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Keep track of the last active slot in the shared ProcState array, so
that search loops only have to scan that far and not through all maxBackends entries. This eliminates a performance penalty for setting maxBackends much higher than the average number of active backends. Also, eliminate no-longer-used 'backend tag' concept. Remove setting of environment variables at backend start (except for CYR_RECODE), since none of them are being examined by the backend any longer.
1 parent c48025e commit ebb0a20

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10 files changed

+151
-233
lines changed

10 files changed

+151
-233
lines changed

‎src/backend/commands/dbcommands.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/commands/dbcommands.c,v 1.65 2000/11/08 23:24:24 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/commands/dbcommands.c,v 1.66 2000/11/12 20:51:50 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -225,7 +225,7 @@ dropdb(const char *dbname)
225225
/*
226226
* Check for active backends in the target database.
227227
*/
228-
if (DatabaseHasActiveBackends(db_id))
228+
if (DatabaseHasActiveBackends(db_id, false))
229229
{
230230
heap_close(pgdbrel, AccessExclusiveLock);
231231
elog(ERROR, "DROP DATABASE: database \"%s\" is being accessed by other users", dbname);

‎src/backend/postmaster/postmaster.c

Lines changed: 69 additions & 115 deletions
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
1111
*
1212
*
1313
* IDENTIFICATION
14-
* $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.181 2000/11/09 11:25:59 vadim Exp $
14+
* $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.182 2000/11/12 20:51:51 tgl Exp $
1515
*
1616
* NOTES
1717
*
@@ -107,55 +107,45 @@ typedef struct bkend
107107
Port *MyBackendPort = NULL;
108108

109109
/* list of active backends. For garbage collection only now. */
110-
111110
static Dllist *BackendList;
112111

113112
/* list of ports associated with still open, but incomplete connections */
114113
static Dllist *PortList;
115114

115+
/* The socket number we are listening for connections on */
116116
int PostPortName;
117117

118-
/*
119-
* This is a boolean indicating that there is at least one backend that
120-
* is accessing the current shared memory and semaphores. Between the
121-
* time that we start up, or throw away shared memory segments and start
122-
* over, and the time we generate the next backend (because we received a
123-
* connection request), it is false. Other times, it is true.
124-
*/
118+
/*
119+
* This is a sequence number that indicates how many times we've had to
120+
* throw away the shared memory and start over because we doubted its
121+
* integrity. It starts off at zero and is incremented every time we
122+
* start over. We use this to ensure that we use a new IPC shared memory
123+
* key for the new shared memory segment in case the old segment isn't
124+
* entirely gone yet.
125+
*
126+
* The sequence actually cycles back to 0 after 9, so pathologically there
127+
* could be an IPC failure if 10 sets of backends are all stuck and won't
128+
* release IPC resources.
129+
*/
125130
static short shmem_seq = 0;
126131

127-
/*
128-
* This is a sequence number that indicates how many times we've had to
129-
* throw away the shared memory and start over because we doubted its
130-
* integrity. It starts off at zero and is incremented every time we
131-
* start over. We use this to ensure that we use a new IPC shared memory
132-
* key for the new shared memory segment in case the old segment isn't
133-
* entirely gone yet.
134-
*
135-
* The sequence actually cycles back to 0 after 9, so pathologically there
136-
* could be an IPC failure if 10 sets of backends are all stuck and won't
137-
* release IPC resources.
138-
*/
139-
132+
/*
133+
* This is the base IPC shared memory key. Other keys are generated by
134+
* adding to this.
135+
*/
140136
static IpcMemoryKey ipc_key;
141137

142-
/*
143-
* This is the base IPC shared memory key. Other keys are generated by
144-
* adding to this.
145-
*/
146-
138+
/*
139+
* MaxBackends is the actual limit on the number of backends we will
140+
* start. The default is established by configure, but it can be
141+
* readjusted from 1..MAXBACKENDS with the postmaster -N switch. Note
142+
* that a larger MaxBackends value will increase the size of the shared
143+
* memory area as well as cause the postmaster to grab more kernel
144+
* semaphores, even if you never actually use that many backends.
145+
*/
147146
int MaxBackends = DEF_MAXBACKENDS;
148147

149-
/*
150-
* MaxBackends is the actual limit on the number of backends we will
151-
* start. The default is established by configure, but it can be
152-
* readjusted from 1..MAXBACKENDS with the postmaster -N switch. Note
153-
* that a larger MaxBackends value will increase the size of the shared
154-
* memory area as well as cause the postmaster to grab more kernel
155-
* semaphores, even if you never actually use that many backends.
156-
*/
157148

