implement splits when a target colocation has been set

src/backend/distributed/commands/citus_add_local_table_to_metadata.c

@@ -1406,6 +1406,7 @@ InsertMetadataForCitusLocalTable(Oid citusLocalTableId, uint64 shardId,
 	char replicationModel = REPLICATION_MODEL_STREAMING;
 
 	uint32 colocationId = INVALID_COLOCATION_ID;
+	int64 shardgroupId = INVALID_SHARDGROUP_ID;
 	Var *distributionColumn = NULL;
 	InsertIntoPgDistPartition(citusLocalTableId, distributionMethod,
 							  distributionColumn, colocationId,
@@ -1417,7 +1418,7 @@ InsertMetadataForCitusLocalTable(Oid citusLocalTableId, uint64 shardId,
 	text *shardMinValue = NULL;
 	text *shardMaxValue = NULL;
 	InsertShardRow(citusLocalTableId, shardId, shardStorageType,
-				   shardMinValue, shardMaxValue, NULL);
+				   shardMinValue, shardMaxValue, &shardgroupId);
 
 	List *nodeList = list_make1(CoordinatorNodeIfAddedAsWorkerOrError());
 

src/backend/distributed/metadata/metadata_cache.c

@@ -2885,6 +2885,14 @@ DistShardgroupPkeyId(void)
 }
 
 
+Oid
+DistShardgroupColocaionidIndexId(void)
+{
+	/* TODO add index on colocation id */
+	return InvalidOid;
+}
+
+
 /* return oid of pg_dist_placement_shardid_index */
 Oid
 DistPlacementShardidIndexId(void)

src/backend/distributed/metadata/metadata_sync.c

@@ -1409,10 +1409,10 @@ ShardgroupInsertCommand(List *shardgroups)
 		appendStringInfo(&command, "(%ld, %d, %s, %s)",
 						 shardgroup->shardgroupId,
 						 shardgroup->colocationId,
-						 TextToSQLLiteral(IntegerToText(
+						 shardgroup->minShardValue == NULL ? "NULL" : quote_literal_cstr(
-											  DatumGetInt32(shardgroup->minShardValue))),
+							 shardgroup->minShardValue),
-						 TextToSQLLiteral(IntegerToText(
+						 shardgroup->maxShardValue == NULL ? "NULL" : quote_literal_cstr(
-											  DatumGetInt32(shardgroup->maxShardValue))));
+							 shardgroup->maxShardValue));
 	}
 	appendStringInfo(&command, ") ");
 

src/backend/distributed/operations/create_shards.c

@@ -494,14 +494,21 @@ CheckHashPartitionedTable(Oid distributedTableId)
 }
 
 
-/* Helper function to convert an integer value to a text type */
+char *
-text *
+IntegerToCStr(int32 value)
-IntegerToText(int32 value)
 {
 	StringInfo valueString = makeStringInfo();
 	appendStringInfo(valueString, "%d", value);
 
-	text *valueText = cstring_to_text(valueString->data);
+	return valueString->data;
+}
+
+
+/* Helper function to convert an integer value to a text type */
+text *
+IntegerToText(int32 value)
+{
+	text *valueText = cstring_to_text(IntegerToCStr(value));
 
 	return valueText;
 }

src/backend/distributed/operations/shard_split.c

@@ -44,6 +44,7 @@
 #include "distributed/shardsplit_logical_replication.h"
 #include "distributed/deparse_shard_query.h"
 #include "distributed/shard_rebalancer.h"
+#include "distributed/shardgroup.h"
 #include "postmaster/postmaster.h"
 
 /*
@@ -129,7 +130,8 @@ static void UpdateDistributionColumnsForShardGroup(List *colocatedShardList,
 												   DistributionColumnMap *distCols,
 												   char distributionMethod,
 												   int shardCount,
-												   uint32 colocationId);
+												   uint32 colocationId,
+												   List **shardgroupSplits);
 static void InsertSplitChildrenShardgroupMetadata(List *newShardgroups);
 static void InsertSplitChildrenShardMetadata(List *shardGroupSplitIntervalListList,
 											 List *workersForPlacementList);
@@ -1066,11 +1068,11 @@ CreateNewShardgroups(uint32 colocationId, ShardInterval *sampleInterval,
 		Shardgroup *shardgroup = palloc0(sizeof(Shardgroup));
 		shardgroup->shardgroupId = GetNextShardgroupIdForSplitChild();
 		shardgroup->colocationId = colocationId;
-		shardgroup->minShardValue = Int32GetDatum(currentSplitChildMinValue);
+		shardgroup->minShardValue = IntegerToCStr(currentSplitChildMinValue);
-		shardgroup->maxShardValue = splitPoint;
+		shardgroup->maxShardValue = IntegerToCStr(DatumGetInt32(splitPoint));
 
