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Auto-vacuum: Account for the page reserved for windows locking (PENDING_BYTE). (CVS 2076)

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FossilOrigin-Name: d6335698696c7b651bbc436c5177d87eb57a8934
This commit is contained in:
danielk1977
2004-11-08 07:13:13 +00:00
parent e497f0051f
commit 599fcbae56
5 changed files with 76 additions and 29 deletions
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58
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 1.213 2004/11/06 12:26:08 danielk1977 Exp $
** $Id: btree.c,v 1.214 2004/11/08 07:13:14 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
@@ -394,8 +394,13 @@ static void put4byte(unsigned char *p, u32 v){
#define getVarint32 sqlite3GetVarint32
#define putVarint sqlite3PutVarint
#ifndef SQLITE_OMIT_AUTOVACUUM
/* The database page the PENDING_BYTE occupies. This page is never used.
** TODO: This macro is very similary to PAGER_MJ_PGNO() in pager.c. They
** should possibly be consolidated (presumably in pager.h).
*/
#define PENDING_BYTE_PAGE(pBt) ((PENDING_BYTE/(pBt)->pageSize)+1)
#ifndef SQLITE_OMIT_AUTOVACUUM
/*
** These two macros define the location of the pointer-map entry for a
** database page. The first argument to each is the page size used
@@ -408,11 +413,11 @@ static void put4byte(unsigned char *p, u32 v){
**
** If the pgno argument passed to PTRMAP_PAGENO is a pointer-map page,
** then pgno is returned. So (pgno==PTRMAP_PAGENO(pgsz, pgno)) can be
** used to test if pgno is a pointer-map page.
** used to test if pgno is a pointer-map page. PTRMAP_ISPAGE implements
** this test.
*/
#define PTRMAP_PAGENO(pgsz, pgno) (((pgno-2)/(pgsz/5+1))*(pgsz/5+1)+2)
#define PTRMAP_PTROFFSET(pgsz, pgno) (((pgno-2)%(pgsz/5+1)-1)*5)
#define PTRMAP_ISPAGE(pgsz, pgno) (PTRMAP_PAGENO(pgsz,pgno)==pgno)
/*
@@ -459,6 +464,7 @@ static int ptrmapPut(Btree *pBt, Pgno key, u8 eType, Pgno pgno){
int offset; /* Offset in pointer map page */
int rc;
assert( key!=0 );
iPtrmap = PTRMAP_PAGENO(pBt->pageSize, key);
rc = sqlite3pager_get(pBt->pPager, iPtrmap, (void **)&pPtrmap);
if( rc!=SQLITE_OK ){
@@ -1755,6 +1761,12 @@ static int autoVacuumCommit(Btree *pBt, Pgno *nTrunc){
origSize = sqlite3pager_pagecount(pPager);
nPtrMap = (nFreeList-origSize+PTRMAP_PAGENO(pgsz, origSize)+pgsz/5)/(pgsz/5);
finSize = origSize - nFreeList - nPtrMap;
if( origSize>PENDING_BYTE_PAGE(pBt) && finSize<=PENDING_BYTE_PAGE(pBt) ){
finSize--;
if( PTRMAP_ISPAGE(pBt->pageSize, finSize) ){
finSize--;
}
}
TRACE(("AUTOVACUUM: Begin (db size %d->%d)\n", origSize, finSize));
/* Variable 'finSize' will be the size of the file in pages after
@@ -1764,14 +1776,17 @@ static int autoVacuumCommit(Btree *pBt, Pgno *nTrunc){
** to a free page earlier in the file (somewhere before finSize).
*/
for( iDbPage=finSize+1; iDbPage<=origSize; iDbPage++ ){
/* If iDbPage is a pointer map page, or the pending-byte page, skip it. */
if( PTRMAP_ISPAGE(pgsz, iDbPage) || iDbPage==PENDING_BYTE_PAGE(pBt) ){
continue;
}
rc = ptrmapGet(pBt, iDbPage, &eType, &iPtrPage);
if( rc!=SQLITE_OK ) goto autovacuum_out;
assert( eType!=PTRMAP_ROOTPAGE );
/* If iDbPage is a free or pointer map page, do not swap it.
** TODO: Instead, make sure the page is in the journal file.
*/
if( eType==PTRMAP_FREEPAGE || PTRMAP_ISPAGE(pgsz, iDbPage) ){
/* If iDbPage is free, do not swap it. */
if( eType==PTRMAP_FREEPAGE ){
continue;
}
rc = getPage(pBt, iDbPage, &pDbMemPage);
@@ -3052,15 +3067,19 @@ static int allocatePage(
** becomes a new pointer-map page, the second is used by the caller.
*/
TRACE(("ALLOCATE: %d from end of file (pointer-map page)\n", *pPgno));
assert( *pPgno!=PENDING_BYTE_PAGE(pBt) );
(*pPgno)++;
}
#endif
assert( *pPgno!=PENDING_BYTE_PAGE(pBt) );
rc = getPage(pBt, *pPgno, ppPage);
if( rc ) return rc;
rc = sqlite3pager_write((*ppPage)->aData);
TRACE(("ALLOCATE: %d from end of file\n", *pPgno));
}
assert( *pPgno!=PENDING_BYTE_PAGE(pBt) );
return rc;
}
@@ -4383,8 +4402,11 @@ int sqlite3BtreeCreateTable(Btree *pBt, int *piTable, int flags){
if( rc!=SQLITE_OK ) return rc;
pgnoRoot++;
/* The new root-page may not be allocated on a pointer-map page. */
if( pgnoRoot==PTRMAP_PAGENO(pBt->pageSize, pgnoRoot) ){
/* The new root-page may not be allocated on a pointer-map page, or the
** PENDING_BYTE page.
*/
if( pgnoRoot==PTRMAP_PAGENO(pBt->pageSize, pgnoRoot) ||
pgnoRoot==PENDING_BYTE_PAGE(pBt) ){
pgnoRoot++;
}
assert( pgnoRoot>=3 );
@@ -4616,10 +4638,20 @@ int sqlite3BtreeDropTable(Btree *pBt, int iTable, int *piMoved){
*piMoved = maxRootPgno;
}
/* Set the new 'max-root-page' value in the database header. This
** is the old value less one, less one more if that happens to
** be a root-page number, less one again if that is the
** PENDING_BYTE_PAGE.
*/
maxRootPgno--;
if( maxRootPgno==PENDING_BYTE_PAGE(pBt) ){
maxRootPgno--;
}
if( maxRootPgno==PTRMAP_PAGENO(pBt->pageSize, maxRootPgno) ){
maxRootPgno--;
}
assert( maxRootPgno!=PENDING_BYTE_PAGE(pBt) );
rc = sqlite3BtreeUpdateMeta(pBt, 4, maxRootPgno);
}else{
rc = freePage(pPage);
@@ -4655,9 +4687,9 @@ int sqlite3BtreeGetMeta(Btree *pBt, int idx, u32 *pMeta){
*pMeta = get4byte(&pP1[36 + idx*4]);
sqlite3pager_unref(pP1);
/* If autovacuumed is disabled in the implementation but we are
** trying to access an autovacuumed database, then make the
** database readonly. */
/* If autovacuumed is disabled in this build but we are trying to
** access an autovacuumed database, then make the database readonly.
*/
#ifdef SQLITE_OMIT_AUTOVACUUM
if( idx==4 && *pMeta>0 ) pBt->readOnly = 1;
#endif