 	SELECT attname, parttype
 	FROM @extschema@.pathman_config
 	WHERE partrel = v_parent_relid
@@ -585,6 +608,10 @@ BEGIN
 	v_parent_relid1 := @extschema@.get_parent_of_partition(partition1);
 	v_parent_relid2 := @extschema@.get_parent_of_partition(partition2);
 
+	/* Acquire data modification lock */
+	PERFORM @extschema@.lock_relation_modification(partition1);
+	PERFORM @extschema@.lock_relation_modification(partition2);
+
 	IF v_parent_relid1 != v_parent_relid2 THEN
 		RAISE EXCEPTION 'Cannot merge partitions with different parents';
 	END IF;

src/pl_funcs.c

@@ -53,6 +53,7 @@ PG_FUNCTION_INFO_V1( is_attribute_nullable );
 PG_FUNCTION_INFO_V1( add_to_pathman_config );
 PG_FUNCTION_INFO_V1( invalidate_relcache );
 PG_FUNCTION_INFO_V1( lock_partitioned_relation );
+PG_FUNCTION_INFO_V1( lock_relation_modification );
 PG_FUNCTION_INFO_V1( debug_capture );
 
 
@@ -701,6 +702,17 @@ lock_partitioned_relation(PG_FUNCTION_ARGS)
 	PG_RETURN_VOID();
 }
 
+Datum
+lock_relation_modification(PG_FUNCTION_ARGS)
+{
+	Oid			relid = PG_GETARG_OID(0);
+
+	/* Lock partitioned relation till transaction's end */
+	xact_lock_rel_data(relid);
+
+	PG_RETURN_VOID();
+}
+
 
 /*
  * NOTE: used for DEBUG, set breakpoint here.

src/xact_handling.c

@@ -39,6 +39,24 @@ xact_unlock_partitioned_rel(Oid relid)
 	UnlockRelationOid(relid, ShareUpdateExclusiveLock);
 }
 
+/*
+ * Lock certain relation's data (INSERT | UPDATE | DELETE).
+ */
+void
+xact_lock_rel_data(Oid relid)
+{
+	LockRelationOid(relid, RowExclusiveLock);
+}
+
+/*
+ * Unlock relation's data.
+ */
+void
+xact_unlock_rel_data(Oid relid)
+{
+	UnlockRelationOid(relid, RowExclusiveLock);
+}
+
 /*
  * Check whether we already hold a lock that
  * might conflict with partition spawning BGW.

src/xact_handling.h

@@ -24,6 +24,10 @@ extern List	   *locked_by_me;
  */
 void xact_lock_partitioned_rel(Oid relid);
 void xact_unlock_partitioned_rel(Oid relid);
+
+void xact_lock_rel_data(Oid relid);
+void xact_unlock_rel_data(Oid relid);
+
 bool xact_conflicting_lock_exists(Oid relid);
 
 #endif