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Final rearrangement of main postgresql child process (ie.
BackendFork/SSDataBase/pgstat) startup, to allow fork/exec calls to closely mimic (the soon to be provided) Win32 CreateProcess equivalent calls. Claudio Natoli
1 parent 06288d4 commit 488f278

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6 files changed

+254
-160
lines changed

6 files changed

+254
-160
lines changed

‎src/backend/bootstrap/bootstrap.c

Lines changed: 16 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/bootstrap/bootstrap.c,v 1.172 2003/12/25 03:52:50 momjian Exp $
11+
* $PostgreSQL: pgsql/src/backend/bootstrap/bootstrap.c,v 1.173 2004/01/06 23:15:22 momjian Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -51,7 +51,7 @@
5151
#ifdef EXEC_BACKEND
5252
typedef struct Port Port;
5353
extern void SSDataBaseInit(int);
54-
extern void read_backend_variables(pid_t, Port*);
54+
extern void read_backend_variables(unsigned long, Port*);
5555
#endif
5656

5757
extern int Int_yyparse(void);
@@ -231,6 +231,9 @@ BootstrapMain(int argc, char *argv[])
231231
int flag;
232232
int xlogop = BS_XLOG_NOP;
233233
char *potential_DataDir = NULL;
234+
#ifdef EXEC_BACKEND
235+
unsigned long backendID = 0;
236+
#endif
234237

235238
/*
236239
* initialize globals
@@ -291,10 +294,15 @@ BootstrapMain(int argc, char *argv[])
291294
break;
292295
case 'p':
293296
#ifdef EXEC_BACKEND
294-
IsUnderPostmaster = true;
297+
{
298+
char buf[MAXPGPATH];
299+
IsUnderPostmaster = true;
300+
sscanf(optarg,"%lu,%s",&backendID,buf);
301+
dbname = strdup(buf);
302+
}
295303
#endif
296304
dbname = strdup(optarg);
297-
break;
305+
break;
298306
case 'B':
299307
SetConfigOption("shared_buffers", optarg, PGC_POSTMASTER, PGC_S_ARGV);
300308
break;
@@ -363,7 +371,7 @@ BootstrapMain(int argc, char *argv[])
363371
{
364372
#ifdef EXEC_BACKEND
365373
read_nondefault_variables();
366-
read_backend_variables(getpid(),NULL);
374+
read_backend_variables(backendID,NULL);
367375

368376
SSDataBaseInit(xlogop);
369377
#endif
@@ -431,11 +439,11 @@ BootstrapMain(int argc, char *argv[])
431439
switch (xlogop)
432440
{
433441
case BS_XLOG_BGWRITER:
434-
InitDummyProcess(DUMMY_PROC_BGWRITER);
442+
InitDummyProcess(DUMMY_PROC_BGWRITER);
435443
break;
436-
444+
437445
default:
438-
InitDummyProcess(DUMMY_PROC_DEFAULT);
446+
InitDummyProcess(DUMMY_PROC_DEFAULT);
439447
break;
440448
}
441449
}

‎src/backend/main/main.c

Lines changed: 14 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -13,7 +13,7 @@
1313
*
1414
*
1515
* IDENTIFICATION
16-
* $PostgreSQL: pgsql/src/backend/main/main.c,v 1.69 2003/12/25 03:52:50 momjian Exp $
16+
* $PostgreSQL: pgsql/src/backend/main/main.c,v 1.70 2004/01/06 23:15:22 momjian Exp $
1717
*
1818
*-------------------------------------------------------------------------
1919
*/
@@ -203,9 +203,9 @@ main(int argc, char *argv[])
203203

204204
/*
205205
* Now dispatch to one of PostmasterMain, PostgresMain, GucInfoMain,
206-
* pgstat_main, pgstat_mainChild or BootstrapMain depending on the
207-
* program name (and possibly first argument) we were called with.
208-
* The lack of consistency here is historical.
206+
* SubPostmasterMain, pgstat_main, pgstat_mainChild or BootstrapMain
207+
* depending on the program name (and possibly first argument) we
208+
* were called with. The lack of consistency here is historical.
209209
*/
210210
len = strlen(new_argv[0]);
211211

@@ -223,6 +223,16 @@ main(int argc, char *argv[])
223223
exit(BootstrapMain(argc - 1, new_argv + 1));
224224

225225
#ifdef EXEC_BACKEND
226+
/*
227+
* If the first argument is "-forkexec", then invoke SubPostmasterMain. Note
228+
* we remove "-forkexec" from the arguments passed on to SubPostmasterMain.
229+
*/
230+
if (argc > 1 && strcmp(new_argv[1], "-forkexec") == 0)
231+
{
232+
SubPostmasterMain(argc - 2, new_argv + 2);
233+
exit(0);
234+
}
235+
226236
/*
227237
* If the first argument is "-statBuf", then invoke pgstat_main. Note
228238
* we remove "-statBuf" from the arguments passed on to pgstat_main.

