v6-0002-Assign-backend-type-earlier.patch

From 25204568735906a01004bf5c33096dfddb67a2c0 Mon Sep 17 00:00:00 2001
From: Euler Taveira <euler@eulerto.com>
Date: Tue, 25 Nov 2025 21:09:11 -0300
Subject: [PATCH v6 2/2] Assign backend type earlier

Instead of assigning the backend type into the Main function of each
postmaster child, do it earlier (after fork()). The backend type is
already known by postmaster_child_launch() before it calls fork(). This
reduces the time frame that MyBackendType is correct. (This is important
for log_min_messages per backend type that relies on a known
MyBackendType to decide if it writes a log message or not.)
---
 src/backend/postmaster/autovacuum.c        | 2 --
 src/backend/postmaster/bgworker.c          | 1 -
 src/backend/postmaster/bgwriter.c          | 1 -
 src/backend/postmaster/checkpointer.c      | 1 -
 src/backend/postmaster/launch_backend.c    | 2 ++
 src/backend/postmaster/pgarch.c            | 1 -
 src/backend/postmaster/startup.c           | 1 -
 src/backend/postmaster/syslogger.c         | 1 -
 src/backend/postmaster/walsummarizer.c     | 1 -
 src/backend/postmaster/walwriter.c         | 1 -
 src/backend/replication/logical/slotsync.c | 2 --
 src/backend/replication/walreceiver.c      | 1 -
 src/backend/storage/aio/method_worker.c    | 1 -
 13 files changed, 2 insertions(+), 14 deletions(-)

diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 1c38488f2cb..36c1911a3a8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -388,7 +388,6 @@ AutoVacLauncherMain(const void *startup_data, size_t startup_data_len)
 		PostmasterContext = NULL;
 	}
 
-	MyBackendType = B_AUTOVAC_LAUNCHER;
 	init_ps_display(NULL);
 
 	ereport(DEBUG1,
@@ -1401,7 +1400,6 @@ AutoVacWorkerMain(const void *startup_data, size_t startup_data_len)
 		PostmasterContext = NULL;
 	}
 
-	MyBackendType = B_AUTOVAC_WORKER;
 	init_ps_display(NULL);
 
 	Assert(GetProcessingMode() == InitProcessing);
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 142a02eb5e9..260f051711e 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -741,7 +741,6 @@ BackgroundWorkerMain(const void *startup_data, size_t startup_data_len)
 	}
 
 	MyBgworkerEntry = worker;
-	MyBackendType = B_BG_WORKER;
 	init_ps_display(worker->bgw_name);
 
 	Assert(GetProcessingMode() == InitProcessing);
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 72f5acceec7..4119758a72c 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -94,7 +94,6 @@ BackgroundWriterMain(const void *startup_data, size_t startup_data_len)
 
 	Assert(startup_data_len == 0);
 
-	MyBackendType = B_BG_WRITER;
 	AuxiliaryProcessMainCommon();
 
 	/*
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index e84e8663e96..32e849bea15 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -199,7 +199,6 @@ CheckpointerMain(const void *startup_data, size_t startup_data_len)
 
 	Assert(startup_data_len == 0);
 
-	MyBackendType = B_CHECKPOINTER;
 	AuxiliaryProcessMainCommon();
 
 	CheckpointerShmem->checkpointer_pid = MyProcPid;
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index c2a044321d1..35420b8c9fb 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -224,6 +224,8 @@ postmaster_child_launch(BackendType child_type, int child_slot,
 	pid = fork_process();
 	if (pid == 0)				/* child */
 	{
+		MyBackendType = child_type;
+
 		/* Capture and transfer timings that may be needed for logging */
 		if (IsExternalConnectionBackend(child_type))
 		{
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index ce6b5299324..b760d1aed40 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -222,7 +222,6 @@ PgArchiverMain(const void *startup_data, size_t startup_data_len)
 {
 	Assert(startup_data_len == 0);
 
-	MyBackendType = B_ARCHIVER;
 	AuxiliaryProcessMainCommon();
 
 	/*
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 27e86cf393f..13e86a2921e 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -217,7 +217,6 @@ StartupProcessMain(const void *startup_data, size_t startup_data_len)
 {
 	Assert(startup_data_len == 0);
 
-	MyBackendType = B_STARTUP;
 	AuxiliaryProcessMainCommon();
 
 	/* Arrange to clean up at startup process exit */
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 50c2edec1f6..a378b15a6de 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -206,7 +206,6 @@ SysLoggerMain(const void *startup_data, size_t startup_data_len)
 
 	now = MyStartTime;
 
-	MyBackendType = B_LOGGER;
 	init_ps_display(NULL);
 
 	/*
diff --git a/src/backend/postmaster/walsummarizer.c b/src/backend/postmaster/walsummarizer.c
index c4a888a081c..ce497d8ec42 100644
--- a/src/backend/postmaster/walsummarizer.c
+++ b/src/backend/postmaster/walsummarizer.c
@@ -234,7 +234,6 @@ WalSummarizerMain(const void *startup_data, size_t startup_data_len)
 
 	Assert(startup_data_len == 0);
 
-	MyBackendType = B_WAL_SUMMARIZER;
 	AuxiliaryProcessMainCommon();
 
 	ereport(DEBUG1,
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index fd92c8b7a33..c1b4ddda555 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -94,7 +94,6 @@ WalWriterMain(const void *startup_data, size_t startup_data_len)
 
 	Assert(startup_data_len == 0);
 
-	MyBackendType = B_WAL_WRITER;
 	AuxiliaryProcessMainCommon();
 
 	/*
diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c
index 1f4f06d467b..c9069f299b6 100644
--- a/src/backend/replication/logical/slotsync.c
+++ b/src/backend/replication/logical/slotsync.c
@@ -1403,8 +1403,6 @@ ReplSlotSyncWorkerMain(const void *startup_data, size_t startup_data_len)
 
 	Assert(startup_data_len == 0);
 
-	MyBackendType = B_SLOTSYNC_WORKER;
-
 	init_ps_display(NULL);
 
 	Assert(GetProcessingMode() == InitProcessing);
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 4217fc54e2e..fe35cacb95c 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -168,7 +168,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len)
 
 	Assert(startup_data_len == 0);
 
-	MyBackendType = B_WAL_RECEIVER;
 	AuxiliaryProcessMainCommon();
 
 	/*
diff --git a/src/backend/storage/aio/method_worker.c b/src/backend/storage/aio/method_worker.c
index b5ac073a910..fee1dae7e2d 100644
--- a/src/backend/storage/aio/method_worker.c
+++ b/src/backend/storage/aio/method_worker.c
@@ -391,7 +391,6 @@ IoWorkerMain(const void *startup_data, size_t startup_data_len)
 	volatile int error_errno = 0;
 	char		cmd[128];
 
-	MyBackendType = B_IO_WORKER;
 	AuxiliaryProcessMainCommon();
 
 	pqsignal(SIGHUP, SignalHandlerForConfigReload);
-- 
2.39.5