Use current user for repartition join temp schemas.

Otherwise when using a less privileged user we might get
errors when trying to create the schema.

src/backend/distributed/executor/repartition_join_execution.c

@@ -25,12 +25,15 @@
 
 #include "postgres.h"
 #include "access/hash.h"
+#include "miscadmin.h"
+#include "utils/builtins.h"
 #include "distributed/hash_helpers.h"
 
 #include "distributed/directed_acylic_graph_execution.h"
 #include "distributed/multi_physical_planner.h"
 #include "distributed/adaptive_executor.h"
 #include "distributed/worker_manager.h"
+#include "distributed/metadata_cache.h"
 #include "distributed/multi_server_executor.h"
 #include "distributed/repartition_join_execution.h"
 #include "distributed/worker_transaction.h"
@@ -46,7 +49,7 @@
 static List * CreateTemporarySchemasForMergeTasks(Job *topLevelJob);
 static List * ExtractJobsInJobTree(Job *job);
 static void TraverseJobTree(Job *curJob, List **jobs);
-static char * GenerateCreateSchemasCommand(List *jobIds);
+static char * GenerateCreateSchemasCommand(List *jobIds, char *schemaOwner);
 static char * GenerateJobCommands(List *jobIds, char *templateCommand);
 static char * GenerateDeleteJobsCommand(List *jobIds);
 
@@ -79,7 +82,7 @@ static List *
 CreateTemporarySchemasForMergeTasks(Job *topLeveLJob)
 {
 	List *jobIds = ExtractJobsInJobTree(topLeveLJob);
-	char *createSchemasCommand = GenerateCreateSchemasCommand(jobIds);
+	char *createSchemasCommand = GenerateCreateSchemasCommand(jobIds, CurrentUserName());
 	SendCommandToAllWorkers(createSchemasCommand, CitusExtensionOwnerName());
 	return jobIds;
 }
@@ -120,9 +123,18 @@ TraverseJobTree(Job *curJob, List **jobIds)
  * GenerateCreateSchemasCommand returns concatanated create schema commands.
  */
 static char *
-GenerateCreateSchemasCommand(List *jobIds)
+GenerateCreateSchemasCommand(List *jobIds, char *ownerName)
 {
-	return GenerateJobCommands(jobIds, WORKER_CREATE_SCHEMA_QUERY);
+	StringInfo createSchemaCommand = makeStringInfo();
+	ListCell *jobIdCell = NULL;
+
+	foreach(jobIdCell, jobIds)
+	{
+		uint64 jobId = (uint64) lfirst(jobIdCell);
+		appendStringInfo(createSchemaCommand, WORKER_CREATE_SCHEMA_QUERY,
+						 jobId, quote_literal_cstr(ownerName));
+	}
+	return createSchemaCommand->data;
 }
 
 

src/backend/distributed/sql/citus--9.2-1--9.2-2.sql

@@ -1,2 +1,4 @@
+#include "udfs/worker_create_schema/9.2-2.sql"
+
 -- reserve UINT32_MAX (4294967295) for a special node
 ALTER SEQUENCE pg_catalog.pg_dist_node_nodeid_seq MAXVALUE 4294967294;

src/backend/distributed/sql/udfs/worker_create_schema/9.2-2.sql

@@ -0,0 +1,10 @@
+DROP FUNCTION IF EXISTS pg_catalog.worker_create_schema(jobid bigint);
+
+CREATE FUNCTION pg_catalog.worker_create_schema(jobid bigint, username text)
+    RETURNS void
+    LANGUAGE C STRICT
+    AS 'MODULE_PATHNAME', $$worker_create_schema$$;
+COMMENT ON FUNCTION pg_catalog.worker_create_schema(bigint, text)
+    IS 'create schema in remote node';
+
+REVOKE ALL ON FUNCTION pg_catalog.worker_create_schema(bigint, text) FROM PUBLIC;

src/backend/distributed/sql/udfs/worker_create_schema/latest.sql

@@ -1,8 +1,10 @@
-CREATE FUNCTION pg_catalog.worker_create_schema(bigint)
+DROP FUNCTION IF EXISTS pg_catalog.worker_create_schema(jobid bigint);
+
+CREATE FUNCTION pg_catalog.worker_create_schema(jobid bigint, username text)
     RETURNS void
     LANGUAGE C STRICT
     AS 'MODULE_PATHNAME', $$worker_create_schema$$;
-COMMENT ON FUNCTION pg_catalog.worker_create_schema(bigint)
+COMMENT ON FUNCTION pg_catalog.worker_create_schema(bigint, text)
     IS 'create schema in remote node';
 
