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Store values loaded from the stat1 table as logarithmic values in memory.

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FossilOrigin-Name: 1bd74c49ddab6f53bb6eaa57907eff44c2580dd6
This commit is contained in:
dan
2014-04-25 15:01:01 +00:00
parent aa9933c115
commit cfc9df76e1
8 changed files with 72 additions and 51 deletions
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26
src/build.c
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@@ -905,7 +905,7 @@ void sqlite3StartTable(
pTable->iPKey = -1;
pTable->pSchema = db->aDb[iDb].pSchema;
pTable->nRef = 1;
pTable->nRowEst = 1048576;
pTable->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
assert( pParse->pNewTable==0 );
pParse->pNewTable = pTable;
@@ -2730,15 +2730,15 @@ Index *sqlite3AllocateIndexObject(
nByte = ROUND8(sizeof(Index)) + /* Index structure */
ROUND8(sizeof(char*)*nCol) + /* Index.azColl */
ROUND8(sizeof(tRowcnt)*(nCol+1) + /* Index.aiRowEst */
ROUND8(sizeof(LogEst)*(nCol+1) + /* Index.aiRowLogEst */
sizeof(i16)*nCol + /* Index.aiColumn */
sizeof(u8)*nCol); /* Index.aSortOrder */
p = sqlite3DbMallocZero(db, nByte + nExtra);
if( p ){
char *pExtra = ((char*)p)+ROUND8(sizeof(Index));
p->azColl = (char**)pExtra; pExtra += ROUND8(sizeof(char*)*nCol);
p->aiRowEst = (tRowcnt*)pExtra; pExtra += sizeof(tRowcnt)*(nCol+1);
p->aiColumn = (i16*)pExtra; pExtra += sizeof(i16)*nCol;
p->azColl = (char**)pExtra; pExtra += ROUND8(sizeof(char*)*nCol);
p->aiRowLogEst = (LogEst*)pExtra; pExtra += sizeof(LogEst)*(nCol+1);
p->aiColumn = (i16*)pExtra; pExtra += sizeof(i16)*nCol;
p->aSortOrder = (u8*)pExtra;
p->nColumn = nCol;
p->nKeyCol = nCol - 1;
@@ -2968,7 +2968,7 @@ Index *sqlite3CreateIndex(
if( db->mallocFailed ){
goto exit_create_index;
}
assert( EIGHT_BYTE_ALIGNMENT(pIndex->aiRowEst) );
assert( EIGHT_BYTE_ALIGNMENT(pIndex->aiRowLogEst) );
assert( EIGHT_BYTE_ALIGNMENT(pIndex->azColl) );
pIndex->zName = zExtra;
zExtra += nName + 1;
@@ -3249,7 +3249,7 @@ exit_create_index:
** Since we do not know, guess 1 million. aiRowEst[1] is an estimate of the
** number of rows in the table that match any particular value of the
** first column of the index. aiRowEst[2] is an estimate of the number
** of rows that match any particular combiniation of the first 2 columns
** of rows that match any particular combination of the first 2 columns
** of the index. And so forth. It must always be the case that
*
** aiRowEst[N]<=aiRowEst[N-1]
@@ -3260,6 +3260,7 @@ exit_create_index:
** are based on typical values found in actual indices.
*/
void sqlite3DefaultRowEst(Index *pIdx){
#if 0
tRowcnt *a = pIdx->aiRowEst;
int i;
tRowcnt n;
@@ -3274,6 +3275,17 @@ void sqlite3DefaultRowEst(Index *pIdx){
if( pIdx->onError!=OE_None ){
a[pIdx->nKeyCol] = 1;
}
#endif
/* 1000000, 10, 9, 8, 7, 6, 5, 4, 3, 2 */
LogEst aVal[] = { 33, 32, 30, 28, 26, 23, 20, 16, 10 };
LogEst *a = pIdx->aiRowLogEst;
int nCopy = MIN(ArraySize(aVal), pIdx->nKeyCol);
a[0] = pIdx->pTable->nRowLogEst;
memcpy(&a[1], aVal, nCopy*sizeof(LogEst));
if( pIdx->onError!=OE_None ){
a[pIdx->nKeyCol] = 0;
}
}
/*