src/backend/catalog/toasting.c - hawq - Git at Google

 /*-------------------------------------------------------------------------
  *
  * toasting.c
  *	  This file contains routines to support creation of toast tables
  *
  *
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
  *	  $PostgreSQL: pgsql/src/backend/catalog/toasting.c,v 1.3 2006/10/04 00:29:50 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"

 #include "access/heapam.h"
 #include "access/tuptoaster.h"
 #include "access/xact.h"
 #include "catalog/catquery.h"
 #include "catalog/dependency.h"
 #include "catalog/heap.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
 #include "catalog/pg_namespace.h"
 #include "catalog/pg_opclass.h"
 #include "catalog/pg_type.h"
 #include "catalog/toasting.h"
 #include "commands/tablecmds.h"
 #include "commands/tablespace.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "utils/builtins.h"
 #include "utils/syscache.h"
 #include "utils/guc.h"

 #include "cdb/cdbvars.h"

 static bool create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 							   Oid *comptypeOid, bool is_part_child);


 /*
  * AlterTableCreateToastTable
  *		If the table needs a toast table, and doesn't already have one,
  *		then create a toast table for it.
  *
  * We expect the caller to have verified that the relation is a table and have
  * already done any necessary permission checks.  Callers expect this function
  * to end with CommandCounterIncrement if it makes any changes.
  */
 void
 AlterTableCreateToastTable(Oid relOid)
 {
 	Relation	rel;
 	bool is_part_child = !rel_needs_long_lock(relOid);

 	/*
 	 * Grab an exclusive lock on the target table, which we will NOT release
 	 * until end of transaction.  (This is probably redundant in all present
 	 * uses...)
 	 */
 	rel = heap_open(relOid, AccessExclusiveLock);

 	/* create_toast_table does all the work */
 	(void) create_toast_table(rel, InvalidOid, InvalidOid, NULL, is_part_child);

 	heap_close(rel, NoLock);
 }

 void
 AlterTableCreateToastTableWithOid(Oid relOid, Oid newOid, Oid newIndexOid,
 								  Oid * comptypeOid, bool is_part_child)
 {
 	Relation	rel;

 	/*
 	 * Grab an exclusive lock on the target table, which we will NOT release
 	 * until end of transaction.  (This is probably redundant in all present
 	 * uses...)
 	 */
 	if (is_part_child)
 		rel = heap_open(relOid, NoLock);
 	else
 		rel = heap_open(relOid, AccessExclusiveLock);


 	/* create_toast_table does all the work */
 	(void) create_toast_table(rel, newOid, newIndexOid,
 							  comptypeOid, is_part_child);

 	heap_close(rel, NoLock);
 }


 /*
  * Create a toast table during bootstrap
  *
  * Here we need to prespecify the OIDs of the toast table and its index
  */
 void
 BootstrapToastTable(char *relName, Oid toastOid, Oid toastIndexOid)
 {
 	Relation	rel;
 	Oid         typid;

 	rel = heap_openrv(makeRangeVar(NULL /*catalogname*/, NULL, relName, -1), AccessExclusiveLock);

 	/* Note: during bootstrap may see uncataloged relation */
 	if (rel->rd_rel->relkind != RELKIND_RELATION &&
 		rel->rd_rel->relkind != RELKIND_UNCATALOGED)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("\"%s\" is not a table",
 						relName)));

 	/*
 	 * In order to be able to support upgrade we need to be able to
 	 * support toast tables with fixed oids.  Toast tables created
 	 * pre 4.0 can continue to be dynamic, but anything new must
 	 * be declared in pg_type.h and again here.
 	 */
 	switch (toastOid)
 	{
 		/* New Toast Tables in 4.0 */