-REVOKE ALL ON FUNCTION pg_catalog.worker_create_schema(bigint) FROM PUBLIC;
+REVOKE ALL ON FUNCTION pg_catalog.worker_create_schema(bigint, text) FROM PUBLIC;

src/backend/distributed/worker/task_tracker_protocol.c

@@ -102,7 +102,7 @@ task_tracker_assign_task(PG_FUNCTION_ARGS)
 	if (!schemaExists)
 	{
 		/* lock gets automatically released upon return from this function */
-		CreateJobSchema(jobSchemaName);
+		CreateJobSchema(jobSchemaName, NULL);
 	}
 	else
 	{
@@ -306,9 +306,11 @@ TaskTrackerRunning(void)
  * this function ensures that our pg_ prefixed schema names can be created.
  * Further note that the created schema does not become visible to other
  * processes until the transaction commits.
+ *
+ * If schemaOwner is NULL, then current user is used.
  */
 void
-CreateJobSchema(StringInfo schemaName)
+CreateJobSchema(StringInfo schemaName, char *schemaOwner)
 {
 	const char *queryString = NULL;
 
@@ -324,10 +326,15 @@ CreateJobSchema(StringInfo schemaName)
 	GetUserIdAndSecContext(&savedUserId, &savedSecurityContext);
 	SetUserIdAndSecContext(CitusExtensionOwner(), SECURITY_LOCAL_USERID_CHANGE);
 
+	if (schemaOwner == NULL)
+	{
+		schemaOwner = GetUserNameFromId(savedUserId, false);
+	}
+
 	/* build a CREATE SCHEMA statement */
 	currentUserRole.type = T_RoleSpec;
 	currentUserRole.roletype = ROLESPEC_CSTRING;
-	currentUserRole.rolename = GetUserNameFromId(savedUserId, false);
+	currentUserRole.rolename = schemaOwner;
 	currentUserRole.location = -1;
 
 	CreateSchemaStmt *createSchemaStmt = makeNode(CreateSchemaStmt);

src/backend/distributed/worker/worker_merge_protocol.c

@@ -68,6 +68,9 @@ Datum
 worker_create_schema(PG_FUNCTION_ARGS)
 {
 	uint64 jobId = PG_GETARG_INT64(0);
+	text *ownerText = PG_GETARG_TEXT_P(1);
+	char *ownerString = TextDatumGetCString(ownerText);
+
 
 	StringInfo jobSchemaName = JobSchemaName(jobId);
 	CheckCitusVersion(ERROR);
@@ -75,7 +78,7 @@ worker_create_schema(PG_FUNCTION_ARGS)
 	bool schemaExists = JobSchemaExists(jobSchemaName);
 	if (!schemaExists)
 	{
-		CreateJobSchema(jobSchemaName);
+		CreateJobSchema(jobSchemaName, ownerString);
 	}
 
 	PG_RETURN_VOID();

src/include/distributed/multi_server_executor.h

@@ -37,7 +37,7 @@
 #define JOB_CLEANUP_TASK_ID INT_MAX
 
 /* Adaptive executor repartioning related defines */
-#define WORKER_CREATE_SCHEMA_QUERY "SELECT worker_create_schema (" UINT64_FORMAT ");"
+#define WORKER_CREATE_SCHEMA_QUERY "SELECT worker_create_schema (" UINT64_FORMAT ", %s);"
 #define WORKER_REPARTITION_CLEANUP_QUERY "SELECT worker_repartition_cleanup (" \
 	UINT64_FORMAT \
 	");"

src/include/distributed/task_tracker_protocol.h

@@ -17,7 +17,7 @@
 
 #include "fmgr.h"
 
-extern void CreateJobSchema(StringInfo schemaName);
+extern void CreateJobSchema(StringInfo schemaName, char *schemaOwner);
 
