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Overview
| Comment: | Reduce the amount of memcpy() required by defragmentPage(). |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | defrag-opt |
| Files: | files | file ages | folders |
| SHA1: |
3edab9957cc7bb90b52fd40b02613c2c |
| User & Date: | drh 2014-09-27 05:00:25.096 |
Context
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2014-10-09
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| 19:35 | Change the balance_nonroot() routine to reduce the amount of memcpy work that takes place. This is a work in progress. (check-in: 29304499ea user: dan tags: defrag-opt) | |
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2014-09-27
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| 05:00 | Reduce the amount of memcpy() required by defragmentPage(). (check-in: 3edab9957c user: drh tags: defrag-opt) | |
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2014-09-26
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| 02:41 | Fix the "PRAGMA integrity_check" command so that it avoids formatting error message context messages until it actually needs to generate an error message. This avoids much formatting, and hence greatly improves the performance of "PRAGMA integrity_check" in the common case when there are no errors. It also makes the code a little smaller. (check-in: 8391351583 user: drh tags: trunk) | |
Changes
Changes to src/btree.c.
| ︙ | ︙ | |||
1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 | int size; /* Size of a cell */ int usableSize; /* Number of usable bytes on a page */ int cellOffset; /* Offset to the cell pointer array */ int cbrk; /* Offset to the cell content area */ int nCell; /* Number of cells on the page */ unsigned char *data; /* The page data */ unsigned char *temp; /* Temp area for cell content */ int iCellFirst; /* First allowable cell index */ int iCellLast; /* Last possible cell index */ assert( sqlite3PagerIswriteable(pPage->pDbPage) ); assert( pPage->pBt!=0 ); assert( pPage->pBt->usableSize <= SQLITE_MAX_PAGE_SIZE ); assert( pPage->nOverflow==0 ); assert( sqlite3_mutex_held(pPage->pBt->mutex) ); | > | | < < | < > > > > > > > > > | 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 |
int size; /* Size of a cell */
int usableSize; /* Number of usable bytes on a page */
int cellOffset; /* Offset to the cell pointer array */
int cbrk; /* Offset to the cell content area */
int nCell; /* Number of cells on the page */
unsigned char *data; /* The page data */
unsigned char *temp; /* Temp area for cell content */
unsigned char *src; /* Source of content */
int iCellFirst; /* First allowable cell index */
int iCellLast; /* Last possible cell index */
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
assert( pPage->pBt!=0 );
assert( pPage->pBt->usableSize <= SQLITE_MAX_PAGE_SIZE );
assert( pPage->nOverflow==0 );
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
temp = 0;
src = data = pPage->aData;
hdr = pPage->hdrOffset;
cellOffset = pPage->cellOffset;
nCell = pPage->nCell;
assert( nCell==get2byte(&data[hdr+3]) );
usableSize = pPage->pBt->usableSize;
cbrk = usableSize;
iCellFirst = cellOffset + 2*nCell;
iCellLast = usableSize - 4;
for(i=0; i<nCell; i++){
u8 *pAddr; /* The i-th cell pointer */
pAddr = &data[cellOffset + i*2];
pc = get2byte(pAddr);
testcase( pc==iCellFirst );
testcase( pc==iCellLast );
#if !defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
/* These conditions have already been verified in btreeInitPage()
** if SQLITE_ENABLE_OVERSIZE_CELL_CHECK is defined
*/
if( pc<iCellFirst || pc>iCellLast ){
return SQLITE_CORRUPT_BKPT;
}
#endif
assert( pc>=iCellFirst && pc<=iCellLast );
size = cellSizePtr(pPage, &src[pc]);
cbrk -= size;
#if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
if( cbrk<iCellFirst ){
return SQLITE_CORRUPT_BKPT;
}
#else
if( cbrk<iCellFirst || pc+size>usableSize ){
return SQLITE_CORRUPT_BKPT;
}
#endif
assert( cbrk+size<=usableSize && cbrk>=iCellFirst );
testcase( cbrk+size==usableSize );
testcase( pc+size==usableSize );
put2byte(pAddr, cbrk);
if( temp==0 ){
int x;
if( cbrk==pc ) continue;
temp = sqlite3PagerTempSpace(pPage->pBt->pPager);
x = get2byte(&data[hdr+5]);
memcpy(&temp[x], &data[x], (cbrk+size) - x);
src = temp;
}
memcpy(&data[cbrk], &src[pc], size);
}
assert( cbrk>=iCellFirst );
put2byte(&data[hdr+5], cbrk);
data[hdr+1] = 0;
data[hdr+2] = 0;
data[hdr+7] = 0;
memset(&data[iCellFirst], 0, cbrk-iCellFirst);
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| ︙ | ︙ | |||
5951 5952 5953 5954 5955 5956 5957 |
&& (int)MX_CELL(pPage->pBt)<=10921);
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
/* Check that the page has just been zeroed by zeroPage() */
assert( pPage->nCell==0 );
assert( get2byteNotZero(&data[hdr+5])==nUsable );
| | | < > | 5958 5959 5960 5961 5962 5963 5964 5965 5966 5967 5968 5969 5970 5971 5972 5973 5974 5975 5976 5977 5978 |
&& (int)MX_CELL(pPage->pBt)<=10921);
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
/* Check that the page has just been zeroed by zeroPage() */
assert( pPage->nCell==0 );
assert( get2byteNotZero(&data[hdr+5])==nUsable );
pCellptr = pPage->aCellIdx;
cellbody = nUsable;
for(i=0; i<nCell; i++){
u16 sz = aSize[i];
cellbody -= sz;
put2byte(pCellptr, cellbody);
pCellptr += 2;
memcpy(&data[cellbody], apCell[i], sz);
}
put2byte(&data[hdr+3], nCell);
put2byte(&data[hdr+5], cellbody);
pPage->nFree -= (nCell*2 + nUsable - cellbody);
pPage->nCell = (u16)nCell;
}
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| ︙ | ︙ |