 		/* increment for next shardgroup */
-		currentSplitChildMinValue = Int32GetDatum(DatumGetInt32(splitPoint) + 1);
+		currentSplitChildMinValue = DatumGetInt32(splitPoint) + 1;
 		newShardgroups = lappend(newShardgroups, shardgroup);
 	}
 
@@ -1083,8 +1085,8 @@ CreateNewShardgroups(uint32 colocationId, ShardInterval *sampleInterval,
 	Shardgroup *shardgroup = palloc0(sizeof(Shardgroup));
 	shardgroup->shardgroupId = GetNextShardgroupIdForSplitChild();
 	shardgroup->colocationId = colocationId;
-	shardgroup->minShardValue = Int32GetDatum(currentSplitChildMinValue);
+	shardgroup->minShardValue = IntegerToCStr(currentSplitChildMinValue);
-	shardgroup->maxShardValue = splitParentMaxValue;
+	shardgroup->maxShardValue = IntegerToCStr(DatumGetInt32(splitParentMaxValue));
 	newShardgroups = lappend(newShardgroups, shardgroup);
 
 	return newShardgroups;
@@ -1135,9 +1137,12 @@ CreateShardIntervalsForNewShardgroups(ShardInterval *sourceShard,
 		splitChildShardInterval->shardId = GetNextShardIdForSplitChild();
 		splitChildShardInterval->shardGroupId = shardgroup->shardgroupId;
 		splitChildShardInterval->minValueExists = true;
-		splitChildShardInterval->minValue = shardgroup->minShardValue;
+		splitChildShardInterval->minValue =
+			Int32GetDatum(pg_strtoint32(shardgroup->minShardValue));
 		splitChildShardInterval->maxValueExists = true;
-		splitChildShardInterval->maxValue = shardgroup->maxShardValue;
+		splitChildShardInterval->maxValue =
+			Int32GetDatum(pg_strtoint32(shardgroup->maxShardValue));
+
 
 		shardSplitChildrenIntervalList = lappend(shardSplitChildrenIntervalList,
 												 splitChildShardInterval);
@@ -1165,8 +1170,25 @@ UpdateDistributionColumnsForShardGroup(List *colocatedShardList,
 									   DistributionColumnMap *distributionColumnMap,
 									   char distributionMethod,
 									   int shardCount,
-									   uint32 colocationId)
+									   uint32 colocationId,
+									   List **shardgroupSplits)
 {
+	if (colocationId != INVALID_COLOCATION_ID)
+	{
+		/*
+		 * We know we are colocating the shards with already existing shards in their
+		 * respective shardgroups. To prevent the new groups from being inserted we forget
+		 * them here.
+		 */
+
+		*shardgroupSplits = NIL;
+
+		/*
+		 * TODO make sure we have either already used the existing shardgroup id's or
+		 * update the newly created shards to have to correct shardgroup id's
+		 */
+	}
+
 	ShardInterval *shardInterval = NULL;
 	foreach_ptr(shardInterval, colocatedShardList)
 	{
@@ -1187,6 +1209,13 @@ UpdateDistributionColumnsForShardGroup(List *colocatedShardList,
 												 ShardReplicationFactor,
 												 distributionColumn->vartype,
 												 distributionColumn->varcollid);
+
+			/* Update the shardgroup splits with the newly assigned colocation id */
+			Shardgroup *shardgroup = NULL;
+			foreach_ptr(shardgroup, *shardgroupSplits)
+			{
+				shardgroup->colocationId = colocationId;
+			}
 		}
 
