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Overview
| Comment: | Faster loading of cell pointers into the b.apCell array in balance_nonroot. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | btree-opt2 |
| Files: | files | file ages | folders |
| SHA1: |
fda89b0512477f9da09fd0f4e548ed4b |
| User & Date: | drh 2015-06-23 17:09:53.066 |
Context
|
2015-06-23
| ||
| 18:24 | Multiple overflow cells are always adjacent and sequential. Exploit this invariant for a small size reduction and performance increase and add assert()s to prove the invariant. (check-in: f77f2f48f4 user: drh tags: btree-opt2) | |
| 17:09 | Faster loading of cell pointers into the b.apCell array in balance_nonroot. (check-in: fda89b0512 user: drh tags: btree-opt2) | |
| 16:00 | Avoid unnecessary cachedCellSize() calls in the cell partition adjustment phase of balance_nonroot(). (check-in: 6319ee1256 user: drh tags: btree-opt2) | |
Changes
Changes to src/btree.c.
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952 953 954 955 956 957 958 | ** the page, 1 means the second cell, and so forth) return a pointer ** to the cell content. ** ** This routine works only for pages that do not contain overflow cells. */ #define findCell(P,I) \ ((P)->aData + ((P)->maskPage & get2byte(&(P)->aCellIdx[2*(I)]))) | < | 952 953 954 955 956 957 958 959 960 961 962 963 964 965 | ** the page, 1 means the second cell, and so forth) return a pointer ** to the cell content. ** ** This routine works only for pages that do not contain overflow cells. */ #define findCell(P,I) \ ((P)->aData + ((P)->maskPage & get2byte(&(P)->aCellIdx[2*(I)]))) /* ** Sort the overflow cells of a page into index order. ** ** An O(N*N) algorithm is used. But that should not be a problem ** since N is only very rarely more than 1. */ |
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7050 7051 7052 7053 7054 7055 7056 |
leafCorrection = b.pRef->leaf*4;
leafData = b.pRef->intKeyLeaf;
for(i=0; i<nOld; i++){
MemPage *pOld = apOld[i];
int limit = pOld->nCell;
u8 *aData = pOld->aData;
u16 maskPage = pOld->maskPage;
| | < | | > | > | | > < | 7049 7050 7051 7052 7053 7054 7055 7056 7057 7058 7059 7060 7061 7062 7063 7064 7065 7066 7067 7068 7069 7070 7071 7072 7073 7074 7075 7076 7077 7078 7079 7080 7081 7082 7083 7084 7085 7086 7087 7088 7089 7090 7091 7092 7093 7094 7095 7096 7097 7098 7099 7100 7101 7102 7103 |
leafCorrection = b.pRef->leaf*4;
leafData = b.pRef->intKeyLeaf;
for(i=0; i<nOld; i++){
MemPage *pOld = apOld[i];
int limit = pOld->nCell;
u8 *aData = pOld->aData;
u16 maskPage = pOld->maskPage;
u8 *piCell = aData + pOld->cellOffset;
/* Verify that all sibling pages are of the same "type" (table-leaf,
** table-interior, index-leaf, or index-interior).
*/
if( pOld->aData[0]!=apOld[0]->aData[0] ){
rc = SQLITE_CORRUPT_BKPT;
goto balance_cleanup;
}
/* Load b.apCell[] with pointers to all cells in pOld. Intersperse
** overflow cells in the correct sequence.
**
** This must be done in advance. Once the balance starts, the cell
** offset section of the btree page will be overwritten and we will no
** long be able to find the cells if a pointer to each cell is not saved
** first.
*/
memset(&b.szCell[b.nCell], 0, sizeof(b.szCell[0])*limit);
if( pOld->nOverflow>0 ){
memset(&b.szCell[b.nCell+limit], 0, sizeof(b.szCell[0])*pOld->nOverflow);
btreeSortOverflow(pOld);
for(j=k=0; k<pOld->nOverflow; k++){
limit = pOld->aiOvfl[k] - k;
while( j<limit ){
b.apCell[b.nCell] = aData + (maskPage & get2byte(piCell));
piCell += 2;
b.nCell++;
j++;
}
b.apCell[b.nCell] = pOld->apOvfl[k];
b.nCell++;
}
limit = pOld->nCell - j;
}
limit += b.nCell;
while( b.nCell<limit ){
assert( b.nCell<nMaxCells );
b.apCell[b.nCell] = aData + (maskPage & get2byte(piCell));
piCell += 2;
b.nCell++;
}
cntOld[i] = b.nCell;
if( i<nOld-1 && !leafData){
u16 sz = (u16)szNew[i];
u8 *pTemp;
assert( b.nCell<nMaxCells );
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