postgres.git / summary / log / commit / refs

commit    5ecd0183fb6afa4a07aad71ea0e08c70f64a42a9
Author:   Michael Paquier <michael@paquier.xyz>
Date:     Sat Jan 29 01:47:36 2022 +0000

    Fix comments about bgworker registration before MaxBackends initialization
    
    Since 6bc8ef0b, InitializeMaxBackends() has used max_worker_processes
    instead of adapting MaxBackends to the number of background workers
    registered by modules loaded in shared_preload_libraries (at this time,
    bgworkers were only static, but gained dynamic capabilities as a matter
    of supporting parallel queries meaning that a control cap was
    necessary).
    
    Some comments referred to the past registration logic, making them
    confusing and incorrect, so fix these.
    
    Some of the out-of-core modules that could be loaded in this path
    sometimes like to manipulate dynamically some of the resource-related
    GUCs for their own needs, this commit adds a note about that.
    
    Author: Nathan Bossart
    Discussion: https://postgr.es/m/20220127181815.GA551692@nathanxps13


 src/backend/postmaster/postmaster.c | 10 ++++------
 src/backend/utils/init/postinit.c   |  5 ++---
 2 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index dc4afdd75ae..ac0ec0986a2 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -1014,10 +1014,8 @@ PostmasterMain(int argc, char *argv[])
 	LocalProcessControlFile(false);
 
 	/*
-	 * Register the apply launcher.  Since it registers a background worker,
-	 * it needs to be called before InitializeMaxBackends(), and it's probably
-	 * a good idea to call it before any modules had chance to take the
-	 * background worker slots.
+	 * Register the apply launcher.  It's probably a good idea to call this
+	 * before any modules had a chance to take the background worker slots.
 	 */
 	ApplyLauncherRegister();
 
@@ -1038,8 +1036,8 @@ PostmasterMain(int argc, char *argv[])
 #endif
 
 	/*
-	 * Now that loadable modules have had their chance to register background
-	 * workers, calculate MaxBackends.
+	 * Now that loadable modules have had their chance to alter any GUCs,
+	 * calculate MaxBackends.
 	 */
 	InitializeMaxBackends();
 
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index d046caabd7d..cd7c829ff5d 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -483,9 +483,8 @@ pg_split_opts(char **argv, int *argcp, const char *optstr)
 /*
  * Initialize MaxBackends value from config options.
  *
- * This must be called after modules have had the chance to register background
- * workers in shared_preload_libraries, and before shared memory size is
- * determined.
+ * This must be called after modules have had the chance to alter GUCs in
+ * shared_preload_libraries and before shared memory size is determined.
  *
  * Note that in EXEC_BACKEND environment, the value is passed down from
  * postmaster to subprocesses via BackendParameters in SubPostmasterMain; only


[parent: bf42fcace5c5]