 		UpdateDistributionColumnGlobally(relationId, distributionMethod,
@@ -1198,14 +1227,19 @@ UpdateDistributionColumnsForShardGroup(List *colocatedShardList,
 static void
 InsertSplitChildrenShardgroupMetadata(List *newShardgroups)
 {
+	if (list_length(newShardgroups) <= 0)
+	{
+		return;
+	}
+
 	Shardgroup *shardgroup = NULL;
 	foreach_ptr(shardgroup, newShardgroups)
 	{
 		InsertShardGroupRow(
 			shardgroup->shardgroupId,
 			shardgroup->colocationId,
-			IntegerToText(DatumGetInt32(shardgroup->minShardValue)),
+			cstring_to_text(shardgroup->minShardValue),
-			IntegerToText(DatumGetInt32(shardgroup->maxShardValue)));
+			cstring_to_text(shardgroup->maxShardValue));
 	}
 
 	if (/* TODO check if shardgroup needs to propagate */ true)
@@ -1479,10 +1513,23 @@ NonBlockingShardSplit(SplitOperation splitOperation,
 	char *superUser = CitusExtensionOwnerName();
 	char *databaseName = get_database_name(MyDatabaseId);
 
-	List *shardgroupSplits = CreateNewShardgroups(
+	List *shardgroupSplits = NIL;
+	if (targetColocationId == INVALID_COLOCATION_ID)
+	{
+		shardgroupSplits = CreateNewShardgroups(
 			colocationId,
 			(ShardInterval *) linitial(sourceColocatedShardIntervalList),
 			shardSplitPointsList);
+	}
+	else
+	{
+		/*
+		 * We are distributing a new table onto an existing colocation id, load
+		 * shardgroupSplits from there.
+		 */
+
+		shardgroupSplits = ShardgroupForColocationId(targetColocationId);
+	}
 
 	/* First create shard interval metadata for split children */
 	List *shardGroupSplitIntervalListList = CreateSplitIntervalsForShardGroup(
@@ -1685,7 +1732,9 @@ NonBlockingShardSplit(SplitOperation splitOperation,
 											   distributionColumnOverrides,
 											   distributionMethod,
 											   shardCount,
-											   targetColocationId);
+											   targetColocationId,
+											   &shardgroupSplits);
+	}
 
 	/* 12) Insert new shardgroup, shard and placement metadata */
 	InsertSplitChildrenShardgroupMetadata(shardgroupSplits);

src/backend/distributed/sql/downgrades/citus--11.3-1--11.2-1.sql

@@ -1,7 +1,7 @@
 -- citus--11.3-1--11.2-1
 -- this is an empty downgrade path since citus--11.2-1--11.3-1.sql is empty for now
 DROP TABLE pg_catalog.pg_dist_shardgroup;
-DROP SEQUENCE citus.pg_dist_shardgroupid_seq;
+DROP SEQUENCE pg_catalog.pg_dist_shardgroupid_seq;
 
 ALTER TABLE pg_catalog.pg_dist_shard DROP COLUMN shardgroupid;
 
@@ -9,4 +9,4 @@ DROP FUNCTION pg_catalog.citus_internal_add_shard_metadata(regclass, bigint, "ch
 #include "../udfs/citus_internal_add_shard_metadata/10.2-1.sql"
 
 DROP FUNCTION pg_catalog.citus_internal_add_shardgroup_metadata(bigint, integer, text, text);
-DROP FUNCTION FUNCTION pg_catalog.citus_internal_delete_shardgroup_metadata(bigint, int);
+DROP FUNCTION pg_catalog.citus_internal_delete_shardgroup_metadata(bigint, int);

