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Refactor EXEC_BACKEND code so that postmaster child processes reattach

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to shared memory as soon as possible, ie, right after read_backend_variables.
The effective difference from the original code is that this happens
before instead of after read_nondefault_variables(), which loads GUC
information and is apparently capable of expanding the backend's memory
allocation more than you'd think it should.  This should fix the
failure-to-attach-to-shared-memory reports we've been seeing on Windows.
Also clean up a few bits of unnecessarily grotty EXEC_BACKEND code.
This commit is contained in:
Tom Lane
2004-12-29 21:36:09 +00:00
parent e14018dc5e
commit eee5abce46
7 changed files with 179 additions and 124 deletions
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60
src/backend/postmaster/postmaster.c
View File

@@ -37,7 +37,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.440 2004/11/17 08:30:09 neilc Exp $
* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.441 2004/12/29 21:36:03 tgl Exp $
*
* NOTES
*
@@ -1584,10 +1584,8 @@ processCancelRequest(Port *port, void *pkt)
int backendPID;
long cancelAuthCode;
Backend *bp;
#ifndef EXEC_BACKEND
Dlelem *curr;
#else
int i;
#endif
@@ -3152,10 +3150,31 @@ SubPostmasterMain(int argc, char *argv[])
MyProcPid = getpid(); /* reset MyProcPid */
/* Read in file-based context */
/* In EXEC_BACKEND case we will not have inherited these settings */
IsPostmasterEnvironment = true;
whereToSendOutput = None;
/* Setup essential subsystems (to ensure elog() behaves sanely) */
MemoryContextInit();
InitializeGUCOptions();
/* Read in the variables file */
memset(&port, 0, sizeof(Port));
read_backend_variables(argv[2], &port);
/* Check we got appropriate args */
if (argc < 3)
elog(FATAL, "invalid subpostmaster invocation");
/*
* If appropriate, physically re-attach to shared memory segment.
* We want to do this before going any further to ensure that we
* can attach at the same address the postmaster used.
*/
if (strcmp(argv[1], "-forkbackend") == 0 ||
strcmp(argv[1], "-forkboot") == 0)
PGSharedMemoryReAttach();
/*
* Start our win32 signal implementation. This has to be done
* after we read the backend variables, because we need to pick
@@ -3166,19 +3185,9 @@ SubPostmasterMain(int argc, char *argv[])
#endif
/* In EXEC_BACKEND case we will not have inherited these settings */
IsPostmasterEnvironment = true;
whereToSendOutput = None;
pqinitmask();
PG_SETMASK(&BlockSig);
/* Setup essential subsystems */
MemoryContextInit();
InitializeGUCOptions();
/* Check we got appropriate args */
if (argc < 3)
elog(FATAL, "invalid subpostmaster invocation");
/* Read in remaining GUC variables */
read_nondefault_variables();
@@ -3187,7 +3196,7 @@ SubPostmasterMain(int argc, char *argv[])
{
/* BackendRun will close sockets */
/* Attach process to shared segments */
/* Attach process to shared data structures */
CreateSharedMemoryAndSemaphores(false, MaxBackends, 0);
#ifdef USE_SSL
@@ -3208,7 +3217,7 @@ SubPostmasterMain(int argc, char *argv[])
/* Close the postmaster's sockets */
ClosePostmasterPorts(false);
/* Attach process to shared segments */
/* Attach process to shared data structures */
CreateSharedMemoryAndSemaphores(false, MaxBackends, 0);
BootstrapMain(argc - 2, argv + 2);
@@ -3259,6 +3268,7 @@ SubPostmasterMain(int argc, char *argv[])
return 1; /* shouldn't get here */
}
#endif /* EXEC_BACKEND */
@@ -3767,10 +3777,11 @@ read_inheritable_socket(SOCKET *dest, InheritableSocket *src)
static void
read_backend_variables(char *id, Port *port)
{
BackendParameters param;
#ifndef WIN32
/* Non-win32 implementation reads from file */
FILE *fp;
BackendParameters param;
/* Open file */
fp = AllocateFile(id, PG_BINARY_R);
@@ -3796,25 +3807,23 @@ read_backend_variables(char *id, Port *port)
id, strerror(errno));
exit(1);
}
restore_backend_variables(&param, port);
#else
/* Win32 version uses mapped file */
HANDLE paramHandle;
BackendParameters *param;
BackendParameters *paramp;
paramHandle = (HANDLE)atol(id);
param = MapViewOfFile(paramHandle, FILE_MAP_READ, 0, 0, 0);
if (!param)
paramp = MapViewOfFile(paramHandle, FILE_MAP_READ, 0, 0, 0);
if (!paramp)
{
write_stderr("could not map view of backend variables: error code %d\n",
(int) GetLastError());
exit(1);
}
restore_backend_variables(param, port);
memcpy(&param, paramp, sizeof(BackendParameters));
if (!UnmapViewOfFile(param))
if (!UnmapViewOfFile(paramp))
{
write_stderr("could not unmap view of backend variables: error code %d\n",
(int) GetLastError());
@@ -3828,6 +3837,8 @@ read_backend_variables(char *id, Port *port)
exit(1);
}
#endif
restore_backend_variables(&param, port);
}
/* Restore critical backend variables from the BackendParameters struct */
@@ -3930,6 +3941,7 @@ ShmemBackendArrayRemove(pid_t pid)
(errmsg_internal("could not find backend entry with pid %d",
(int) pid)));
}
#endif /* EXEC_BACKEND */