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Commit863aceb

Browse files
committed
Get rid of PID entries in shmem hash table; there is no longer any need
for them, and making them just wastes time during backend startup/shutdown.Also, remove compile-time MAXBACKENDS limit per long-ago proposal.You can now set MaxBackends as high as your kernel can stand withoutany reconfiguration/recompilation.
1 parent0059c42 commit863aceb

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12 files changed

+213
-316
lines changed

12 files changed

+213
-316
lines changed

‎contrib/userlock/user_locks.c‎

Lines changed: 3 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -73,20 +73,10 @@ user_write_unlock_oid(Oid oid)
7373
}
7474

7575
int
76-
user_unlock_all()
76+
user_unlock_all(void)
7777
{
78-
PROC*proc;
79-
SHMEM_OFFSETlocation;
80-
81-
ShmemPIDLookup(MyProcPid,&location);
82-
if (location==INVALID_OFFSET)
83-
{
84-
elog(NOTICE,"UserUnlockAll: unable to get proc ptr");
85-
return-1;
86-
}
87-
88-
proc= (PROC*)MAKE_PTR(location);
89-
returnLockReleaseAll(USER_LOCKMETHOD,proc, false,InvalidTransactionId);
78+
returnLockReleaseAll(USER_LOCKMETHOD,MyProc, false,
79+
InvalidTransactionId);
9080
}
9181

9282
/* end of file */

‎src/backend/port/darwin/sem.c‎

Lines changed: 51 additions & 39 deletions
Original file line numberDiff line numberDiff line change
@@ -10,10 +10,11 @@
1010
* - this required changing sem_info from containig an array of sem_t to an array of sem_t*
1111
*
1212
* IDENTIFICATION
13-
* $Header: /cvsroot/pgsql/src/backend/port/darwin/Attic/sem.c,v 1.3 2001/03/22 03:59:42 momjian Exp $
13+
* $Header: /cvsroot/pgsql/src/backend/port/darwin/Attic/sem.c,v 1.4 2001/09/07 00:27:29 tgl Exp $
1414
*
1515
*-------------------------------------------------------------------------
1616
*/
17+
#include"postgres.h"
1718

1819
#include<errno.h>
1920
#include<semaphore.h>
@@ -22,13 +23,13 @@
2223
#include<unistd.h>
2324
#include<fcntl.h>
2425
#include<sys/mman.h>
25-
#include"postgres.h"
26+
27+
#include"miscadmin.h"
2628
#include"storage/ipc.h"
2729
#include"storage/proc.h"
2830
#include"port/darwin/sem.h"
2931

3032
#defineSEMMAXIPC_NMAXSEM
31-
#defineSETMAX ((MAXBACKENDS + SEMMAX - 1) / SEMMAX)
3233
#defineOPMAX8
3334

3435
#defineMODE0700
@@ -41,19 +42,23 @@ struct pending_ops
4142
intidx;/* index of first free array member */
4243
};
4344

45+
structsem_set_info
46+
{
47+
key_tkey;
48+
intnsems;
49+
sem_t*sem[SEMMAX];/* array of POSIX semaphores */
50+
structsemsemV[SEMMAX];/* array of System V semaphore
51+
* structures */
52+
structpending_opspendingOps[SEMMAX];/* array of pending
53+
* operations */
54+
};
55+
4456
structsem_info
4557
{
4658
sem_t*sem;
47-
struct
48-
{
49-
key_tkey;
50-
intnsems;
51-
sem_t*sem[SEMMAX];/* array of POSIX semaphores */
52-
structsemsemV[SEMMAX];/* array of System V semaphore
53-
* structures */
54-
structpending_opspendingOps[SEMMAX];/* array of pending
55-
* operations */
56-
}set[SETMAX];
59+
intnsets;
60+
/* there are actually nsets of these: */
61+
structsem_set_infoset[1];/* VARIABLE LENGTH ARRAY */
5762
};
5863

5964
staticstructsem_info*SemInfo= (structsem_info*)-1;
@@ -66,7 +71,7 @@ semctl(int semid, int semnum, int cmd, /* ... */ union semun arg)
6671

6772
sem_wait(SemInfo->sem);
6873

69-
if (semid<0||semid >=SETMAX||
74+
if (semid<0||semid >=SemInfo->nsets||
7075
semnum<0||semnum >=SemInfo->set[semid].nsems)
7176
{
7277
sem_post(SemInfo->sem);
@@ -132,8 +137,10 @@ semget(key_t key, int nsems, int semflg)
132137
{
133138
intfd,
134139
semid,
135-
semnum/* , semnum1 */ ;
140+
semnum,
141+
nsets;
136142
intexist=0;
143+
Sizesem_info_size;
137144
charsemname[64];
138145