 /* TIDYCAT_BEGIN_CODEGEN
 */
 /*
    WARNING: DO NOT MODIFY THE FOLLOWING SECTION:
    Generated by ./tidycat.pl version 31
    on Thu Sep  1 16:43:17 2011
  */
 /* relation id: 5033 - pg_filespace_entry 20101122 */
 		case PgFileSpaceEntryToastTable:
 			typid = PG_FILESPACE_ENTRY_TOAST_RELTYPE_OID;
 			break;
 /* relation id: 5036 - gp_segment_configuration 20101122 */
 		case GpSegmentConfigToastTable:
 			typid = GP_SEGMENT_CONFIGURATION_TOAST_RELTYPE_OID;
 			break;
 /* relation id: 3231 - pg_attribute_encoding 20110727 */
 		case PgAttributeEncodingToastTable:
 			typid = PG_ATTRIBUTE_ENCODING_TOAST_RELTYPE_OID;
 			break;
 /* relation id: 3220 - pg_type_encoding 20110727 */
 		case PgTypeEncodingToastTable:
 			typid = PG_TYPE_ENCODING_TOAST_RELTYPE_OID;
 			break;
 /* relation id: 9903 - pg_partition_encoding 20110814 */
 		case PgPartitionEncodingToastTable:
 			typid = PG_PARTITION_ENCODING_TOAST_RELTYPE_OID;
 			break;
 /* relation id: 5080 - pg_filesystem 20120903 */
 		case PgFileSystemToastTable:
 			typid = PG_FILESYSTEM_TOAST_RELTYPE_OID;
 			break;

 /* relation id: 7076 - pg_remote_credentials 20140205 */
 		case PgRemoteCredentialsToastTable:
 			typid = PG_REMOTE_CREDENTIALS_TOAST_RELTYPE_OID;
 			break;

 /* relation id: 6026 - pg_resqueue 20140917 */
 		case PgResQueueToastTable:
 			typid = PG_RESQUEUE_TOAST_RELTYPE_OID;
 			break;

 /* TIDYCAT_END_CODEGEN */

 		default:
 			typid = InvalidOid;
 			break;
 	}

 	/* create_toast_table does all the work */
 	if (!create_toast_table(rel, toastOid, toastIndexOid, &typid, false))
 		elog(ERROR, "\"%s\" does not require a toast table",
 			 relName);

 	heap_close(rel, NoLock);
 }


 /*
  * create_toast_table --- internal workhorse
  *
  * rel is already opened and exclusive-locked
  * toastOid and toastIndexOid are normally InvalidOid, but during
  * bootstrap they can be nonzero to specify hand-assigned OIDs
  */
 static bool
 create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 				   Oid *comptypeOid, bool is_part_child)
 {
 	Oid			relOid = RelationGetRelid(rel);
 	HeapTuple	reltup;
 	TupleDesc	tupdesc;
 	bool		shared_relation;
 	Relation	class_rel;
 	Oid			toast_relid;
 	Oid			toast_idxid;
 	char		toast_relname[NAMEDATALEN];
 	char		toast_idxname[NAMEDATALEN];
 	IndexInfo  *indexInfo;
 	Oid			classObjectId[2];
 	ObjectAddress baseobject,
 				toastobject;
 	cqContext	cqc;
 	cqContext  *pcqCtx;
 	Oid			tablespaceOid = ChooseTablespaceForLimitedObject(rel->rd_rel->reltablespace);

 	/*
 	 * Is it already toasted?
 	 */
 	if (!gp_upgrade_mode && rel->rd_rel->reltoastrelid != InvalidOid)
 		return false;

 	/*
 	 * Check to see whether the table actually needs a TOAST table.
 	 */
 	if (!RelationNeedsToastTable(rel))
 		return false;

 	/*
 	 * If we're in upgrade mode, and we say we don't want a toast table
 	 * (by having an InvalidOid for toast Oid).
 	 */
 	if (gp_upgrade_mode && toastOid==InvalidOid)
 		return false;

 	/*
 	 * Toast table is shared if and only if its parent is.
 	 *
 	 * We cannot allow toasting a shared relation after initdb (because
 	 * there's no way to mark it toasted in other databases' pg_class).
 	 */
 	shared_relation = rel->rd_rel->relisshared;
 	if (shared_relation && !IsBootstrapProcessingMode()&&!gp_upgrade_mode)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("shared tables cannot be toasted after initdb")));

