Handle HASHPROC changes

PostgreSQL 11 now has "standard" and "extended" (64-bit) versions of
hash functions.

src/backend/distributed/commands/create_distributed_table.c

@@ -636,7 +636,8 @@ EnsureRelationCanBeDistributed(Oid relationId, Var *distributionColumn,
 	if (distributionMethod == DISTRIBUTE_BY_HASH)
 	{
 		Oid hashSupportFunction = SupportFunctionForColumn(distributionColumn,
-														   HASH_AM_OID, HASHPROC);
+														   HASH_AM_OID,
+														   HASHSTANDARD_PROC);
 		if (hashSupportFunction == InvalidOid)
 		{
 			ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION),

src/backend/distributed/worker/worker_partition_protocol.c

@@ -35,6 +35,7 @@
 #include "distributed/resource_lock.h"
 #include "distributed/transmit.h"
 #include "distributed/worker_protocol.h"
+#include "distributed/version_compat.h"
 #include "executor/spi.h"
 #include "mb/pg_wchar.h"
 #include "storage/lmgr.h"
@@ -191,7 +192,7 @@ worker_hash_partition_table(PG_FUNCTION_ARGS)
 	CheckCitusVersion(ERROR);
 
 	/* use column's type information to get the hashing function */
-	hashFunction = GetFunctionInfo(partitionColumnType, HASH_AM_OID, HASHPROC);
+	hashFunction = GetFunctionInfo(partitionColumnType, HASH_AM_OID, HASHSTANDARD_PROC);
 
 	/* create hash partition context object */
 	partitionContext = palloc0(sizeof(HashPartitionContext));

src/include/distributed/version_compat.h

@@ -21,4 +21,13 @@
 
 #endif
 
+#if (PG_VERSION_NUM >= 90600 && PG_VERSION_NUM < 110000)
+
+#include "access/hash.h"
+
+/* PostgreSQL 11 splits hash procs into "standard" and "extended" */
+#define HASHSTANDARD_PROC HASHPROC
+
+#endif
+
 #endif   /* VERSION_COMPAT_H */