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Avoid constantly freeing and reallocing small internal buffers associated with

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LSM cursors. Instead, allow them to persist for the lifetime of the cursor if
they are LSM_SEGMENTPTR_FREE_THRESHOLD (default 1024) bytes or smaller.

FossilOrigin-Name: bacfe8cb3e4d3be736c6789b2ce55ef5603e5c7a289b05b37cae2203cd7f2290
This commit is contained in:
dan
2017-06-30 11:44:11 +00:00
parent a501f7dab4
commit a5b55e370f
3 changed files with 32 additions and 23 deletions
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39
ext/lsm1/lsm_sorted.c
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@ -98,6 +98,11 @@
#define PGFTR_SKIP_NEXT_FLAG 0x0002
#define PGFTR_SKIP_THIS_FLAG 0x0004
#ifndef LSM_SEGMENTPTR_FREE_THRESHOLD
# define LSM_SEGMENTPTR_FREE_THRESHOLD 1024
#endif
typedef struct SegmentPtr SegmentPtr;
typedef struct Blob Blob;
@ -1148,7 +1153,11 @@ static void sortedSplitkey(lsm_db *pDb, Level *pLevel, int *pRc){
*pRc = rc;
}
static void segmentPtrReset(SegmentPtr *pPtr){
/*
** Reset a segment cursor. Also free its buffers if they are nThreshold
** bytes or larger in size.
*/
static void segmentPtrReset(SegmentPtr *pPtr, int nThreshold){
lsmFsPageRelease(pPtr->pPg);
pPtr->pPg = 0;
pPtr->nCell = 0;
@ -1158,8 +1167,8 @@ static void segmentPtrReset(SegmentPtr *pPtr){
pPtr->nVal = 0;
pPtr->eType = 0;
pPtr->iCell = 0;
sortedBlobFree(&pPtr->blob1);
sortedBlobFree(&pPtr->blob2);
if( pPtr->blob1.nAlloc>=nThreshold ) sortedBlobFree(&pPtr->blob1);
if( pPtr->blob2.nAlloc>=nThreshold ) sortedBlobFree(&pPtr->blob2);
}
static int segmentPtrIgnoreSeparators(MultiCursor *pCsr, SegmentPtr *pPtr){
@ -1206,7 +1215,7 @@ static int segmentPtrAdvance(
rtTopic(pPtr->eType), pPtr->pKey, pPtr->nKey,
pLvl->iSplitTopic, pLvl->pSplitKey, pLvl->nSplitKey
);
if( res<0 ) segmentPtrReset(pPtr);
if( res<0 ) segmentPtrReset(pPtr, LSM_SEGMENTPTR_FREE_THRESHOLD);
}
if( pPtr->pPg==0 && (svFlags & LSM_END_DELETE) ){
@ -1275,7 +1284,7 @@ static int segmentPtrEnd(MultiCursor *pCsr, SegmentPtr *pPtr, int bLast){
rtTopic(pPtr->eType), pPtr->pKey, pPtr->nKey,
pLvl->iSplitTopic, pLvl->pSplitKey, pLvl->nSplitKey
);
if( res<0 ) segmentPtrReset(pPtr);
if( res<0 ) segmentPtrReset(pPtr, LSM_SEGMENTPTR_FREE_THRESHOLD);
}
}
@ -1611,7 +1620,7 @@ static int segmentPtrFwdPointer(
rc = ptrFwdPointer(ptr.pPg, ptr.iCell, ptr.pSeg, &iOut, &bFound);
ptr.pPg = 0;
}
segmentPtrReset(&ptr);
segmentPtrReset(&ptr, 0);
}
*piPtr = iOut;
@ -1658,7 +1667,7 @@ static int segmentPtrSeek(
|| lsmFsDbPageIsLast(pPtr->pSeg, pPtr->pPg)
);
if( pPtr->nCell==0 ){
segmentPtrReset(pPtr);
segmentPtrReset(pPtr, LSM_SEGMENTPTR_FREE_THRESHOLD);
}else{
iMin = 0;
iMax = pPtr->nCell-1;
@ -1716,7 +1725,7 @@ static int segmentPtrSeek(
}
pCsr->flags |= CURSOR_SEEK_EQ;
}
segmentPtrReset(pPtr);
segmentPtrReset(pPtr, LSM_SEGMENTPTR_FREE_THRESHOLD);
break;
}
case LSM_SEEK_LE:
@ -1943,7 +1952,7 @@ static int seekInLevel(
rtTopic(pPtr->eType), pPtr->pKey, pPtr->nKey,
pLvl->iSplitTopic, pLvl->pSplitKey, pLvl->nSplitKey
);
if( res<0 ) segmentPtrReset(pPtr);
if( res<0 ) segmentPtrReset(pPtr, LSM_SEGMENTPTR_FREE_THRESHOLD);
}
if( aPtr[i].pKey ) bHit = 1;
@ -2219,7 +2228,7 @@ static void mcursorFreeComponents(MultiCursor *pCsr){
/* Reset the segment pointers */
for(i=0; i<pCsr->nPtr; i++){
segmentPtrReset(&pCsr->aPtr[i]);
segmentPtrReset(&pCsr->aPtr[i], 0);
}
/* And the b-tree cursor, if any */
@ -2874,7 +2883,7 @@ static int multiCursorEnd(MultiCursor *pCsr, int bLast){
if( bHit==0 && rc==LSM_OK ){
rc = segmentPtrEnd(pCsr, pPtr, 1);
}else{
segmentPtrReset(pPtr);
segmentPtrReset(pPtr, LSM_SEGMENTPTR_FREE_THRESHOLD);
}
}else{
int bLhs = (pPtr->pSeg==&pLvl->lhs);
@ -2886,7 +2895,7 @@ static int multiCursorEnd(MultiCursor *pCsr, int bLast){
}
for(iRhs=0; iRhs<pLvl->nRight && rc==LSM_OK; iRhs++){
if( bHit ){
segmentPtrReset(&pPtr[iRhs+1]);
segmentPtrReset(&pPtr[iRhs+1], LSM_SEGMENTPTR_FREE_THRESHOLD);
}else{
rc = sortedRhsFirst(pCsr, pLvl, &pPtr[iRhs+bLhs]);
}
@ -2969,7 +2978,7 @@ void lsmMCursorReset(MultiCursor *pCsr){
lsmTreeCursorReset(pCsr->apTreeCsr[0]);
lsmTreeCursorReset(pCsr->apTreeCsr[1]);
for(i=0; i<pCsr->nPtr; i++){
segmentPtrReset(&pCsr->aPtr[i]);
segmentPtrReset(&pCsr->aPtr[i], LSM_SEGMENTPTR_FREE_THRESHOLD);
}
pCsr->key.nData = 0;
}
@ -6079,8 +6088,8 @@ static int assertPointersOk(
}
}
segmentPtrReset(&ptr1);
segmentPtrReset(&ptr2);
segmentPtrReset(&ptr1, 0);
segmentPtrReset(&ptr2, 0);
return LSM_OK;
}