 	/*
 	 * Create the toast table and its index
 	 */
 	snprintf(toast_relname, sizeof(toast_relname),
 			 "pg_toast_%u", relOid);
 	snprintf(toast_idxname, sizeof(toast_idxname),
 			 "pg_toast_%u_index", relOid);

 	/* this is pretty painful...  need a tuple descriptor */
 	tupdesc = CreateTemplateTupleDesc(3, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1,
 					   "chunk_id",
 					   OIDOID,
 					   -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2,
 					   "chunk_seq",
 					   INT4OID,
 					   -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 3,
 					   "chunk_data",
 					   BYTEAOID,
 					   -1, 0);

 	/*
 	 * Ensure that the toast table doesn't itself get toasted, or we'll be
 	 * toast :-(.  This is essential for chunk_data because type bytea is
 	 * toastable; hit the other two just to be sure.
 	 */
 	tupdesc->attrs[0]->attstorage = 'p';
 	tupdesc->attrs[1]->attstorage = 'p';
 	tupdesc->attrs[2]->attstorage = 'p';

 	/*
 	 * Note: the toast relation is placed in the regular pg_toast namespace
 	 * even if its master relation is a temp table.  There cannot be any
 	 * naming collision, and the toast rel will be destroyed when its master
 	 * is, so there's no need to handle the toast rel as temp.
 	 *
 	 * XXX would it make sense to apply the master's reloptions to the toast
 	 * table?
 	 */
 	toast_relid = heap_create_with_catalog(toast_relname,
 										   PG_TOAST_NAMESPACE,
 										   tablespaceOid,
 										   toastOid,
 										   rel->rd_rel->relowner,
 										   tupdesc,
 										   /* relam */ InvalidOid,
 										   RELKIND_TOASTVALUE,
 										   RELSTORAGE_HEAP,
 										   shared_relation,
 										   true,
 										   /* bufferPoolBulkLoad */ false,
 										   0,
 										   ONCOMMIT_NOOP,
 										   NULL, /* CDB POLICY */
 										   (Datum) 0,
 										   true,
 										   comptypeOid,
 										   /* persistentTid */ NULL,
 										   /* persistentSerialNum */ NULL);

 	/* make the toast relation visible, else index creation will fail */
 	CommandCounterIncrement();

 	/*
 	 * Create unique index on chunk_id, chunk_seq.
 	 *
 	 * NOTE: the normal TOAST access routines could actually function with a
 	 * single-column index on chunk_id only. However, the slice access
 	 * routines use both columns for faster access to an individual chunk. In
 	 * addition, we want it to be unique as a check against the possibility of
 	 * duplicate TOAST chunk OIDs. The index might also be a little more
 	 * efficient this way, since btree isn't all that happy with large numbers
 	 * of equal keys.
 	 */

 	indexInfo = makeNode(IndexInfo);
 	indexInfo->ii_NumIndexAttrs = 2;
 	indexInfo->ii_KeyAttrNumbers[0] = 1;
 	indexInfo->ii_KeyAttrNumbers[1] = 2;
 	indexInfo->ii_Expressions = NIL;
 	indexInfo->ii_ExpressionsState = NIL;
 	indexInfo->ii_Predicate = NIL;
 	indexInfo->ii_PredicateState = NIL;
 	indexInfo->ii_Unique = true;
 	indexInfo->ii_Concurrent = false;

 	classObjectId[0] = OID_BTREE_OPS_OID;
 	classObjectId[1] = INT4_BTREE_OPS_OID;

 	toast_idxid = index_create(toast_relid, toast_idxname, toastIndexOid,
 							   indexInfo,
 							   BTREE_AM_OID,
 							   tablespaceOid,
 							   classObjectId, (Datum) 0,
 							   true, false, (Oid *) NULL, true, false, false, NULL);

