citus/src/backend/distributed/commands/aggregate.c

108 lines
3.3 KiB
C

/*-------------------------------------------------------------------------
*
* aggregate.c
* Commands for distributing AGGREGATE statements.
*
* Copyright (c) Citus Data, Inc.
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "distributed/commands.h"
#include "distributed/commands/utility_hook.h"
#include "distributed/deparser.h"
#include "distributed/listutils.h"
#include "distributed/metadata/dependency.h"
#include "distributed/metadata_sync.h"
#include "distributed/metadata/distobject.h"
#include "distributed/multi_executor.h"
#include "nodes/parsenodes.h"
#include "utils/lsyscache.h"
/*
* PostprocessDefineAggregateStmt actually creates the plan we need to execute for
* aggregate propagation.
* This is the downside of using the locally created aggregate to get the sql statement.
*
* If the aggregate depends on any non-distributed relation, Citus can not distribute it.
* In order to not to prevent users from creating local aggregates on the coordinator,
* a WARNING message will be sent to the user about the case instead of erroring out.
*
* Besides creating the plan we also make sure all (new) dependencies of the aggregate
* are created on all nodes.
*/
List *
PostprocessDefineAggregateStmt(Node *node, const char *queryString)
{
QualifyTreeNode((Node *) node);
DefineStmt *stmt = castNode(DefineStmt, node);
if (!ShouldPropagate())
{
return NIL;
}
if (!ShouldPropagateCreateInCoordinatedTransction())
{
return NIL;
}
ObjectAddress address = GetObjectAddressFromParseTree((Node *) stmt, false);
EnsureCoordinator();
EnsureSequentialMode(OBJECT_AGGREGATE);
ObjectAddress *undistributableDependency = GetUndistributableDependency(
&address);
if (undistributableDependency != NULL)
{
if (SupportedDependencyByCitus(undistributableDependency))
{
/*
* Citus can't distribute some relations as dependency, although those
* types as supported by Citus. So we can use get_rel_name directly
*/
RangeVar *aggRangeVar = makeRangeVarFromNameList(stmt->defnames);
char *aggName = aggRangeVar->relname;
char *dependentRelationName =
get_rel_name(undistributableDependency->objectId);
ereport(WARNING, (errmsg("Citus can't distribute aggregate \"%s\" having "
"dependency on non-distributed relation \"%s\"",
aggName, dependentRelationName),
errdetail("Aggregate will be created only locally"),
errhint("To distribute aggregate, distribute dependent "
"relations first. Then, re-create the aggregate")));
}
else
{
char *objectType = NULL;
#if PG_VERSION_NUM >= PG_VERSION_14
objectType = getObjectTypeDescription(undistributableDependency, false);
#else
objectType = getObjectTypeDescription(undistributableDependency);
#endif
ereport(WARNING, (errmsg("Citus can't distribute functions having "
"dependency on unsupported object of type \"%s\"",
objectType),
errdetail("Aggregate will be created only locally")));
}
return NIL;
}
EnsureDependenciesExistOnAllNodes(&address);
List *commands = CreateFunctionDDLCommandsIdempotent(&address);
commands = lcons(DISABLE_DDL_PROPAGATION, commands);
commands = lappend(commands, ENABLE_DDL_PROPAGATION);
return NodeDDLTaskList(NON_COORDINATOR_NODES, commands);
}