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Ensure that empty space on pages is zeroed before they are written to disk.

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This helps with compressed databases, and stops valgrind complaining about
uninitialized bytes and write().

FossilOrigin-Name: 5ffec5db33137251090d45e2ca7e3e7823e3215ae89822d905923424ceba2ac2
This commit is contained in:
dan
2017-11-16 20:48:47 +00:00
parent 3dbb4acf07
commit cda185d3a2
3 changed files with 50 additions and 32 deletions
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66
ext/lsm1/lsm_sorted.c
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@ -92,7 +92,7 @@
#define SEGMENT_POINTER_OFFSET(pgsz) ((pgsz) - 2 - 2 - 8)
#define SEGMENT_CELLPTR_OFFSET(pgsz, iCell) ((pgsz) - 2 - 2 - 8 - 2 - (iCell)*2)
#define SEGMENT_EOF(pgsz, nEntry) SEGMENT_CELLPTR_OFFSET(pgsz, nEntry)
#define SEGMENT_EOF(pgsz, nEntry) SEGMENT_CELLPTR_OFFSET(pgsz, nEntry-1)
#define SEGMENT_BTREE_FLAG 0x0001
#define PGFTR_SKIP_NEXT_FLAG 0x0002
@ -3999,6 +3999,11 @@ static int mergeWorkerWrite(
** marked read-only, advance to the next page of the output run. */
iOff = pMerge->iOutputOff;
if( iOff<0 || pPg==0 || iOff+nHdr > SEGMENT_EOF(nData, nRec+1) ){
if( iOff>=0 && pPg ){
/* Zero any free space on the page */
assert( aData );
memset(&aData[iOff], 0, SEGMENT_EOF(nData, nRec)-iOff);
}
iFPtr = (int)*pMW->pCsr->pPrevMergePtr;
iRPtr = iPtr - iFPtr;
iOff = 0;
@ -4069,36 +4074,49 @@ static void mergeWorkerShutdown(MergeWorker *pMW, int *pRc){
/* Unless the merge has finished, save the cursor position in the
** Merge.aInput[] array. See function mergeWorkerInit() for the
** code to restore a cursor position based on aInput[]. */
if( rc==LSM_OK && pCsr && lsmMCursorValid(pCsr) ){
if( rc==LSM_OK && pCsr ){
Merge *pMerge = pMW->pLevel->pMerge;
int bBtree = (pCsr->pBtCsr!=0);
int iPtr;
if( lsmMCursorValid(pCsr) ){
int bBtree = (pCsr->pBtCsr!=0);
int iPtr;
/* pMerge->nInput==0 indicates that this is a FlushTree() operation. */
assert( pMerge->nInput==0 || pMW->pLevel->nRight>0 );
assert( pMerge->nInput==0 || pMerge->nInput==(pCsr->nPtr+bBtree) );
/* pMerge->nInput==0 indicates that this is a FlushTree() operation. */
assert( pMerge->nInput==0 || pMW->pLevel->nRight>0 );
assert( pMerge->nInput==0 || pMerge->nInput==(pCsr->nPtr+bBtree) );
for(i=0; i<(pMerge->nInput-bBtree); i++){
SegmentPtr *pPtr = &pCsr->aPtr[i];
if( pPtr->pPg ){
pMerge->aInput[i].iPg = lsmFsPageNumber(pPtr->pPg);
pMerge->aInput[i].iCell = pPtr->iCell;
for(i=0; i<(pMerge->nInput-bBtree); i++){
SegmentPtr *pPtr = &pCsr->aPtr[i];
if( pPtr->pPg ){
pMerge->aInput[i].iPg = lsmFsPageNumber(pPtr->pPg);
pMerge->aInput[i].iCell = pPtr->iCell;
}else{
pMerge->aInput[i].iPg = 0;
pMerge->aInput[i].iCell = 0;
}
}
if( bBtree && pMerge->nInput ){
assert( i==pCsr->nPtr );
btreeCursorPosition(pCsr->pBtCsr, &pMerge->aInput[i]);
}
/* Store the location of the split-key */
iPtr = pCsr->aTree[1] - CURSOR_DATA_SEGMENT;
if( iPtr<pCsr->nPtr ){
pMerge->splitkey = pMerge->aInput[iPtr];
}else{
pMerge->aInput[i].iPg = 0;
pMerge->aInput[i].iCell = 0;
btreeCursorSplitkey(pCsr->pBtCsr, &pMerge->splitkey);
}
}
if( bBtree && pMerge->nInput ){
assert( i==pCsr->nPtr );
btreeCursorPosition(pCsr->pBtCsr, &pMerge->aInput[i]);
}
/* Store the location of the split-key */
iPtr = pCsr->aTree[1] - CURSOR_DATA_SEGMENT;
if( iPtr<pCsr->nPtr ){
pMerge->splitkey = pMerge->aInput[iPtr];
}else{
btreeCursorSplitkey(pCsr->pBtCsr, &pMerge->splitkey);
/* Zero any free space left on the final page. This helps with
** compression if using a compression hook. And prevents valgrind
** from complaining about uninitialized byte passed to write(). */
if( pMW->pPage ){
int nData;
u8 *aData = fsPageData(pMW->pPage, &nData);
int iOff = pMerge->iOutputOff;
int iEof = SEGMENT_EOF(nData, pageGetNRec(aData, nData));
memset(&aData[iOff], 0, iEof - iOff);
}
pMerge->iOutputOff = -1;