 	/*
 	 * If this is a partitioned child, we can unlock since the master is
 	 * already locked.
 	 */
 	if (is_part_child)
 	{
 		UnlockRelationOid(toast_relid, ShareLock);
 		UnlockRelationOid(toast_idxid, AccessExclusiveLock);
 	}

 	/*
 	 * Store the toast table's OID in the parent relation's pg_class row
 	 */
 	class_rel = heap_open(RelationRelationId, RowExclusiveLock);

 	pcqCtx = caql_addrel(cqclr(&cqc), class_rel);

 	reltup = caql_getfirst(
 			pcqCtx,
 			cql("SELECT * FROM pg_class "
 				" WHERE oid = :1 "
 				" FOR UPDATE ",
 				ObjectIdGetDatum(relOid)));

 	if (!HeapTupleIsValid(reltup))
 		elog(ERROR, "cache lookup failed for relation %u", relOid);

 	((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid = toast_relid;

 	if (!IsBootstrapProcessingMode())
 	{
 		/* normal case, use a transactional update */
 		caql_update_current(pcqCtx, reltup);
 		/* and Update indexes (implicit) */
 	}
 	else
 	{
 		/* While bootstrapping, we cannot UPDATE, so overwrite in-place */
 		heap_inplace_update(class_rel, reltup);
 	}

 	heap_freetuple(reltup);

 	heap_close(class_rel, RowExclusiveLock);

 	/*
 	 * Register dependency from the toast table to the master, so that the
 	 * toast table will be deleted if the master is.  Skip this in bootstrap
 	 * mode.
 	 */
 	if (!IsBootstrapProcessingMode())
 	{
 		baseobject.classId = RelationRelationId;
 		baseobject.objectId = relOid;
 		baseobject.objectSubId = 0;
 		toastobject.classId = RelationRelationId;
 		toastobject.objectId = toast_relid;
 		toastobject.objectSubId = 0;

 		recordDependencyOn(&toastobject, &baseobject, DEPENDENCY_INTERNAL);
 	}

 	/*
 	 * Make changes visible
 	 */
 	CommandCounterIncrement();

 	return true;
 }

 /*
  * Check to see whether the table needs a TOAST table.	It does only if
  * (1) there are any toastable attributes, and (2) the maximum length
  * of a tuple could exceed TOAST_TUPLE_THRESHOLD.  (We don't want to
  * create a toast table for something like "f1 varchar(20)".)
  */
 bool
 RelationNeedsToastTable(Relation rel)
 {
 	int32		data_length = 0;
 	bool		maxlength_unknown = false;
 	bool		has_toastable_attrs = false;
 	TupleDesc	tupdesc;
 	Form_pg_attribute *att;
 	int32		tuple_length;
 	int			i;

 	if(RelationIsExternal(rel))
 		return false;

 	/*
 	 * in hawq, we cannot use toast table for dispatched table.
 	 */
 	if (RelationIsAoRows(rel) || RelationIsParquet(rel))
 		return false ;

 	tupdesc = rel->rd_att;
 	att = tupdesc->attrs;

 	for (i = 0; i < tupdesc->natts; i++)
 	{
 		if (att[i]->attisdropped)
 			continue;
 		data_length = att_align(data_length, att[i]->attalign);
 		if (att[i]->attlen > 0)
 		{
 			/* Fixed-length types are never toastable */
 			data_length += att[i]->attlen;
 		}
 		else
 		{
 			int32		maxlen = type_maximum_size(att[i]->atttypid,
 												   att[i]->atttypmod);