 /* Function declarations for distributed task management */
 extern Datum task_tracker_assign_task(PG_FUNCTION_ARGS);

src/test/regress/expected/multi_multiuser.out

@@ -155,6 +155,14 @@ SELECT count(*) FROM test a JOIN test b ON (a.val = b.val) WHERE a.id = 1 AND b.
      0
 (1 row)
 
+SET citus.task_executor_type TO 'adaptive';
+SET citus.enable_repartition_joins TO true;
+SELECT count(*) FROM test a JOIN test b ON (a.val = b.val) WHERE a.id = 1 AND b.id = 2;
+ count
+---------------------------------------------------------------------
+     0
+(1 row)
+
 -- should not be able to transmit directly
 COPY "postgresql.conf" TO STDOUT WITH (format transmit);
 ERROR:  operation is not allowed
@@ -235,6 +243,14 @@ SELECT count(*) FROM test a JOIN test b ON (a.val = b.val) WHERE a.id = 1 AND b.
      0
 (1 row)
 
+SET citus.task_executor_type TO 'adaptive';
+SET citus.enable_repartition_joins TO true;
+SELECT count(*) FROM test a JOIN test b ON (a.val = b.val) WHERE a.id = 1 AND b.id = 2;
+ count
+---------------------------------------------------------------------
+     0
+(1 row)
+
 -- should not be able to transmit directly
 COPY "postgresql.conf" TO STDOUT WITH (format transmit);
 ERROR:  operation is not allowed
@@ -277,6 +293,10 @@ ERROR:  permission denied for table test
 -- test re-partition query
 SELECT count(*) FROM test a JOIN test b ON (a.val = b.val) WHERE a.id = 1 AND b.id = 2;
 ERROR:  permission denied for table test
+SET citus.task_executor_type TO 'adaptive';
+SET citus.enable_repartition_joins TO true;
+SELECT count(*) FROM test a JOIN test b ON (a.val = b.val) WHERE a.id = 1 AND b.id = 2;
+ERROR:  permission denied for table test
 -- should not be able to transmit directly
 COPY "postgresql.conf" TO STDOUT WITH (format transmit);
 ERROR:  operation is not allowed

src/test/regress/sql/multi_multiuser.sql

@@ -112,6 +112,10 @@ SELECT count(*), min(current_user) FROM test;
 -- test re-partition query (needs to transmit intermediate results)
 SELECT count(*) FROM test a JOIN test b ON (a.val = b.val) WHERE a.id = 1 AND b.id = 2;
 
+SET citus.task_executor_type TO 'adaptive';
+SET citus.enable_repartition_joins TO true;
+SELECT count(*) FROM test a JOIN test b ON (a.val = b.val) WHERE a.id = 1 AND b.id = 2;
+
 -- should not be able to transmit directly
 COPY "postgresql.conf" TO STDOUT WITH (format transmit);
 
@@ -144,6 +148,10 @@ SELECT count(*), min(current_user) FROM test;
 -- test re-partition query (needs to transmit intermediate results)
 SELECT count(*) FROM test a JOIN test b ON (a.val = b.val) WHERE a.id = 1 AND b.id = 2;
 
+SET citus.task_executor_type TO 'adaptive';
+SET citus.enable_repartition_joins TO true;
+SELECT count(*) FROM test a JOIN test b ON (a.val = b.val) WHERE a.id = 1 AND b.id = 2;
+
 -- should not be able to transmit directly
 COPY "postgresql.conf" TO STDOUT WITH (format transmit);
 
@@ -176,6 +184,10 @@ SELECT count(*), min(current_user) FROM test;
 -- test re-partition query
 SELECT count(*) FROM test a JOIN test b ON (a.val = b.val) WHERE a.id = 1 AND b.id = 2;
 
+SET citus.task_executor_type TO 'adaptive';
+SET citus.enable_repartition_joins TO true;
+SELECT count(*) FROM test a JOIN test b ON (a.val = b.val) WHERE a.id = 1 AND b.id = 2;
+
 -- should not be able to transmit directly
 COPY "postgresql.conf" TO STDOUT WITH (format transmit);