Subject: [PATCH v7 2/3] Assign backend type earlier

From: Euler Taveira <[email-masked]>
Date: Tue, 25 Nov 2025 21:09:11 -0300

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 afb3d6d8630..427f50752d4 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 7e3b4c4413e..364df1ad519 100644
--- a/src/backend/replication/logical/slotsync.c
+++ b/src/backend/replication/logical/slotsync.c
@@ -1436,8 +1436,6 @@ 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 3a94c9683a7..154fe9e0cb5 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 866a35abbd1..64caaa7b766 100644
--- a/src/backend/storage/aio/method_worker.c
+++ b/src/backend/storage/aio/method_worker.c
@@ -390,7 +390,6 @@ 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);
-- 
2.47.3

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