 			if (maxlen < 0)
 				maxlength_unknown = true;
 			else
 				data_length += maxlen;
 			if (att[i]->attstorage != 'p')
 				has_toastable_attrs = true;
 		}
 	}
 	if (!has_toastable_attrs)
 		return false;			/* nothing to toast? */
 	if (maxlength_unknown)
 		return true;			/* any unlimited-length attrs? */
 	tuple_length = MAXALIGN(offsetof(HeapTupleHeaderData, t_bits) +
 							BITMAPLEN(tupdesc->natts)) +
 		MAXALIGN(data_length);
 	return (tuple_length > TOAST_TUPLE_THRESHOLD);
 }
	/*-------------------------------------------------------------------------
	*
	* toasting.c
	* This file contains routines to support creation of toast tables
	*
	*
	* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
	* Portions Copyright (c) 1994, Regents of the University of California
	*
	* IDENTIFICATION
	* $PostgreSQL: pgsql/src/backend/catalog/toasting.c,v 1.3 2006/10/04 00:29:50 momjian Exp $
	*
	*-------------------------------------------------------------------------
	*/
	#include "postgres.h"

	#include "access/heapam.h"
	#include "access/tuptoaster.h"
	#include "access/xact.h"
	#include "catalog/catquery.h"
	#include "catalog/dependency.h"
	#include "catalog/heap.h"
	#include "catalog/index.h"
	#include "catalog/indexing.h"
	#include "catalog/pg_namespace.h"
	#include "catalog/pg_opclass.h"
	#include "catalog/pg_type.h"
	#include "catalog/toasting.h"
	#include "commands/tablecmds.h"
	#include "commands/tablespace.h"
	#include "miscadmin.h"
	#include "nodes/makefuncs.h"
	#include "utils/builtins.h"
	#include "utils/syscache.h"
	#include "utils/guc.h"

	#include "cdb/cdbvars.h"

	static bool create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
	Oid *comptypeOid, bool is_part_child);


	/*
	* AlterTableCreateToastTable
	* If the table needs a toast table, and doesn't already have one,
	* then create a toast table for it.
	*
	* We expect the caller to have verified that the relation is a table and have
	* already done any necessary permission checks. Callers expect this function
	* to end with CommandCounterIncrement if it makes any changes.
	*/
	void
	AlterTableCreateToastTable(Oid relOid)
	{
	Relation rel;
	bool is_part_child = !rel_needs_long_lock(relOid);

	/*
	* Grab an exclusive lock on the target table, which we will NOT release
	* until end of transaction. (This is probably redundant in all present
	* uses...)
	*/
	rel = heap_open(relOid, AccessExclusiveLock);

	/* create_toast_table does all the work */
	(void) create_toast_table(rel, InvalidOid, InvalidOid, NULL, is_part_child);

	heap_close(rel, NoLock);
	}

	void
	AlterTableCreateToastTableWithOid(Oid relOid, Oid newOid, Oid newIndexOid,
	Oid * comptypeOid, bool is_part_child)
	{
	Relation rel;

	/*
	* Grab an exclusive lock on the target table, which we will NOT release
	* until end of transaction. (This is probably redundant in all present
	* uses...)
	*/
	if (is_part_child)
	rel = heap_open(relOid, NoLock);
	else
	rel = heap_open(relOid, AccessExclusiveLock);



	/* create_toast_table does all the work */
	(void) create_toast_table(rel, newOid, newIndexOid,
	comptypeOid, is_part_child);

	heap_close(rel, NoLock);
	}


	/*
	* Create a toast table during bootstrap
	*
	* Here we need to prespecify the OIDs of the toast table and its index
	*/
	void
	BootstrapToastTable(char *relName, Oid toastOid, Oid toastIndexOid)
	{
	Relation rel;
	Oid typid;

	rel = heap_openrv(makeRangeVar(NULL /catalogname/, NULL, relName, -1), AccessExclusiveLock);

	/* Note: during bootstrap may see uncataloged relation */
	if (rel->rd_rel->relkind != RELKIND_RELATION &&
	rel->rd_rel->relkind != RELKIND_UNCATALOGED)
	ereport(ERROR,
	(errcode(ERRCODE_WRONG_OBJECT_TYPE),
	errmsg("\"%s\" is not a table",
	relName)));

	/*
	* In order to be able to support upgrade we need to be able to
	* support toast tables with fixed oids. Toast tables created
	* pre 4.0 can continue to be dynamic, but anything new must
	* be declared in pg_type.h and again here.
	*/
	switch (toastOid)
	{
	/* New Toast Tables in 4.0 */

