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More work on the new optimizer. Fewer tests fail now. (CVS 2565)

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FossilOrigin-Name: ee3a08e353f563c36e904479393fcb56f96ee975
This commit is contained in:
drh
2005-07-27 20:41:43 +00:00
parent 51147baa6d
commit 28c4cf42da
4 changed files with 124 additions and 45 deletions
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14
manifest
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@@ -1,5 +1,5 @@
C A\snew\soptimizer\sthat\sbreaks\sa\slot\sof\stests.\s\sBut\snone\sof\sthem\scritically,\sI\nthink.\s\sNevertheless,\sthere\sis\sa\slot\sof\swork\sahead\sto\sstabilize\sthe\scode.\s(CVS\s2564)
D 2005-07-23T22:59:56
C More\swork\son\sthe\snew\soptimizer.\s\sFewer\stests\sfail\snow.\s(CVS\s2565)
D 2005-07-27T20:41:44
F Makefile.in 22ea9c0fe748f591712d8fe3c6d972c6c173a165
F Makefile.linux-gcc 06be33b2a9ad4f005a5f42b22c4a19dab3cbb5c7
F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
@@ -33,7 +33,7 @@ F src/attach.c 3615dbe960cbee4aa5ea300b8a213dad36527b0f
F src/auth.c 18c5a0befe20f3a58a41e3ddd78f372faeeefe1f
F src/btree.c ec55bd70052cdd0958f3a0e79ad58d93561acb20
F src/btree.h 41a71ce027db9ddee72cb43df2316bbe3a1d92af
F src/build.c b78e95dcfcbbe285969e9563560f3e20a23cc8c0
F src/build.c 4b6f9e61159733f86cd1589f4c10834ba856d280
F src/callback.c 0910b611e0c158f107ee3ff86f8a371654971e2b
F src/date.c 7444b0900a28da77e57e3337a636873cff0ae940
F src/delete.c be1fc25c9e109cd8cbab42a43ee696263da7c04b
@@ -85,7 +85,7 @@ F src/vdbeapi.c 7f392f0792d1258c958083d7de9eae7c3530c9a6
F src/vdbeaux.c 3732a86566a6be4da4c606e9334baf3fd98667af
F src/vdbefifo.c b8805850afe13b43f1de78d58088cb5d66f88e1e
F src/vdbemem.c da8e8d6f29dd1323f782f000d7cd120027c9ff03
F src/where.c 3e9f8336bac3bbc829b85381227f1341f3fd4362
F src/where.c 7757b1731d74364bc56d7da7cb9cfe8c9db1c019
F tclinstaller.tcl 046e3624671962dc50f0481d7c25b38ef803eb42
F test/all.test 7f0988442ab811dfa41793b5b550f5828ce316f3
F test/alter.test 9d6837a3d946b73df692b7cef2a7644d2e2f6bc6
@@ -287,7 +287,7 @@ F www/tclsqlite.tcl 425be741b8ae664f55cb1ef2371aab0a75109cf9
F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
F www/version3.tcl a99cf5f6d8bd4d5537584a2b342f0fb9fa601d8b
F www/whentouse.tcl 528299b8316726dbcc5548e9aa0648c8b1bd055b
P 868279c78e056d27b2d1bea81127fe689b2ce478
R 5bb82d998a20777c2205e35147889290
P 86ce56ccea8297b1fba2b9ee53b5f1a3f228662f
R 4972a6e268e2ac2613a7a3e2ab4d4526
U drh
Z 9d14e39e2e0ab0d8adb6f266b567831d
Z 231d7effe54ec2e53a7f03147246d17a

2
manifest.uuid
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@@ -1 +1 @@
86ce56ccea8297b1fba2b9ee53b5f1a3f228662f
ee3a08e353f563c36e904479393fcb56f96ee975

46
src/build.c
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@@ -22,7 +22,7 @@
** COMMIT
** ROLLBACK
**
** $Id: build.c,v 1.336 2005/07/23 22:59:56 drh Exp $
** $Id: build.c,v 1.337 2005/07/27 20:41:44 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
@@ -2390,15 +2390,47 @@ exit_create_index:
