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Merge recent trunk enhancements.

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FossilOrigin-Name: c60cdb47612c05c252613e50a8ac10635469fdfe
This commit is contained in:
drh
2017-03-02 13:22:04 +00:00
parent 555227bec0 76adb23980
commit 8d990b34db
15 changed files with 314 additions and 68 deletions
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64
src/btree.c
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@@ -1317,17 +1317,18 @@ static void ptrmapPutOvflPtr(MemPage *pPage, u8 *pCell, int *pRC){
/*
** Defragment the page given. All Cells are moved to the
** end of the page and all free space is collected into one
** big FreeBlk that occurs in between the header and cell
** pointer array and the cell content area.
** Defragment the page given. This routine reorganizes cells within the
** page so that there are no free-blocks on the free-block list.
**
** Parameter nMaxFrag is the maximum amount of fragmented space that may be
** present in the page after this routine returns.
**
** EVIDENCE-OF: R-44582-60138 SQLite may from time to time reorganize a
** b-tree page so that there are no freeblocks or fragment bytes, all
** unused bytes are contained in the unallocated space region, and all
** cells are packed tightly at the end of the page.
*/
static int defragmentPage(MemPage *pPage){
static int defragmentPage(MemPage *pPage, int nMaxFrag){
int i; /* Loop counter */
int pc; /* Address of the i-th cell */
int hdr; /* Offset to the page header */
@@ -1342,7 +1343,6 @@ static int defragmentPage(MemPage *pPage){
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 );
@@ -1354,10 +1354,44 @@ static int defragmentPage(MemPage *pPage){
cellOffset = pPage->cellOffset;
nCell = pPage->nCell;
assert( nCell==get2byte(&data[hdr+3]) );
iCellFirst = cellOffset + 2*nCell;
/* This block handles pages with two or fewer free blocks and nMaxFrag
** or fewer fragmented bytes. In this case it is faster to move the
** two (or one) blocks of cells using memmove() and add the required
** offsets to each pointer in the cell-pointer array than it is to
** reconstruct the entire page. */
if( (int)data[hdr+7]<=nMaxFrag ){
int iFree = get2byte(&data[hdr+1]);
if( iFree ){
int iFree2 = get2byte(&data[iFree]);
if( 0==iFree2 || (data[iFree2]==0 && data[iFree2+1]==0) ){
u8 *pEnd = &data[cellOffset + nCell*2];
u8 *pAddr;
int sz2 = 0;
int sz = get2byte(&data[iFree+2]);
int top = get2byte(&data[hdr+5]);
if( iFree2 ){
sz2 = get2byte(&data[iFree2+2]);
memmove(&data[iFree+sz+sz2], &data[iFree+sz], iFree2-(iFree+sz));
sz += sz2;
}
cbrk = top+sz;
memmove(&data[cbrk], &data[top], iFree-top);
for(pAddr=&data[cellOffset]; pAddr<pEnd; pAddr+=2){
pc = get2byte(pAddr);
if( pc<iFree ){ put2byte(pAddr, pc+sz); }
else if( pc<iFree2 ){ put2byte(pAddr, pc+sz2); }
}
goto defragment_out;
}
}
}
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];
@@ -1390,16 +1424,18 @@ static int defragmentPage(MemPage *pPage){
}
memcpy(&data[cbrk], &src[pc], size);
}
data[hdr+7] = 0;
defragment_out:
if( data[hdr+7]+cbrk-iCellFirst!=pPage->nFree ){
return SQLITE_CORRUPT_BKPT;
}
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);
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
if( cbrk-iCellFirst!=pPage->nFree ){
return SQLITE_CORRUPT_BKPT;
}
return SQLITE_OK;
}
@@ -1537,10 +1573,10 @@ static int allocateSpace(MemPage *pPage, int nByte, int *pIdx){
testcase( gap+2+nByte==top );
if( gap+2+nByte>top ){
assert( pPage->nCell>0 || CORRUPT_DB );
rc = defragmentPage(pPage);
rc = defragmentPage(pPage, MIN(4, pPage->nFree - (2+nByte)));
if( rc ) return rc;
top = get2byteNotZero(&data[hdr+5]);
assert( gap+nByte<=top );
assert( gap+2+nByte<=top );
}
@@ -7713,7 +7749,7 @@ static int balance_nonroot(
** free space needs to be up front.
*/
assert( nNew==1 || CORRUPT_DB );
rc = defragmentPage(apNew[0]);
rc = defragmentPage(apNew[0], -1);
testcase( rc!=SQLITE_OK );
assert( apNew[0]->nFree ==
(get2byte(&apNew[0]->aData[5])-apNew[0]->cellOffset-apNew[0]->nCell*2)