src/backend/distributed/utils/shardgroup.c

@@ -0,0 +1,68 @@
+/*-------------------------------------------------------------------------
+ *
+ * shardgroup.c
+ *
+ * This file contains functions to perform useful operations on shardgroups.
+ *
+ * Copyright (c) Citus Data, Inc.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/genam.h"
+#include "utils/fmgroids.h"
+#include "access/skey.h"
+#include "utils/relcache.h"
+#include "storage/lockdefs.h"
+#include "utils/builtins.h"
+
+#include "distributed/listutils.h"
+#include "distributed/shardgroup.h"
+#include "distributed/pg_dist_shardgroup.h"
+#include "distributed/metadata_cache.h"
+
+List *
+ShardgroupForColocationId(uint32 colocationId)
+{
+	ScanKeyData scanKey[1] = { 0 };
+	Form_pg_dist_shardgroup shardgroupForm = NULL;
+	Relation pgDistShardgroup = table_open(DistShardgroupRelationId(), AccessShareLock);
+	TupleDesc tupleDescriptor = RelationGetDescr(pgDistShardgroup);
+
+	ScanKeyInit(&scanKey[0], Anum_pg_dist_shardgroup_colocationid,
+				BTEqualStrategyNumber, F_INT4EQ, UInt32GetDatum(colocationId));
+
+	SysScanDesc scanDescriptor =
+		systable_beginscan(pgDistShardgroup, DistShardgroupColocaionidIndexId(), true,
+						   NULL, lengthof(scanKey), scanKey);
+
+	HeapTuple heapTuple = NULL;
+	List *shardgroups = NIL;
+	while (HeapTupleIsValid(heapTuple = systable_getnext(scanDescriptor)))
+	{
+		Datum datumArray[Natts_pg_dist_shardgroup] = { 0 };
+		bool isNullArray[Natts_pg_dist_shardgroup] = { 0 };
+		heap_deform_tuple(heapTuple, tupleDescriptor, datumArray, isNullArray);
+		shardgroupForm = (Form_pg_dist_shardgroup) GETSTRUCT(heapTuple);
+
+		Shardgroup *shardgroup = palloc0(sizeof(Shardgroup));
+		shardgroup->shardgroupId = shardgroupForm->shardgroupid;
+		shardgroup->colocationId = shardgroupForm->colocationid;
+
+		/* load shard min/max values */
+		Datum minValueTextDatum = datumArray[Anum_pg_dist_shardgroup_shardminvalue - 1];
+		Datum maxValueTextDatum = datumArray[Anum_pg_dist_shardgroup_shardmaxvalue - 1];
+		shardgroup->minShardValue = TextDatumGetCString(minValueTextDatum);
+		shardgroup->maxShardValue = TextDatumGetCString(maxValueTextDatum);
+
+
+		shardgroups = lappend(shardgroups, shardgroup);
+	}
+
+	systable_endscan(scanDescriptor);
+	table_close(pgDistShardgroup, NoLock);
+
+	return shardgroups;
+}

src/include/distributed/coordinator_protocol.h

@@ -274,6 +274,7 @@ extern Oid ForeignConstraintGetReferencedTableId(const char *queryString);
 extern void CheckHashPartitionedTable(Oid distributedTableId);
 extern void CheckTableSchemaNameForDrop(Oid relationId, char **schemaName,
 										char **tableName);
+extern char * IntegerToCStr(int32 value);
 extern text * IntegerToText(int32 value);
 
 /* Function declarations for generating metadata for shard and placement creation */

src/include/distributed/metadata_cache.h

@@ -253,6 +253,7 @@ extern Oid DistBackgroundTaskDependDependsOnIndexId(void);
 extern Oid DistShardLogicalRelidIndexId(void);
 extern Oid DistShardShardidIndexId(void);
 extern Oid DistShardgroupPkeyId(void);
+extern Oid DistShardgroupColocaionidIndexId(void);
 extern Oid DistPlacementShardidIndexId(void);
 extern Oid DistPlacementPlacementidIndexId(void);
 extern Oid DistColocationIndexId(void);

src/include/distributed/metadata_utility.h

@@ -75,8 +75,8 @@ typedef struct Shardgroup
 {
 	int64 shardgroupId;
 	uint32 colocationId;
-	Datum minShardValue; /* a shard's typed min value datum */
+	const char *minShardValue;
-	Datum maxShardValue; /* a shard's typed max value datum */
+	const char *maxShardValue;
 } Shardgroup;
 
 

src/include/distributed/relay_utility.h

@@ -23,6 +23,7 @@
 /* Shard name and identifier related defines */
 #define SHARD_NAME_SEPARATOR '_'
 #define INVALID_SHARD_ID 0
+#define INVALID_SHARDGROUP_ID 0
 #define INVALID_PLACEMENT_ID 0
 
 

src/include/distributed/shardgroup.h

@@ -0,0 +1,11 @@
+
+#ifndef CITUS_SHARDGROUP_H
+#define CITUS_SHARDGROUP_H
+
+#include "postgres.h"
+
+#include "distributed/listutils.h"
+
+extern List * ShardgroupForColocationId(uint32 colocationId);
+
+#endif /*CITUS_SHARDGROUP_H */