158-
static int NextBackendTag = INT_MAX; /* XXX why count down not up? */
159149
static char *progname = (char *) NULL;
160150
static char **real_argv;
161151
static int real_argc;
@@ -587,6 +577,22 @@ PostmasterMain(int argc, char *argv[])
587577
exit(1);
588578
}
589579

580+
if (DebugLvl > 2)
581+
{
582+
extern char **environ;
583+
char **p;
584+
585+
fprintf(stderr, "%s: PostmasterMain: initial environ dump:\n",
586+
progname);
587+
fprintf(stderr, "-----------------------------------------\n");
588+
for (p = environ; *p; ++p)
589+
fprintf(stderr, "\t%s\n", *p);
590+
fprintf(stderr, "-----------------------------------------\n");
591+
}
592+
593+
/*
594+
* Establish input sockets.
595+
*/
590596
#ifdef USE_SSL
591597
if (EnableSSL && !NetServer)
592598
{
@@ -600,7 +606,8 @@ PostmasterMain(int argc, char *argv[])
600606

601607
if (NetServer)
602608
{
603-
status = StreamServerPort(AF_INET, (unsigned short)PostPortName, &ServerSock_INET);
609+
status = StreamServerPort(AF_INET, (unsigned short) PostPortName,
610+
&ServerSock_INET);
604611
if (status != STATUS_OK)
605612
{
606613
fprintf(stderr, "%s: cannot create INET stream port\n",
@@ -610,18 +617,20 @@ PostmasterMain(int argc, char *argv[])
610617
}
611618

612619
#ifdef HAVE_UNIX_SOCKETS
613-
status = StreamServerPort(AF_UNIX, (unsigned short)PostPortName, &ServerSock_UNIX);
620+
status = StreamServerPort(AF_UNIX, (unsigned short) PostPortName,
621+
&ServerSock_UNIX);
614622
if (status != STATUS_OK)
615623
{
616624
fprintf(stderr, "%s: cannot create UNIX stream port\n",
617625
progname);
618626
ExitPostmaster(1);
619627
}
620628
#endif
629+
621630
/* set up shared memory and semaphores */
622631
reset_shared(PostPortName);
623632

624-
/* Init XLOG pathes */
633+
/* Init XLOG paths */
625634
snprintf(XLogDir, MAXPGPATH, "%s/pg_xlog", DataDir);
626635
snprintf(ControlFilePath, MAXPGPATH, "%s/global/pg_control", DataDir);
627636

@@ -1706,43 +1715,7 @@ static int
17061715
BackendStartup(Port *port)
17071716
{
17081717
Backend *bn; /* for backend cleanup */
1709-
int pid,
1710-
i;
1711-
1712-
#ifdef CYR_RECODE
1713-
#define NR_ENVIRONMENT_VBL 5
1714-
char ChTable[80];
1715-
1716-
#else
1717-
#define NR_ENVIRONMENT_VBL 4
1718-
#endif
1719-
1720-
static char envEntry[NR_ENVIRONMENT_VBL][2 * ARGV_SIZE];
1721-
1722-
for (i = 0; i < NR_ENVIRONMENT_VBL; ++i)
1723-
MemSet(envEntry[i], 0, 2 * ARGV_SIZE);
1724-
1725-
/*
1726-
* Set up the necessary environment variables for the backend This
1727-
* should really be some sort of message....
1728-
*/
1729-
sprintf(envEntry[0], "POSTPORT=%d", PostPortName);
1730-
putenv(envEntry[0]);
1731-
sprintf(envEntry[1], "POSTID=%d", NextBackendTag);
1732-
putenv(envEntry[1]);
1733-
sprintf(envEntry[2], "PGDATA=%s", DataDir);
1734-
putenv(envEntry[2]);
1735-
sprintf(envEntry[3], "IPC_KEY=%d", ipc_key);
1736-
putenv(envEntry[3]);
1737-
1738-
#ifdef CYR_RECODE
1739-
GetCharSetByHost(ChTable, port->raddr.in.sin_addr.s_addr, DataDir);
1740-
if (*ChTable != '\0')
1741-
{
1742-
sprintf(envEntry[4], "PG_RECODETABLE=%s", ChTable);
1743-
putenv(envEntry[4]);
1744-
}
1745-
#endif
1718+
int pid;
17461719

