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Completely remove the iScanRatio field. The PRAGMA index_list(TABLE) command

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shows the estimated row size in the forth column.  It also generates a row
for the table with an index name of NULL.  The query planner still does not
take row size estimates into account - that is the next step.

FossilOrigin-Name: 8b4aa0c7a2122bbe60432edadf27e490e31ec987
This commit is contained in:
drh
2013-10-05 19:18:00 +00:00
parent 0af62b015a
commit e13e9f54b0
8 changed files with 50 additions and 64 deletions
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7
src/where.c
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@@ -4569,7 +4569,7 @@ static int whereLoopAddBtree(
pNew->iSortIdx = b ? iSortIdx : 0;
/* TUNING: Cost of full table scan is 3*(N + log2(N)).
** + The extra 3 factor is to encourage the use of indexed lookups
** over full scans. */
** over full scans. FIXME */
pNew->rRun = sqlite3LogEstAdd(rSize,rLogSize) + 16;
whereLoopOutputAdjust(pWC, pNew, pSrc->iCursor);
rc = whereLoopInsert(pBuilder, pNew);
@@ -4583,7 +4583,6 @@ static int whereLoopAddBtree(
if( b
|| ( m==0
&& pProbe->bUnordered==0
&& pProbe->iScanRatio<128
&& (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0
&& sqlite3GlobalConfig.bUseCis
&& OptimizationEnabled(pWInfo->pParse->db, SQLITE_CoverIdxScan)
@@ -4594,9 +4593,9 @@ static int whereLoopAddBtree(
/* TUNING: Cost of a covering index scan is K*(N + log2(N)).
** + The extra factor K of between 1.1 (iScanRatio between 0
** and 9) and 2.8 (iScanRatio between 126 and 127) is added
** to encourage the use of indexed lookups.
** to encourage the use of indexed lookups. FIXME
*/
pNew->rRun = sqlite3LogEstAdd(rSize,rLogSize) + pProbe->iScanRatio/9 + 1;
pNew->rRun = sqlite3LogEstAdd(rSize,rLogSize) + 10;
}else{
assert( b!=0 );
/* TUNING: Cost of scanning a non-covering index is (N+1)*log2(N)