From fba4e65b95564454824d43a851bf1c7578320570 Mon Sep 17 00:00:00 2001
From: gurkanindibay <gindibay@microsoft.com>
Date: Tue, 26 Dec 2023 23:57:16 +0300
Subject: [PATCH] Adds dist_database to metadata cache

---
 .../distributed/commands/citus_database_size.c       |  2 +-
 src/backend/distributed/metadata/metadata_cache.c    | 12 ++++++++++++
 src/include/distributed/metadata_cache.h             |  1 +
 src/include/distributed/pg_dist_database.h           |  2 --
 4 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/backend/distributed/commands/citus_database_size.c b/src/backend/distributed/commands/citus_database_size.c
index 35a1e46fe3f..10fe813760a 100644
--- a/src/backend/distributed/commands/citus_database_size.c
+++ b/src/backend/distributed/commands/citus_database_size.c
@@ -188,7 +188,7 @@ GroupLookupFromDatabase(int64 databaseOid, bool missingOk)
 	ScanKeyData scanKey[1];
 	int scanKeyCount = 1;
 	Form_pg_dist_database databaseForm = NULL;
-	Relation pgDistDatabase = table_open(PgDistDatabaseRelationId(), AccessShareLock);
+	Relation pgDistDatabase = table_open(DistDatabaseRelationId(), AccessShareLock);
 	int groupId = -1;
 
 	ScanKeyInit(&scanKey[0], Anum_pg_dist_database_databaseid,
diff --git a/src/backend/distributed/metadata/metadata_cache.c b/src/backend/distributed/metadata/metadata_cache.c
index 1b2fa229f42..05a63c7084c 100644
--- a/src/backend/distributed/metadata/metadata_cache.c
+++ b/src/backend/distributed/metadata/metadata_cache.c
@@ -192,6 +192,7 @@ typedef struct MetadataCacheData
 	Oid distCleanupPrimaryKeyIndexId;
 	Oid distColocationRelationId;
 	Oid distColocationConfigurationIndexId;
+	Oid distDatabaseRelationId;
 	Oid distPartitionRelationId;
 	Oid distTenantSchemaRelationId;
 	Oid distPartitionLogicalRelidIndexId;
@@ -2903,6 +2904,17 @@ DistColocationConfigurationIndexId(void)
 }
 
 
+/* return oid of pg_dist_database relation */
+Oid
+DistDatabaseRelationId(void)
+{
+	CachedRelationLookup("pg_dist_database",
+						 &MetadataCache.distDatabaseRelationId);
+
+	return MetadataCache.distDatabaseRelationId;
+}
+
+
 /* return oid of pg_dist_schema relation */
 Oid
 DistTenantSchemaRelationId(void)
diff --git a/src/include/distributed/metadata_cache.h b/src/include/distributed/metadata_cache.h
index f1120497b72..a8a70592d77 100644
--- a/src/include/distributed/metadata_cache.h
+++ b/src/include/distributed/metadata_cache.h
@@ -238,6 +238,7 @@ extern Oid CitusCatalogNamespaceId(void);
 extern Oid DistCleanupRelationId(void);
 extern Oid DistColocationRelationId(void);
 extern Oid DistColocationConfigurationIndexId(void);
+extern Oid DistDatabaseRelationId(void);
 extern Oid DistPartitionRelationId(void);
 extern Oid DistShardRelationId(void);
 extern Oid DistPlacementRelationId(void);
diff --git a/src/include/distributed/pg_dist_database.h b/src/include/distributed/pg_dist_database.h
index 12983b94eab..5555965b754 100644
--- a/src/include/distributed/pg_dist_database.h
+++ b/src/include/distributed/pg_dist_database.h
@@ -31,6 +31,4 @@ typedef struct FormData_pg_dist_database
 typedef FormData_pg_dist_database *Form_pg_dist_database;
 
 
-#define PgDistDatabaseRelationId() (get_relname_relid("pg_dist_database", \
-													  PG_CATALOG_NAMESPACE))
 #endif /* CITUS_PG_DIST_DATABASE_H */