Create a "shmem_startup_hook" to be called at the end of shared memory

initialization, to give loadable modules a reasonable place to perform
creation of any shared memory areas they need.  This is the logical conclusion
of our previous creation of RequestAddinShmemSpace() and RequestAddinLWLocks().
We don't need an explicit shmem_shutdown_hook, because the existing
on_shmem_exit and on_proc_exit mechanisms serve that need.

Also, adjust SubPostmasterMain so that libraries that got loaded into the
postmaster will be loaded into all child processes, not only regular backends.
This improves consistency with the non-EXEC_BACKEND behavior, and might be
necessary for functionality for some types of add-ons.

diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index f27c69633ad2c8e35634a755cd99e2810aeffa09..22bc5b1f3f1080478876f10c7bbdd50b13c4ee34 100644 (file)
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -37,7 +37,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.568 2009/01/01 17:23:46 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.569 2009/01/03 17:08:38 tgl Exp $
  *
  * NOTES
  *
@@ -3668,6 +3668,14 @@ SubPostmasterMain(int argc, char *argv[])
        /* Read in remaining GUC variables */
        read_nondefault_variables();
 
+       /*
+        * Reload any libraries that were preloaded by the postmaster.  Since
+        * we exec'd this process, those libraries didn't come along with us;
+        * but we should load them into all child processes to be consistent
+        * with the non-EXEC_BACKEND behavior.
+        */
+       process_shared_preload_libraries();
+
        /* Run backend or appropriate child */
        if (strcmp(argv[1], "--forkbackend") == 0)
        {
@@ -3680,21 +3688,15 @@ SubPostmasterMain(int argc, char *argv[])
                 * Need to reinitialize the SSL library in the backend, since the
                 * context structures contain function pointers and cannot be passed
                 * through the parameter file.
+                *
+                * XXX should we do this in all child processes?  For the moment it's
+                * enough to do it in backend children.
                 */
 #ifdef USE_SSL
                if (EnableSSL)
                        secure_initialize();
 #endif
 
-               /*
-                * process any libraries that should be preloaded at postmaster start
-                *
-                * NOTE: we have to re-load the shared_preload_libraries here because
-                * this backend is not fork()ed so we can't inherit any shared
-                * libraries / DLL's from our parent (the postmaster).
-                */
-               process_shared_preload_libraries();
-
                /*
                 * Perform additional initialization and client authentication.
                 *

diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 720f4cd284854080973493f3f7eba25d16a1272f..f85f0a66df208e9e04b269fdb1a7883a523e8a17 100644 (file)
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/storage/ipc/ipci.c,v 1.98 2009/01/01 17:23:47 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/storage/ipc/ipci.c,v 1.99 2009/01/03 17:08:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -34,6 +34,8 @@
 #include "storage/spin.h"
 
 
+shmem_startup_hook_type shmem_startup_hook = NULL;
+
 static Size total_addin_request = 0;
 static bool addin_request_allowed = true;
 
@@ -222,4 +224,10 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
        if (!IsUnderPostmaster)
                ShmemBackendArrayAllocation();
 #endif
+
+       /*
+        * Now give loadable modules a chance to set up their shmem allocations
+        */
+       if (shmem_startup_hook)
+               shmem_startup_hook();
 }

diff --git a/src/include/storage/ipc.h b/src/include/storage/ipc.h
index 8cf326d57c2c6fc65635a661227bbfbc68f5ee94..bcab86d8aa8c1169b23cba74c0dd38dd60a062f4 100644 (file)
--- a/src/include/storage/ipc.h
+++ b/src/include/storage/ipc.h
@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/storage/ipc.h,v 1.76 2009/01/01 17:24:01 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/storage/ipc.h,v 1.77 2009/01/03 17:08:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -19,6 +19,7 @@
 #define IPC_H
 
 typedef void (*pg_on_exit_callback) (int code, Datum arg);
+typedef void (*shmem_startup_hook_type) (void);
 
 /*----------
  * API for handling cleanup that must occur during either ereport(ERROR)
@@ -71,6 +72,8 @@ extern void cancel_shmem_exit(pg_on_exit_callback function, Datum arg);
 extern void on_exit_reset(void);
 
 /* ipci.c */
+extern PGDLLIMPORT shmem_startup_hook_type shmem_startup_hook;
+
 extern void CreateSharedMemoryAndSemaphores(bool makePrivate, int port);
 
 #endif   /* IPC_H */