Another size and performance optimization to readDbPage(). This time we

eliminate some unnecessary local variables.

FossilOrigin-Name: 745bc8decd18d4dc00589474fd3928a3a9f4156d09e05e6f5b8623de6491795a
This commit is contained in:
drh 2017-08-18 22:30:20 +00:00
parent 56520ab848
commit 251866d07c
3 changed files with 15 additions and 17 deletions

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@ -1,5 +1,5 @@
C Size\sand\sperformance\soptimization\sthe\sreadDbPage()\sroutine\sin\sthe\spager.
D 2017-08-18T21:14:50.622
C Another\ssize\sand\sperformance\soptimization\sto\sreadDbPage().\s\sThis\stime\swe\neliminate\ssome\sunnecessary\slocal\svariables.
D 2017-08-18T22:30:20.164
F Makefile.in d9873c9925917cca9990ee24be17eb9613a668012c85a343aef7e5536ae266e8
F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
F Makefile.msc 02b469e9dcd5b7ee63fc1fb05babc174260ee4cfa4e0ef2e48c3c6801567a016
@ -443,7 +443,7 @@ F src/os_setup.h 0dbaea40a7d36bf311613d31342e0b99e2536586
F src/os_unix.c 0a7730f6cb797ba1fd12825e4ea751e1325041410c063c258e30089ca71f9a88
F src/os_win.c 964165b66cde03abc72fe948198b01be608436894732eadb94c8720d2467f223
F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
F src/pager.c fb9a8f40417d6dfbd6b8be91237f2f64d51cc867ab28687420acbc5cab786a3c
F src/pager.c c1dc0609f04a0659519bb2b8ca1440a64b0ad82b6c2afd675f1a50f6c918321a
F src/pager.h f2a99646c5533ffe11afa43e9e0bea74054e4efa
F src/parse.y 52ef3cecd0934e9da4a45b585883a03243ad615d338ad94f44501a05891dcdfa
F src/pcache.c 62835bed959e2914edd26afadfecce29ece0e870
@ -1649,7 +1649,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
P 3075cfa07489eaf13cb9a2760e2391e79dd73181fe1730fae7bdcd6ad66d2a1f
R 73e91e0689b3737aa34e053426722c6a
P ca9e1875c3a893321d70a131fc4ffc76d169ad05e0b48b7006f53b6b467db4be
R 2ae3b6889f1fe566e9272b8874e17865
U drh
Z 58f532a67b173dfa15cad7f44c1bc81c
Z 970c0b65cb119d003a12faf3a1e4e18e

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@ -1 +1 @@
ca9e1875c3a893321d70a131fc4ffc76d169ad05e0b48b7006f53b6b467db4be
745bc8decd18d4dc00589474fd3928a3a9f4156d09e05e6f5b8623de6491795a

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@ -2995,29 +2995,27 @@ end_playback:
*/
static int readDbPage(PgHdr *pPg){
Pager *pPager = pPg->pPager; /* Pager object associated with page pPg */
Pgno pgno = pPg->pgno; /* Page number to read */
int rc = SQLITE_OK; /* Return code */
int pgsz = pPager->pageSize; /* Number of bytes to read */
u32 iFrame = 0; /* Frame of WAL containing pgno */
assert( pPager->eState>=PAGER_READER && !MEMDB );
assert( isOpen(pPager->fd) );
if( pagerUseWal(pPager) ){
rc = sqlite3WalFindFrame(pPager->pWal, pgno, &iFrame);
rc = sqlite3WalFindFrame(pPager->pWal, pPg->pgno, &iFrame);
if( rc ) return rc;
}
if( iFrame ){
rc = sqlite3WalReadFrame(pPager->pWal, iFrame, pgsz, pPg->pData);
rc = sqlite3WalReadFrame(pPager->pWal, iFrame,pPager->pageSize,pPg->pData);
}else{
i64 iOffset = (pgno-1)*(i64)pPager->pageSize;
rc = sqlite3OsRead(pPager->fd, pPg->pData, pgsz, iOffset);
i64 iOffset = (pPg->pgno-1)*(i64)pPager->pageSize;
rc = sqlite3OsRead(pPager->fd, pPg->pData, pPager->pageSize, iOffset);
if( rc==SQLITE_IOERR_SHORT_READ ){
rc = SQLITE_OK;
}
}
if( pgno==1 ){
if( pPg->pgno==1 ){
if( rc ){
/* If the read is unsuccessful, set the dbFileVers[] to something
** that will never be a valid file version. dbFileVers[] is a copy
@ -3037,13 +3035,13 @@ static int readDbPage(PgHdr *pPg){
memcpy(&pPager->dbFileVers, dbFileVers, sizeof(pPager->dbFileVers));
}
}
CODEC1(pPager, pPg->pData, pgno, 3, rc = SQLITE_NOMEM_BKPT);
CODEC1(pPager, pPg->pData, pPg->pgno, 3, rc = SQLITE_NOMEM_BKPT);
PAGER_INCR(sqlite3_pager_readdb_count);
PAGER_INCR(pPager->nRead);
IOTRACE(("PGIN %p %d\n", pPager, pgno));
IOTRACE(("PGIN %p %d\n", pPager, pPg->pgno));
PAGERTRACE(("FETCH %d page %d hash(%08x)\n",
PAGERID(pPager), pgno, pager_pagehash(pPg)));
PAGERID(pPager), pPg->pgno, pager_pagehash(pPg)));
return rc;
}