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Overview
| Comment: | Add code to this branch to emit a log message after each cumulative second that the WRITER lock has been held. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | server-edition |
| Files: | files | file ages | folders |
| SHA3-256: | a726d98122704e1e702cfa7ae61d680497df6a826d98082161e0823e115d40a5 |
| User & Date: | dan 2017-05-22 08:01:58 |
Context
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2017-06-07
| ||
| 15:55 | Add too/tserver.c - the implementation of a simple multi-threaded server designed for interactive testing of concurrency between connections used by different threads of the same process. check-in: 05b4fc43 user: dan tags: server-edition | |
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2017-05-22
| ||
| 08:01 | Add code to this branch to emit a log message after each cumulative second that the WRITER lock has been held. check-in: a726d981 user: dan tags: server-edition | |
|
2017-05-15
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| 19:32 | Avoid writer starvation by adding a RESERVED state to page locks. check-in: 9b7f8024 user: dan tags: server-edition | |
Changes
Changes to src/pager.c.
7546 7547 7548 7549 7550 7551 7552 7553 7554 7555 7556 7557 7558 7559 7560 |
/* Close any rollback journal previously open */
sqlite3OsClose(pPager->jfd);
rc = pagerOpenWal(pPager);
if( rc==SQLITE_OK ){
pPager->journalMode = PAGER_JOURNALMODE_WAL;
pPager->eState = PAGER_OPEN;
sqlite3WalServer(pPager->pWal, pPager->pServer);
}
}else{
*pbOpen = 1;
}
return rc;
}
|
> > |
7546 7547 7548 7549 7550 7551 7552 7553 7554 7555 7556 7557 7558 7559 7560 7561 7562 |
/* Close any rollback journal previously open */
sqlite3OsClose(pPager->jfd);
rc = pagerOpenWal(pPager);
if( rc==SQLITE_OK ){
pPager->journalMode = PAGER_JOURNALMODE_WAL;
pPager->eState = PAGER_OPEN;
#ifdef SQLITE_SERVER_EDITION
sqlite3WalServer(pPager->pWal, pPager->pServer);
#endif
}
}else{
*pbOpen = 1;
}
return rc;
}
|
Changes to src/server.c.
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 ... 450 451 452 453 454 455 456 457 458 459 460 461 462 463 ... 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 |
ino_t st_ino;
};
struct Server {
ServerHMA *pHma; /* Hma file object */
int iClient; /* Client id */
Pager *pPager; /* Associated pager object */
int nAlloc; /* Allocated size of aLock[] array */
int nLock; /* Number of entries in aLock[] */
u32 *aLock; /* Mapped lock file */
};
#define SERVER_WRITE_LOCK 3
#define SERVER_READ_LOCK 2
................................................................................
u32 n = v;
if( (v>>HMA_CLIENT_SLOTS)==p->iClient+1 ){
n = n & ((1 << HMA_CLIENT_SLOTS)-1);
}
n = n & ~(1 << p->iClient);
if( __sync_val_compare_and_swap(pSlot, v, n)==v ) break;
}
}
p->nLock = 0;
#if 1
return posixLock(p->pHma->fd, p->iClient+1, SERVER_READ_LOCK, 0);
#endif
return SQLITE_OK;
}
................................................................................
do{
v = *pSlot;
assert( serverWriteLocker(v)==p->iClient );
n = v & ((1<<HMA_CLIENT_SLOTS)-1);
}while( __sync_val_compare_and_swap(pSlot, v, n)!=v );
}
assert( rc!=SQLITE_OK || sqlite3ServerHasLock(p, pgno, bWrite) );
return rc;
}
int sqlite3ServerHasLock(Server *p, Pgno pgno, int bWrite){
u32 v = *serverPageLockSlot(p, pgno);
if( bWrite ){
return (v>>HMA_CLIENT_SLOTS)==(p->iClient+1);
}
return (v & (1 << p->iClient))!=0;
}
#endif /* ifdef SQLITE_SERVER_EDITION */
|
| > > > > > > > > > > > > > > > > > > |
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ino_t st_ino;
};
struct Server {
ServerHMA *pHma; /* Hma file object */
int iClient; /* Client id */
Pager *pPager; /* Associated pager object */
i64 nUsWrite; /* Cumulative us holding WRITER lock */
i64 iUsWrite; /* Time WRITER lock was taken */
int nAlloc; /* Allocated size of aLock[] array */
int nLock; /* Number of entries in aLock[] */
u32 *aLock; /* Mapped lock file */
};
#define SERVER_WRITE_LOCK 3
#define SERVER_READ_LOCK 2
................................................................................
u32 n = v;
if( (v>>HMA_CLIENT_SLOTS)==p->iClient+1 ){
n = n & ((1 << HMA_CLIENT_SLOTS)-1);
}
n = n & ~(1 << p->iClient);
if( __sync_val_compare_and_swap(pSlot, v, n)==v ) break;
}
if( p->aLock[i]==0 ){
struct timeval t2;
i64 nUs;
gettimeofday(&t2, 0);
nUs = (i64)t2.tv_sec * 1000000 + t2.tv_usec - p->iUsWrite;
p->nUsWrite += nUs;
if( (p->nUsWrite / 1000000)!=((p->nUsWrite + nUs)/1000000) ){
sqlite3_log(SQLITE_WARNING,
"Cumulative WRITER time: %lldms\n", p->nUsWrite/1000
);
}
}
}
p->nLock = 0;
#if 1
return posixLock(p->pHma->fd, p->iClient+1, SERVER_READ_LOCK, 0);
#endif
return SQLITE_OK;
}
................................................................................
do{
v = *pSlot;
assert( serverWriteLocker(v)==p->iClient );
n = v & ((1<<HMA_CLIENT_SLOTS)-1);
}while( __sync_val_compare_and_swap(pSlot, v, n)!=v );
}
if( pgno==0 ){
struct timeval t1;
gettimeofday(&t1, 0);
p->iUsWrite = ((i64)t1.tv_sec * 1000000) + (i64)t1.tv_usec;
}
assert( rc!=SQLITE_OK || sqlite3ServerHasLock(p, pgno, bWrite) );
return rc;
}
int sqlite3ServerHasLock(Server *p, Pgno pgno, int bWrite){
u32 v = *serverPageLockSlot(p, pgno);
if( bWrite ){
return (v>>HMA_CLIENT_SLOTS)==(p->iClient+1);
}
return (v & (1 << p->iClient))!=0;
}
#endif /* ifdef SQLITE_SERVER_EDITION */
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