	/* TIDYCAT_BEGIN_CODEGEN
	*/
	/*
	WARNING: DO NOT MODIFY THE FOLLOWING SECTION:
	Generated by ./tidycat.pl version 31
	on Thu Sep 1 16:43:17 2011
	*/
	/* relation id: 5033 - pg_filespace_entry 20101122 */
	case PgFileSpaceEntryToastTable:
	typid = PG_FILESPACE_ENTRY_TOAST_RELTYPE_OID;
	break;
	/* relation id: 5036 - gp_segment_configuration 20101122 */
	case GpSegmentConfigToastTable:
	typid = GP_SEGMENT_CONFIGURATION_TOAST_RELTYPE_OID;
	break;
	/* relation id: 3231 - pg_attribute_encoding 20110727 */
	case PgAttributeEncodingToastTable:
	typid = PG_ATTRIBUTE_ENCODING_TOAST_RELTYPE_OID;
	break;
	/* relation id: 3220 - pg_type_encoding 20110727 */
	case PgTypeEncodingToastTable:
	typid = PG_TYPE_ENCODING_TOAST_RELTYPE_OID;
	break;
	/* relation id: 9903 - pg_partition_encoding 20110814 */
	case PgPartitionEncodingToastTable:
	typid = PG_PARTITION_ENCODING_TOAST_RELTYPE_OID;
	break;
	/* relation id: 5080 - pg_filesystem 20120903 */
	case PgFileSystemToastTable:
	typid = PG_FILESYSTEM_TOAST_RELTYPE_OID;
	break;

	/* relation id: 7076 - pg_remote_credentials 20140205 */
	case PgRemoteCredentialsToastTable:
	typid = PG_REMOTE_CREDENTIALS_TOAST_RELTYPE_OID;
	break;

	/* relation id: 6026 - pg_resqueue 20140917 */
	case PgResQueueToastTable:
	typid = PG_RESQUEUE_TOAST_RELTYPE_OID;
	break;

	/* TIDYCAT_END_CODEGEN */

	default:
	typid = InvalidOid;
	break;
	}

	/* create_toast_table does all the work */
	if (!create_toast_table(rel, toastOid, toastIndexOid, &typid, false))
	elog(ERROR, "\"%s\" does not require a toast table",
	relName);

	heap_close(rel, NoLock);
	}


	/*
	* create_toast_table --- internal workhorse
	*
	* rel is already opened and exclusive-locked
	* toastOid and toastIndexOid are normally InvalidOid, but during
	* bootstrap they can be nonzero to specify hand-assigned OIDs
	*/
	static bool
	create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
	Oid *comptypeOid, bool is_part_child)
	{
	Oid relOid = RelationGetRelid(rel);
	HeapTuple reltup;
	TupleDesc tupdesc;
	bool shared_relation;
	Relation class_rel;
	Oid toast_relid;
	Oid toast_idxid;
	char toast_relname[NAMEDATALEN];
	char toast_idxname[NAMEDATALEN];
	IndexInfo *indexInfo;
	Oid classObjectId[2];
	ObjectAddress baseobject,
	toastobject;
	cqContext cqc;
	cqContext *pcqCtx;
	Oid tablespaceOid = ChooseTablespaceForLimitedObject(rel->rd_rel->reltablespace);

	/*
	* Is it already toasted?
	*/
	if (!gp_upgrade_mode && rel->rd_rel->reltoastrelid != InvalidOid)
	return false;

	/*
	* Check to see whether the table actually needs a TOAST table.
	*/
	if (!RelationNeedsToastTable(rel))
	return false;

	/*
	* If we're in upgrade mode, and we say we don't want a toast table
	* (by having an InvalidOid for toast Oid).
	*/
	if (gp_upgrade_mode && toastOid==InvalidOid)
	return false;