‎src/backend/postmaster/pgstat.c

Lines changed: 38 additions & 32 deletions
Original file line numberDiff line numberDiff line change
@@ -13,7 +13,7 @@
1313
*
1414
* Copyright (c) 2001-2003, PostgreSQL Global Development Group
1515
*
16-
* $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.50 2003/12/25 03:52:51 momjian Exp $
16+
* $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.51 2004/01/06 23:15:22 momjian Exp $
1717
* ----------
1818
*/
1919
#include "postgres.h"
@@ -107,7 +107,7 @@ static char pgStat_fname[MAXPGPATH];
107107
* ----------
108108
*/
109109
#ifdef EXEC_BACKEND
110-
static void pgstat_exec(STATS_PROCESS_TYPE procType);
110+
static pid_t pgstat_forkexec(STATS_PROCESS_TYPE procType);
111111
static void pgstat_parseArgs(PGSTAT_FORK_ARGS);
112112
#endif
113113
NON_EXEC_STATIC void pgstat_main(PGSTAT_FORK_ARGS);
@@ -337,15 +337,16 @@ pgstat_init(void)
337337
#ifdef EXEC_BACKEND
338338

339339
/* ----------
340-
* pgstat_exec() -
340+
* pgstat_forkexec() -
341341
*
342-
* Used to format up the arglist for, and exec, statistics
342+
* Used to format up the arglist for, then fork and exec, statistics
343343
* (buffer and collector) processes
344344
*
345345
*/
346-
static void
347-
pgstat_exec(STATS_PROCESS_TYPE procType)
346+
static pid_t
347+
pgstat_forkexec(STATS_PROCESS_TYPE procType)
348348
{
349+
pid_t pid;
349350
char *av[11];
350351
int ac = 0, bufc = 0, i;
351352
char pgstatBuf[8][MAXPGPATH];
@@ -387,9 +388,12 @@ pgstat_exec(STATS_PROCESS_TYPE procType)
387388
av[ac++] = NULL;
388389
Assert(ac <= lengthof(av));
389390

390-
if (execv(pg_pathname,av) == -1)
391+
/* Fire off execv in child */
392+
if ((pid = fork()) == 0 && (execv(pg_pathname,av) == -1))
391393
/* FIXME: [fork/exec] suggestions for what to do here? Can't call elog... */
392-
Assert(false);
394+
abort();
395+
396+
return pid; /* Parent returns pid */
393397
}
394398

395399

@@ -479,7 +483,11 @@ pgstat_start(void)
479483
beos_before_backend_startup();
480484
#endif
481485

486+
#ifdef EXEC_BACKEND
487+
switch ((pgStatSock = (int) pgstat_forkexec(STAT_PROC_BUFFER)))
488+
#else
482489
switch ((pgStatPid = (int) fork()))
490+
#endif
483491
{
484492
case -1:
485493
#ifdef __BEOS__
@@ -490,32 +498,27 @@ pgstat_start(void)
490498
(errmsg("could not fork statistics buffer: %m")));
491499
return;
492500

501+
#ifndef EXEC_BACKEND
493502
case 0:
503+
/* in postmaster child ... */
504+
#ifdef __BEOS__
505+
/* Specific beos actions after backend startup */
506+
beos_backend_startup();
507+
#endif
508+
/* Close the postmaster's sockets, except for pgstat link */
509+
ClosePostmasterPorts(false);
510+
511+
/* Drop our connection to postmaster's shared memory, as well */
512+
PGSharedMemoryDetach();
513+
514+
pgstat_main();
494515
break;
516+
#endif
495517

496518
default:
497519
pgstat_is_running = true;
498520
return;
499521
}
500-
501-
/* in postmaster child ... */
502-
503-
#ifdef __BEOS__
504-
/* Specific beos actions after backend startup */
505-
beos_backend_startup();
506-
#endif
507-
508-
/* Close the postmaster's sockets, except for pgstat link */
509-
ClosePostmasterPorts(false);
510-
511-
/* Drop our connection to postmaster's shared memory, as well */
512-
PGSharedMemoryDetach();
513-
514-
#ifdef EXEC_BACKEND
515-
pgstat_exec(STAT_PROC_BUFFER);
516-
#else
517-
pgstat_main();
518-
#endif
519522
}
520523

521524

@@ -1385,28 +1388,31 @@ pgstat_main(PGSTAT_FORK_ARGS)
13851388
exit(1);
13861389
}
13871390

1391+
#ifdef EXEC_BACKEND
1392+
/* child becomes collector process */
1393+
switch (pgstat_forkexec(STAT_PROC_COLLECTOR))
1394+
#else
13881395
switch (fork())
1396+
#endif
13891397
{
13901398
case -1:
13911399
ereport(LOG,
13921400
(errmsg("could not fork statistics collector: %m")));
13931401
exit(1);
13941402

1403+
#ifndef EXEC_BACKEND
13951404
case 0:
13961405
/* child becomes collector process */
1397-
#ifdef EXEC_BACKEND
1398-
pgstat_exec(STAT_PROC_COLLECTOR);
1399-
#else
14001406
pgstat_mainChild();
1407+
break;
14011408
#endif
1402-
exit(0);
14031409

14041410
default:
14051411
/* parent becomes buffer process */
14061412
closesocket(pgStatPipe[0]);
14071413
pgstat_recvbuffer();
1408-
exit(0);
14091414
}
1415+
exit(0);
14101416
}
14111417

14121418

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