/*
** Fill the Index.aiRowEst[] array with default information - information
** to be used when we have no ANALYZE command to run.
**
** aiRowEst[0] is suppose to contain the number of elements in the 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 the index. And so forth. It must always be the case that
*
** aiRowEst[N]<=aiRowEst[N-1]
** aiRowEst[N]>=1
**
** Apart from that, we have little to go on besides intuition as to
** how aiRowEst[] should be initialized. The numbers generated here
** are based on typical values found in actual indices.
*/
void sqlite3DefaultRowEst(Index *pIdx){
int *a = pIdx->aiRowEst;
int i;
int n = pIdx->nColumn;
int j = 1000000;
int f = (1000000-1-100*(pIdx->onError==OE_None))/n;
for(i=0; i<=n; i++, j-=f){
assert( j>0 );
pIdx->aiRowEst[i] = j;
assert( a!=0 );
a[0] = 1000000;
switch( pIdx->nColumn ){
case 1: {
a[1] = 20;
break;
}
case 2: {
a[1] = 350;
a[2] = 20;
break;
}
default: {
a[1] = 1250;
a[2] = 350;
a[3] = 20;
for(i=pIdx->nColumn; i>=4; i--){
a[i] = 10;
}
}
}
if( pIdx->onError!=OE_None ){
a[pIdx->nColumn] = 1;
}
}

107
src/where.c
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@@ -16,7 +16,7 @@
** so is applicable. Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.152 2005/07/23 22:59:56 drh Exp $
** $Id: where.c,v 1.153 2005/07/27 20:41:44 drh Exp $
*/
#include "sqliteInt.h"
@@ -544,6 +544,14 @@ static int isSortingIndex(
nTerm = pOrderBy->nExpr;
assert( nTerm>0 );
/* A UNIQUE index that is fully specified is always a sorting
** index.
*/
if( pIdx->onError!=OE_None && nEqCol==pIdx->nColumn ){
*pbRev = 0;
return 1;
}
/* Match terms of the ORDER BY clause against columns of
** the index.
*/
@@ -619,6 +627,25 @@ static int sortableByRowid(
return 0;
}
/*
** Prepare a crude estimate of the logorithm of the input value.
** The results need not be exact. This is only used for estimating
** the total cost of performing operatings with O(logN) or O(NlogN)
** complexity. Because N is just a guess, it is no great tragedy if
** logN is a little off.
**
** We can assume N>=1.0;
*/
static double estLog(double N){
double logN = 1.0;
double x = 10.0;
while( N>x ){
logN = logN+1.0;
x *= 10;
}
return logN;
}
/*
** Find the best index for accessing a particular table. Return a pointer
** to the index, flags that describe how the index should be used, the
@@ -668,46 +695,64 @@ static double bestIndex(
*ppIndex = 0;
bestFlags = WHERE_ROWID_EQ;
if( pTerm->operator & WO_EQ ){
/* Rowid== is always the best pick. Look no further. Because only
** a single row is generated, output is always in sorted order */
*pFlags = WHERE_ROWID_EQ;
*pnEq = 1;
if( pOrderBy ) *pFlags |= WHERE_ORDERBY;
TRACE(("... best is rowid\n"));
return 0.0;
}else if( pTerm->operator & WO_LIST ){
/* Rowid IN (LIST): cost is NlogN where N is the number of list
** elements. */
lowestCost = pTerm->pExpr->pList->nExpr;
lowestCost *= estLog(lowestCost);
}else{
lowestCost = 100.0;
/* Rowid IN (SELECT): cost is NlogN where N is the number of rows
** in the result of the inner select. We have no way to estimate
** that value so make a wild guess. */
lowestCost = 200.0;
}
TRACE(("... rowid IN cost: %g\n", lowestCost));
}
/* Check for constraints on a range of rowids or a full table scan.
/* Estimate the cost of a table scan. If we do not know how many
** entries are in the table, use 1 million as a guess.
*/
pProbe = pSrc->pTab->pIndex;
cost = pProbe ? pProbe->aiRowEst[0] : 100000.0;
TRACE(("... base cost: %g\n", cost));
cost = pProbe ? pProbe->aiRowEst[0] : 1000000.0;
TRACE(("... table scan base cost: %g\n", cost));
flags = WHERE_ROWID_RANGE;
/* Check for constraints on a range of rowids in a table scan.