	/*
	* Toast table is shared if and only if its parent is.
	*
	* We cannot allow toasting a shared relation after initdb (because
	* there's no way to mark it toasted in other databases' pg_class).
	*/
	shared_relation = rel->rd_rel->relisshared;
	if (shared_relation && !IsBootstrapProcessingMode()&&!gp_upgrade_mode)
	ereport(ERROR,
	(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
	errmsg("shared tables cannot be toasted after initdb")));

	/*
	* Create the toast table and its index
	*/
	snprintf(toast_relname, sizeof(toast_relname),
	"pg_toast_%u", relOid);
	snprintf(toast_idxname, sizeof(toast_idxname),
	"pg_toast_%u_index", relOid);

	/* this is pretty painful... need a tuple descriptor */
	tupdesc = CreateTemplateTupleDesc(3, false);
	TupleDescInitEntry(tupdesc, (AttrNumber) 1,
	"chunk_id",
	OIDOID,
	-1, 0);
	TupleDescInitEntry(tupdesc, (AttrNumber) 2,
	"chunk_seq",
	INT4OID,
	-1, 0);
	TupleDescInitEntry(tupdesc, (AttrNumber) 3,
	"chunk_data",
	BYTEAOID,
	-1, 0);

	/*
	* Ensure that the toast table doesn't itself get toasted, or we'll be
	* toast :-(. This is essential for chunk_data because type bytea is
	* toastable; hit the other two just to be sure.
	*/
	tupdesc->attrs[0]->attstorage = 'p';
	tupdesc->attrs[1]->attstorage = 'p';
	tupdesc->attrs[2]->attstorage = 'p';

	/*
	* Note: the toast relation is placed in the regular pg_toast namespace
	* even if its master relation is a temp table. There cannot be any
	* naming collision, and the toast rel will be destroyed when its master
	* is, so there's no need to handle the toast rel as temp.
	*
	* XXX would it make sense to apply the master's reloptions to the toast
	* table?
	*/
	toast_relid = heap_create_with_catalog(toast_relname,
	PG_TOAST_NAMESPACE,
	tablespaceOid,
	toastOid,
	rel->rd_rel->relowner,
	tupdesc,
	/* relam */ InvalidOid,
	RELKIND_TOASTVALUE,
	RELSTORAGE_HEAP,
	shared_relation,
	true,
	/* bufferPoolBulkLoad */ false,
	0,
	ONCOMMIT_NOOP,
	NULL, /* CDB POLICY */
	(Datum) 0,
	true,
	comptypeOid,
	/* persistentTid */ NULL,
	/* persistentSerialNum */ NULL);

	/* make the toast relation visible, else index creation will fail */
	CommandCounterIncrement();

	/*
	* Create unique index on chunk_id, chunk_seq.
	*
	* NOTE: the normal TOAST access routines could actually function with a
	* single-column index on chunk_id only. However, the slice access
	* routines use both columns for faster access to an individual chunk. In
	* addition, we want it to be unique as a check against the possibility of
	* duplicate TOAST chunk OIDs. The index might also be a little more
	* efficient this way, since btree isn't all that happy with large numbers
	* of equal keys.
	*/

	indexInfo = makeNode(IndexInfo);
	indexInfo->ii_NumIndexAttrs = 2;
	indexInfo->ii_KeyAttrNumbers[0] = 1;
	indexInfo->ii_KeyAttrNumbers[1] = 2;
	indexInfo->ii_Expressions = NIL;
	indexInfo->ii_ExpressionsState = NIL;
	indexInfo->ii_Predicate = NIL;
	indexInfo->ii_PredicateState = NIL;
	indexInfo->ii_Unique = true;
	indexInfo->ii_Concurrent = false;

	classObjectId[0] = OID_BTREE_OPS_OID;
	classObjectId[1] = INT4_BTREE_OPS_OID;

	toast_idxid = index_create(toast_relid, toast_idxname, toastIndexOid,
	indexInfo,
	BTREE_AM_OID,
	tablespaceOid,
	classObjectId, (Datum) 0,
	true, false, (Oid *) NULL, true, false, false, NULL);

