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Overview
Comment:Avoid reading the file-size before page 1 is read-locked.
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Timelines: family | ancestors | descendants | both | server-edition
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SHA3-256: f6b025bf632501f51e691a05d309225671fd78bc62c9a43dd916d35ba4cf6d0e
User & Date: dan 2017-04-29 15:48:32.290
Context
2017-05-01
20:07
Update this branch with latest trunk changes. (check-in: 83b1e163ef user: dan tags: server-edition)
2017-04-29
15:48
Avoid reading the file-size before page 1 is read-locked. (check-in: f6b025bf63 user: dan tags: server-edition)
2017-04-28
17:32
Fix various bugs revealed by running performance tests. (check-in: a40b42c422 user: dan tags: server-edition)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/btree.c.
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  if( rc!=SQLITE_OK ) return rc;

  /* Do some checking to help insure the file we opened really is
  ** a valid database file. 
  */
  nPage = nPageHeader = get4byte(28+(u8*)pPage1->aData);
  sqlite3PagerPagecount(pBt->pPager, &nPageFile);
#ifdef SQLITE_SERVER_EDITION
  if( sqlite3PagerIsServer(pBt->pPager) ){
    sqlite3PagerSetPagecount(pBt->pPager, nPage);
    nPageFile = nPage;
  }
#endif
  if( nPage==0 || memcmp(24+(u8*)pPage1->aData, 92+(u8*)pPage1->aData,4)!=0 ){
    nPage = nPageFile;
  }
  if( nPage>0 ){
    u32 pageSize;
    u32 usableSize;
    u8 *page1 = pPage1->aData;








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  if( rc!=SQLITE_OK ) return rc;

  /* Do some checking to help insure the file we opened really is
  ** a valid database file. 
  */
  nPage = nPageHeader = get4byte(28+(u8*)pPage1->aData);
  sqlite3PagerPagecount(pBt->pPager, &nPageFile);






  if( nPage==0 || memcmp(24+(u8*)pPage1->aData, 92+(u8*)pPage1->aData,4)!=0 ){
    nPage = nPageFile;
  }
  if( nPage>0 ){
    u32 pageSize;
    u32 usableSize;
    u8 *page1 = pPage1->aData;
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    int i;

    /* Try to lock a free-list trunk. If bAlloc is true, it has to be a
    ** free-list trunk with at least one entry in the free-list. */
    nList = (int)get4byte(&pNode->aData[4]);
    for(i=0; i<nList; i++){
      Pgno iTrunk = get4byte(&pNode->aData[8+i*4]);
      if( SQLITE_OK==sqlite3PagerWritelock(pBt->pPager, iTrunk) ){
        rc = btreeGetUnusedPage(pBt, iTrunk, &pTrunk, 0);
        if( rc==SQLITE_OK && bAlloc ){
          if( !get4byte(&pTrunk->aData[0]) && !get4byte(&pTrunk->aData[4]) ){
            releasePage(pTrunk);
            pTrunk = 0;
          }
        }








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    int i;

    /* Try to lock a free-list trunk. If bAlloc is true, it has to be a
    ** free-list trunk with at least one entry in the free-list. */
    nList = (int)get4byte(&pNode->aData[4]);
    for(i=0; i<nList; i++){
      Pgno iTrunk = get4byte(&pNode->aData[8+i*4]);
      if( SQLITE_OK==sqlite3PagerPagelock(pBt->pPager, iTrunk, 1) ){
        rc = btreeGetUnusedPage(pBt, iTrunk, &pTrunk, 0);
        if( rc==SQLITE_OK && bAlloc ){
          if( !get4byte(&pTrunk->aData[0]) && !get4byte(&pTrunk->aData[4]) ){
            releasePage(pTrunk);
            pTrunk = 0;
          }
        }
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Changes to src/pager.c.
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}
#endif

#ifdef SQLITE_SERVER_EDITION
int sqlite3PagerIsServer(Pager *pPager){
  return pagerIsServer(pPager);
}
int sqlite3PagerWritelock(Pager *pPager, Pgno pgno){
  return sqlite3ServerLock(pPager->pServer, pgno, 1);
}
void sqlite3PagerSetPagecount(Pager *pPager, u32 nPage){
  assert( pPager->eState==PAGER_READER );
  pPager->dbSize = nPage;
}
#endif

#endif /* SQLITE_OMIT_DISKIO */








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}
#endif

#ifdef SQLITE_SERVER_EDITION
int sqlite3PagerIsServer(Pager *pPager){
  return pagerIsServer(pPager);
}
int sqlite3PagerPagelock(Pager *pPager, Pgno pgno, int bWrite){
  return sqlite3ServerLock(pPager->pServer, pgno, bWrite);




}
#endif

#endif /* SQLITE_OMIT_DISKIO */
Changes to src/pager.h.
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# define disable_simulated_io_errors()
# define enable_simulated_io_errors()
#endif

#ifdef SQLITE_SERVER_EDITION
  int sqlite3PagerRollbackJournal(Pager*, int);
  int sqlite3PagerIsServer(Pager *pPager);
  int sqlite3PagerWritelock(Pager *pPager, Pgno);
  void sqlite3PagerSetPagecount(Pager*, u32);
#endif

#endif /* SQLITE_PAGER_H */








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# define disable_simulated_io_errors()
# define enable_simulated_io_errors()
#endif

#ifdef SQLITE_SERVER_EDITION
  int sqlite3PagerRollbackJournal(Pager*, int);
  int sqlite3PagerIsServer(Pager *pPager);
  int sqlite3PagerPagelock(Pager *pPager, Pgno, int);

#endif

#endif /* SQLITE_PAGER_H */
Changes to src/server.c.
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/*
** Begin a transaction.
*/
int sqlite3ServerBegin(Server *p){
#if 0
  return posixLock(p->pHma->fd, p->iClient+1, SERVER_WRITE_LOCK, 0);
#endif
  return SQLITE_OK;
}

/*
** End a transaction (and release all locks).
*/
int sqlite3ServerEnd(Server *p){
  int i;








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/*
** Begin a transaction.
*/
int sqlite3ServerBegin(Server *p){
#if 0
  return posixLock(p->pHma->fd, p->iClient+1, SERVER_WRITE_LOCK, 0);
#endif
  return sqlite3ServerLock(p, 1, 0);
}

/*
** End a transaction (and release all locks).
*/
int sqlite3ServerEnd(Server *p){
  int i;
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