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Change getAndInitPage() (btree.c) to use only PagerAcquire(), not PagerLookup() and PagerAcquire(). (CVS 6916)

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FossilOrigin-Name: 0b41dfc066b60ccabbf1a9ab4db41ebcb73a2799
This commit is contained in:
danielk1977
2009-07-21 19:25:24 +00:00
parent fe3313f9b1
commit 89bc4bc645
8 changed files with 106 additions and 109 deletions
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61
src/btree.c
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@@ -9,7 +9,7 @@
** May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.696 2009/07/21 19:02:21 drh Exp $
** $Id: btree.c,v 1.697 2009/07/21 19:25:24 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
@@ -1540,9 +1540,12 @@ static Pgno pagerPagecount(BtShared *pBt){
}
/*
** Get a page from the pager and initialize it. This routine
** is just a convenience wrapper around separate calls to
** btreeGetPage() and btreeInitPage().
** Get a page from the pager and initialize it. This routine is just a
** convenience wrapper around separate calls to btreeGetPage() and
** btreeInitPage().
**
** If an error occurs, then the value *ppPage is set to is undefined. It
** may remain unchanged, or it may be set to an invalid value.
*/
static int getAndInitPage(
BtShared *pBt, /* The database file */
@@ -1550,39 +1553,25 @@ static int getAndInitPage(
MemPage **ppPage /* Write the page pointer here */
){
int rc;
MemPage *pPage;
TESTONLY( Pgno iLastPg = pagerPagecount(pBt); )
assert( sqlite3_mutex_held(pBt->mutex) );
if( pgno==0 ){
return SQLITE_CORRUPT_BKPT;
rc = btreeGetPage(pBt, pgno, ppPage, 0);
if( rc==SQLITE_OK ){
rc = btreeInitPage(*ppPage);
if( rc!=SQLITE_OK ){
releasePage(*ppPage);
}
}
/* It is often the case that the page we want is already in cache.
** If so, get it directly. This saves us from having to call
** pagerPagecount() to make sure pgno is within limits, which results
** in a measureable performance improvements.
*/
*ppPage = pPage = btreePageLookup(pBt, pgno);
if( pPage ){
/* Page is already in cache */
rc = SQLITE_OK;
}else{
/* Page not in cache. Acquire it. */
testcase( pgno==pagerPagecount(pBt) );
if( pgno>pagerPagecount(pBt) ){
return SQLITE_CORRUPT_BKPT;
}
rc = btreeGetPage(pBt, pgno, ppPage, 0);
if( rc ) return rc;
pPage = *ppPage;
}
if( !pPage->isInit ){
rc = btreeInitPage(pPage);
}
if( rc!=SQLITE_OK ){
releasePage(pPage);
*ppPage = 0;
}
/* If the requested page number was either 0 or greater than the page
** number of the last page in the database, this function should return
** SQLITE_CORRUPT or some other error (i.e. SQLITE_FULL). Check that this
** is the case. */
assert( (pgno>0 && pgno<=iLastPg) || rc!=SQLITE_OK );
testcase( pgno==0 );
testcase( pgno==iLastPg );
return rc;
}
@@ -2207,6 +2196,8 @@ static int lockBtree(BtShared *pBt){
assert( sqlite3_mutex_held(pBt->mutex) );
assert( pBt->pPage1==0 );
rc = sqlite3PagerSharedLock(pBt->pPager);
if( rc!=SQLITE_OK ) return rc;
rc = btreeGetPage(pBt, 1, &pPage1, 0);
if( rc!=SQLITE_OK ) return rc;
@@ -5705,7 +5696,7 @@ static int balance_nonroot(
while( 1 ){
rc = getAndInitPage(pBt, pgno, &apOld[i]);
if( rc ){
memset(apOld, 0, i*sizeof(MemPage*));
memset(apOld, 0, (i+1)*sizeof(MemPage*));
goto balance_cleanup;
}
nMaxCells += 1+apOld[i]->nCell+apOld[i]->nOverflow;