*/
pTerm = findTerm(pWC, iCur, -1, notReady, WO_LT|WO_LE|WO_GT|WO_GE, 0);
if( pTerm ){
flags = WHERE_ROWID_RANGE;
if( findTerm(pWC, iCur, -1, notReady, WO_LT|WO_LE, 0) ){
flags |= WHERE_TOP_LIMIT;
cost *= 0.25; /* Guess that rowid<EXPR eliminates 75% of the search */
cost *= 0.333; /* Guess that rowid<EXPR eliminates two-thirds or rows */
}
if( findTerm(pWC, iCur, -1, notReady, WO_GT|WO_GE, 0) ){
flags |= WHERE_BTM_LIMIT;
cost *= 0.25; /* Guess that rowid>EXPR eliminates 75% of the search */
cost *= 0.333; /* Guess that rowid>EXPR eliminates two-thirds of rows */
}
TRACE(("... rowid range cost: %g\n", cost));
TRACE(("... rowid range reduces cost to %g\n", cost));
}else{
flags = 0;
}
if( pOrderBy && sortableByRowid(iCur, pOrderBy, &rev) ){
flags |= WHERE_ORDERBY|WHERE_ROWID_RANGE;
cost *= 0.5;
if( rev ){
flags |= WHERE_REVERSE;
/* If the table scan does not satisfy the ORDER BY clause, increase
** the cost by NlogN to cover the expense of sorting. */
if( pOrderBy ){
if( sortableByRowid(iCur, pOrderBy, &rev) ){
flags |= WHERE_ORDERBY|WHERE_ROWID_RANGE;
if( rev ){
flags |= WHERE_REVERSE;
}
}else{
cost += cost*estLog(cost);
TRACE(("... sorting increases cost to %g\n", cost));
}
TRACE(("... order by reduces cost to %g\n", cost));
}
if( cost<lowestCost ){
lowestCost = cost;
@@ -718,7 +763,7 @@ static double bestIndex(
*/
for(; pProbe; pProbe=pProbe->pNext){
int i; /* Loop counter */
double inMultiplier = 2.0; /* Includes built-in index lookup penalty */
double inMultiplier = 1.0;
TRACE(("... index %s:\n", pProbe->zName));
@@ -740,7 +785,7 @@ static double bestIndex(
}
}
}
cost = pProbe->aiRowEst[i] * inMultiplier;
cost = pProbe->aiRowEst[i] * inMultiplier * estLog(inMultiplier);
nEq = i;
TRACE(("...... nEq=%d inMult=%g cost=%g\n", nEq, inMultiplier, cost));
@@ -753,30 +798,32 @@ static double bestIndex(
flags = WHERE_COLUMN_RANGE;
if( findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE, pProbe) ){
flags |= WHERE_TOP_LIMIT;
cost *= 0.5;
cost *= 0.333;
}
if( findTerm(pWC, iCur, j, notReady, WO_GT|WO_GE, pProbe) ){
flags |= WHERE_BTM_LIMIT;
cost *= 0.5;
cost *= 0.333;
}
TRACE(("...... range reduces cost to %g\n", cost));
}
}
/* Reduce the cost substantially if this index can be used to satisfy
** the ORDER BY clause
/* Add the additional cost of sorting if that is a factor.
*/
if( pOrderBy && (flags & WHERE_COLUMN_IN)==0 &&
if( pOrderBy ){
if( (flags & WHERE_COLUMN_IN)==0 &&
isSortingIndex(pParse, pProbe, pSrc->pTab, iCur, pOrderBy, nEq, &rev) ){
if( flags==0 ){
flags = WHERE_COLUMN_RANGE;
if( flags==0 ){
flags = WHERE_COLUMN_RANGE;
}
flags |= WHERE_ORDERBY;
if( rev ){
flags |= WHERE_REVERSE;
}
}else{
cost += cost*estLog(cost);
TRACE(("...... orderby reduces cost to %g\n", cost));
}
flags |= WHERE_ORDERBY;
cost *= 0.5;
if( rev ){
flags |= WHERE_REVERSE;
}
TRACE(("...... orderby reduces cost to %g\n", cost));
}
/* Check to see if we can get away with using just the index without