From ab080cad930a4c8c1592ec5c93c423f3ede45f36 Mon Sep 17 00:00:00 2001
From: Jelte Fennema <github-tech@jeltef.nl>
Date: Tue, 3 Jan 2023 10:24:01 +0100
Subject: [PATCH] Fix bug introduced by #6412

In #6412 I made a change to not re-assign the global PID if it was
already set. This inadvertently introduced a regression where `userId`
and `databaseId` would not be set on the backend data when the global
PID was assigned in the authentication hook.

This fixes it by doing two things:
1. Removing `userId` from `BackendData`, since it's not used anywhere
   anyway.
2. Move assignment of `databaseId` to InitializeBackendData.
---
 src/backend/distributed/shared_library_init.c      | 1 +
 src/backend/distributed/transaction/backend_data.c | 6 +-----
 src/include/distributed/backend_data.h             | 2 +-
 3 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/src/backend/distributed/shared_library_init.c b/src/backend/distributed/shared_library_init.c
index c15268056..df361b251 100644
--- a/src/backend/distributed/shared_library_init.c
+++ b/src/backend/distributed/shared_library_init.c
@@ -678,6 +678,7 @@ StartupCitusBackend(void)
 	 * the gpid from the application_name.
 	 */
 	AssignGlobalPID();
+
 	RegisterConnectionCleanup();
 }
 
diff --git a/src/backend/distributed/transaction/backend_data.c b/src/backend/distributed/transaction/backend_data.c
index 3daebc6e8..37e0930b9 100644
--- a/src/backend/distributed/transaction/backend_data.c
+++ b/src/backend/distributed/transaction/backend_data.c
@@ -717,6 +717,7 @@ InitializeBackendData(const char *applicationName)
 	SpinLockAcquire(&MyBackendData->mutex);
 	MyBackendData->distributedCommandOriginator = IsExternalClientBackend();
 	MyBackendData->globalPID = gpid;
+	MyBackendData->databaseId = MyDatabaseId;
 	SpinLockRelease(&MyBackendData->mutex);
 
 	/*
@@ -765,7 +766,6 @@ UnSetGlobalPID(void)
 
 		MyBackendData->globalPID = 0;
 		MyBackendData->databaseId = 0;
-		MyBackendData->userId = 0;
 		MyBackendData->distributedCommandOriginator = false;
 
 		SpinLockRelease(&MyBackendData->mutex);
@@ -923,14 +923,10 @@ AssignGlobalPID(void)
 		globalPID = ExtractGlobalPID(application_name);
 	}
 
-	Oid userId = GetUserId();
-
 	SpinLockAcquire(&MyBackendData->mutex);
 
 	MyBackendData->globalPID = globalPID;
 	MyBackendData->distributedCommandOriginator = distributedCommandOriginator;
-	MyBackendData->databaseId = MyDatabaseId;
-	MyBackendData->userId = userId;
 
 	SpinLockRelease(&MyBackendData->mutex);
 }
diff --git a/src/include/distributed/backend_data.h b/src/include/distributed/backend_data.h
index b0846c8a7..0b1ee0644 100644
--- a/src/include/distributed/backend_data.h
+++ b/src/include/distributed/backend_data.h
@@ -36,7 +36,6 @@
 typedef struct BackendData
 {
 	Oid databaseId;
-	Oid userId;
 	slock_t mutex;
 	bool cancelledDueToDeadlock;
 	uint64 globalPID;
@@ -60,6 +59,7 @@ extern void AssignDistributedTransactionId(void);
 extern void AssignGlobalPID(void);
 extern void SetBackendDataGlobalPID(uint64 globalPID);
 extern uint64 GetGlobalPID(void);
+extern void SetBackendDataAfterAuthData(void);
 extern void SetBackendDataDistributedCommandOriginator(bool
 													   distributedCommandOriginator);
 extern uint64 ExtractGlobalPID(const char *applicationName);