	/*
	* If this is a partitioned child, we can unlock since the master is
	* already locked.
	*/
	if (is_part_child)
	{
	UnlockRelationOid(toast_relid, ShareLock);
	UnlockRelationOid(toast_idxid, AccessExclusiveLock);
	}

	/*
	* Store the toast table's OID in the parent relation's pg_class row
	*/
	class_rel = heap_open(RelationRelationId, RowExclusiveLock);

	pcqCtx = caql_addrel(cqclr(&cqc), class_rel);

	reltup = caql_getfirst(
	pcqCtx,
	cql("SELECT * FROM pg_class "
	" WHERE oid = :1 "
	" FOR UPDATE ",
	ObjectIdGetDatum(relOid)));

	if (!HeapTupleIsValid(reltup))
	elog(ERROR, "cache lookup failed for relation %u", relOid);

	((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid = toast_relid;

	if (!IsBootstrapProcessingMode())
	{
	/* normal case, use a transactional update */
	caql_update_current(pcqCtx, reltup);
	/* and Update indexes (implicit) */
	}
	else
	{
	/* While bootstrapping, we cannot UPDATE, so overwrite in-place */
	heap_inplace_update(class_rel, reltup);
	}

	heap_freetuple(reltup);

	heap_close(class_rel, RowExclusiveLock);

	/*
	* Register dependency from the toast table to the master, so that the
	* toast table will be deleted if the master is. Skip this in bootstrap
	* mode.
	*/
	if (!IsBootstrapProcessingMode())
	{
	baseobject.classId = RelationRelationId;
	baseobject.objectId = relOid;
	baseobject.objectSubId = 0;
	toastobject.classId = RelationRelationId;
	toastobject.objectId = toast_relid;
	toastobject.objectSubId = 0;

	recordDependencyOn(&toastobject, &baseobject, DEPENDENCY_INTERNAL);
	}

	/*
	* Make changes visible
	*/
	CommandCounterIncrement();

	return true;
	}

	/*
	* Check to see whether the table needs a TOAST table. It does only if
	* (1) there are any toastable attributes, and (2) the maximum length
	* of a tuple could exceed TOAST_TUPLE_THRESHOLD. (We don't want to
	* create a toast table for something like "f1 varchar(20)".)
	*/
	bool
	RelationNeedsToastTable(Relation rel)
	{
	int32 data_length = 0;
	bool maxlength_unknown = false;
	bool has_toastable_attrs = false;
	TupleDesc tupdesc;
	Form_pg_attribute *att;
	int32 tuple_length;
	int i;

	if(RelationIsExternal(rel))
	return false;

	/*
	* in hawq, we cannot use toast table for dispatched table.
	*/
	if (RelationIsAoRows(rel) \|\| RelationIsParquet(rel))
	return false ;

	tupdesc = rel->rd_att;
	att = tupdesc->attrs;

	for (i = 0; i < tupdesc->natts; i++)
	{
	if (att[i]->attisdropped)
	continue;
	data_length = att_align(data_length, att[i]->attalign);
	if (att[i]->attlen > 0)
	{
	/* Fixed-length types are never toastable */
	data_length += att[i]->attlen;
	}
	else
	{
	int32 maxlen = type_maximum_size(att[i]->atttypid,
	att[i]->atttypmod);

	if (maxlen < 0)
	maxlength_unknown = true;
	else
	data_length += maxlen;
	if (att[i]->attstorage != 'p')
	has_toastable_attrs = true;
	}
	}
	if (!has_toastable_attrs)
	return false; /* nothing to toast? */
	if (maxlength_unknown)
	return true; /* any unlimited-length attrs? */
	tuple_length = MAXALIGN(offsetof(HeapTupleHeaderData, t_bits) +
	BITMAPLEN(tupdesc->natts)) +
	MAXALIGN(data_length);
	return (tuple_length > TOAST_TUPLE_THRESHOLD);
	}