17471720
/*
17481721
* Compute the cancel key that will be assigned to this backend. The
@@ -1751,19 +1724,6 @@ BackendStartup(Port *port)
17511724
*/
17521725
MyCancelKey = PostmasterRandom();
17531726

1754-
if (DebugLvl > 2)
1755-
{
1756-
char **p;
1757-
extern char **environ;
1758-
1759-
fprintf(stderr, "%s: BackendStartup: environ dump:\n",
1760-
progname);
1761-
fprintf(stderr, "-----------------------------------------\n");
1762-
for (p = environ; *p; ++p)
1763-
fprintf(stderr, "\t%s\n", *p);
1764-
fprintf(stderr, "-----------------------------------------\n");
1765-
}
1766-
17671727
/*
17681728
* Flush stdio channels just before fork, to avoid double-output
17691729
* problems. Ideally we'd use fflush(NULL) here, but there are still a
@@ -1779,12 +1739,30 @@ BackendStartup(Port *port)
17791739
/* Specific beos actions before backend startup */
17801740
beos_before_backend_startup();
17811741
#endif
1742+
17821743
if ((pid = fork()) == 0)
17831744
{ /* child */
17841745
#ifdef __BEOS__
1785-
/* Specific beos backend stratup actions */
1746+
/* Specific beos backend startup actions */
17861747
beos_backend_startup();
17871748
#endif
1749+
1750+
#ifdef CYR_RECODE
1751+
{
1752+
/* Save charset for this host while we still have client addr */
1753+
char ChTable[80];
1754+
static char cyrEnvironment[100];
1755+
1756+
GetCharSetByHost(ChTable, port->raddr.in.sin_addr.s_addr, DataDir);
1757+
if (*ChTable != '\0')
1758+
{
1759+
snprintf(cyrEnvironment, sizeof(cyrEnvironment),
1760+
"PG_RECODETABLE=%s", ChTable);
1761+
putenv(cyrEnvironment);
1762+
}
1763+
}
1764+
#endif
1765+
17881766
if (DoBackend(port))
17891767
{
17901768
fprintf(stderr, "%s child[%d]: BackendStartup: backend startup failed\n",
@@ -1799,7 +1777,7 @@ BackendStartup(Port *port)
17991777
if (pid < 0)
18001778
{
18011779
#ifdef __BEOS__
1802-
/* Specific beos backend stratup actions */
1780+
/* Specific beos backend startup actions */
18031781
beos_backend_startup_failed();
18041782
#endif
18051783
fprintf(stderr, "%s: BackendStartup: fork failed: %s\n",
@@ -1812,14 +1790,6 @@ BackendStartup(Port *port)
18121790
progname, pid, port->user, port->database,
18131791
port->sock);
18141792

1815-
/* Generate a new backend tag for every backend we start */
1816-
1817-
/*
1818-
* XXX theoretically this could wrap around, if you have the patience
1819-
* to start 2^31 backends ...
1820-
*/
1821-
NextBackendTag -= 1;
1822-
18231793
/*
18241794
* Everything's been successful, it's safe to add this backend to our
18251795
* list of backends.
@@ -2179,21 +2149,7 @@ static pid_t
21792149
SSDataBase(int xlop)
21802150
{
21812151
pid_t pid;
2182-
int i;
21832152
Backend *bn;
2184-
static char ssEntry[4][2 * ARGV_SIZE];
2185-
2186-
for (i = 0; i < 4; ++i)
2187-
MemSet(ssEntry[i], 0, 2 * ARGV_SIZE);
2188-
2189-
sprintf(ssEntry[0], "POSTPORT=%d", PostPortName);
2190-
putenv(ssEntry[0]);
2191-
sprintf(ssEntry[1], "POSTID=%d", NextBackendTag);
2192-
putenv(ssEntry[1]);
2193-
sprintf(ssEntry[2], "PGDATA=%s", DataDir);
2194-
putenv(ssEntry[2]);
2195-
sprintf(ssEntry[3], "IPC_KEY=%d", ipc_key);
2196-
putenv(ssEntry[3]);
21972153

21982154
fflush(stdout);
21992155
fflush(stderr);
@@ -2258,8 +2214,6 @@ SSDataBase(int xlop)
22582214
ExitPostmaster(1);
22592215
}
22602216

2261-
NextBackendTag -= 1;
2262-
22632217
if (xlop != BS_XLOG_CHECKPOINT)
22642218
return(pid);
22652219

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