139146
if (nsems<0||nsems>SEMMAX)
@@ -163,44 +170,46 @@ semget(key_t key, int nsems, int semflg)
163170
returnfd;
164171
shm_unlink(SHM_INFO_NAME);
165172
/* The size may only be set once. Ignore errors. */
166-
ftruncate(fd,sizeof(structsem_info));
167-
SemInfo=mmap(NULL,sizeof(structsem_info),
173+
nsets=PROC_SEM_MAP_ENTRIES(MaxBackends);
174+
sem_info_size=sizeof(structsem_info)+ (nsets-1)*sizeof(structsem_set_info);
175+
ftruncate(fd,sem_info_size);
176+
SemInfo=mmap(NULL,sem_info_size,
168177
PROT_READ |PROT_WRITE,MAP_SHARED,fd,0);
169178
if (SemInfo==MAP_FAILED)
170179
return-1;
171180
if (!exist)
172181
{
182+
/* initialize shared memory */
183+
memset(SemInfo,0,sem_info_size);
184+
SemInfo->nsets=nsets;
185+
for (semid=0;semid<nsets;semid++)
186+
SemInfo->set[semid].key=-1;
173187
/* create semaphore for locking */
174188
sprintf(semname,"%s-map",SEM_NAME);
175189
#ifdefDEBUG_IPC
176190
fprintf(stderr,"darwin creating sem %s to cover shared mem.\n",semname);
177191
#endif
178192
SemInfo->sem=sem_open(semname,O_CREAT,semflg&0777,1);
179193
sem_unlink(semname);
180-
sem_wait(SemInfo->sem);
181-
/* initilize shared memory */
182-
memset(SemInfo->set,0,sizeof(SemInfo->set));
183-
for (semid=0;semid<SETMAX;semid++)
184-
SemInfo->set[semid].key=-1;
185-
sem_post(SemInfo->sem);
186194
}
187195
}
188196

189197
sem_wait(SemInfo->sem);
198+
nsets=SemInfo->nsets;
190199

191200
if (key!=IPC_PRIVATE)
192201
{
193202
/* search existing element */
194203
semid=0;
195-
while (semid<SETMAX&&SemInfo->set[semid].key!=key)
204+
while (semid<nsets&&SemInfo->set[semid].key!=key)
196205
semid++;
197-
if (!(semflg&IPC_CREAT)&&semid >=SETMAX)
206+
if (!(semflg&IPC_CREAT)&&semid >=nsets)
198207
{
199208
sem_post(SemInfo->sem);
200209
errno=ENOENT;
201210
return-1;
202211
}
203-
elseif (semid<SETMAX)
212+
elseif (semid<nsets)
204213
{
205214
if (semflg&IPC_CREAT&&semflg&IPC_EXCL)
206215
{
@@ -228,12 +237,12 @@ semget(key_t key, int nsems, int semflg)
228237

229238
/* search first free element */
230239
semid=0;
231-
while (semid<SETMAX&&SemInfo->set[semid].key!=-1)
240+
while (semid<nsets&&SemInfo->set[semid].key!=-1)
232241
semid++;
233-
if (semid >=SETMAX)
242+
if (semid >=nsets)
234243
{
235244
#ifdefDEBUG_IPC
236-
fprintf(stderr,"darwin semget failed because all keys were -1 up to SETMAX\n");
245+
fprintf(stderr,"darwin semget failed because all keys were -1\n");
237246
#endif
238247
sem_post(SemInfo->sem);
239248
errno=ENOSPC;
@@ -249,15 +258,18 @@ semget(key_t key, int nsems, int semflg)
249258
SemInfo->set[semid].sem[semnum]=sem_open(semname,O_CREAT,semflg&0777,0);
250259
sem_unlink(semname);
251260

252-
/* Currently sem_init always returns -1.
253-
if( sem_init( &SemInfo->set[semid].sem[semnum], 1, 0 ) == -1 ){
254-
for( semnum1 = 0; semnum1 < semnum; semnum1++ ) {
255-
sem_close( SemInfo->set[semid].sem[semnum1] );
256-
}
257-
sem_post( SemInfo->sem );
258-
return -1;
259-
}
260-
*/
261+
/* Currently sem_init always returns -1. */
262+
#ifdefNOT_USED
263+
if(sem_init(&SemInfo->set[semid].sem[semnum],1,0 )==-1 ){
264+
intsemnum1;
265+
266+
for(semnum1=0;semnum1<semnum;semnum1++ ) {
267+
sem_close(SemInfo->set[semid].sem[semnum1] );
268+
}
269+
sem_post(SemInfo->sem );
270+
return-1;
271+
}
272+
#endif
261273
}
262274

263275
SemInfo->set[semid].key=key;
@@ -279,7 +291,7 @@ semop(int semid, struct sembuf * sops, size_t nsops)
279291

280292
sem_wait(SemInfo->sem);
281293

282-
if (semid<0||semid >=SETMAX)
294+
if (semid<0||semid >=SemInfo->nsets)
283295
{
284296
sem_post(SemInfo->sem);
285297
errno=EINVAL;

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