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Code to auto-vacuum the database if all root pages happen to be in the right place. Not active by default and largely untested. (CVS 2037)

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FossilOrigin-Name: d12481f09cbe51c7ea499bc22afec5de3af14ad4
This commit is contained in:
danielk1977
2004-11-02 12:56:41 +00:00
parent a82ffef115
commit 687566d786
7 changed files with 578 additions and 62 deletions
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97
src/pager.c
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@@ -18,7 +18,7 @@
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.169 2004/10/31 02:22:49 drh Exp $
** @(#) $Id: pager.c,v 1.170 2004/11/02 12:56:41 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
@@ -2017,10 +2017,22 @@ static int pager_write_pagelist(PgHdr *pList){
while( pList ){
assert( pList->dirty );
sqlite3OsSeek(&pPager->fd, (pList->pgno-1)*(i64)pPager->pageSize);
CODEC(pPager, PGHDR_TO_DATA(pList), pList->pgno, 6);
TRACE3("STORE %d page %d\n", pPager->fd.h, pList->pgno);
rc = sqlite3OsWrite(&pPager->fd, PGHDR_TO_DATA(pList), pPager->pageSize);
CODEC(pPager, PGHDR_TO_DATA(pList), pList->pgno, 0);
/* If there are dirty pages in the page cache with page numbers greater
** than Pager.dbSize, this means sqlite3pager_truncate() was called to
** make the file smaller (presumably by auto-vacuum code). Do not write
** any such pages to the file.
*/
if( pList->pgno<=pPager->dbSize ){
CODEC(pPager, PGHDR_TO_DATA(pList), pList->pgno, 6);
TRACE3("STORE %d page %d\n", pPager->fd.h, pList->pgno);
rc = sqlite3OsWrite(&pPager->fd, PGHDR_TO_DATA(pList), pPager->pageSize);
CODEC(pPager, PGHDR_TO_DATA(pList), pList->pgno, 0);
}
#ifndef NDEBUG
else{
TRACE3("NOSTORE %d page %d\n", pPager->fd.h, pList->pgno);
}
#endif
if( rc ) return rc;
pList->dirty = 0;
pList = pList->pDirty;
@@ -3202,6 +3214,81 @@ sync_exit:
return rc;
}
#ifndef SQLITE_OMIT_AUTOVACUUM
/*
** Move the page identified by pData to location pgno in the file.
**
** There must be no references to the current page pgno. If current page
** pgno is not already in the rollback journal, it is not written there by
** by this routine. The same applies to the page pData refers to on entry to
** this routine.
**
** References to the page refered to by pData remain valid. Updating any
** meta-data associated with page pData (i.e. data stored in the nExtra bytes
** allocated along with the page) is the responsibility of the caller.
**
** A transaction must be active when this routine is called, however it is
** illegal to call this routine if a statment transaction is active.
*/
int sqlite3pager_movepage(Pager *pPager, void *pData, Pgno pgno){
PgHdr *pPg = DATA_TO_PGHDR(pData);
PgHdr *pPgOld;
assert( !pPager->stmtInUse );
/* assert( pPg->pNextFree==0 && pPg->pPrevFree==0 && pPg->nRef>0 ); */
assert( pPg->nRef>0 );
/* Unlink pPg from it's hash-chain */
if( pPg->pNextHash ){
pPg->pNextHash->pPrevHash = pPg->pPrevHash;
}
if( pPg->pPrevHash ){
pPg->pPrevHash->pNextHash = pPg->pNextHash;
}else{
int h = pager_hash(pPg->pgno);
assert( pPager->aHash[h]==pPg );
pPager->aHash[h] = pPg->pNextHash;
}
/* Change the page number for pPg */
pPg->pgno = pgno;
pPgOld = pager_lookup(pPager, pgno);
if( pPgOld ){
/* Remove pPgOld from the page number hash-chain and insert pPg. */
assert(pPgOld->nRef==0 && !pPgOld->pNextStmt && !pPgOld->pPrevStmt );
if( pPgOld->pNextHash ){
pPgOld->pNextHash->pPrevHash = pPg;
}
if( pPgOld->pPrevHash ){
pPgOld->pPrevHash->pNextHash = pPg;
}else{
int h = pager_hash(pgno);
assert( pPager->aHash[h]==pPgOld );
pPager->aHash[h] = pPg;
}
pPgOld->pNextHash = pPgOld->pPrevHash = 0;
}else{
/* Insert pPg into it's new hash-chain. */
int h = pager_hash(pgno);
if( pPager->aHash[h] ){
pPager->aHash[h]->pNextHash = pPg;
}
pPg->pNextHash = pPager->aHash[h];
pPg->pPrevHash = 0;
}
/* Don't write the old page when sqlite3pager_sync() is called. Do write
** the new one.
*/
pPgOld->dirty = 0;
pPg->dirty = 1;
pPager->dirtyCache = 1;
return SQLITE_OK;
}
#endif
#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
/*
** Return the current state of the file lock for the given pager.