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mirror of https://github.com/sqlite/sqlite.git synced 2025-08-08 14:02:16 +03:00

Background work for experiments trying to enhance ANALYZE so that it runs

off of samples of the entire index and does not need to read the entire
index.

FossilOrigin-Name: 29d1cc5c3619a88229f18c3c8131228f8a2d151ac3d9203f0c7fc538a996ecec
This commit is contained in:
drh
2020-03-10 01:24:13 +00:00
parent afa1ecac9b
commit 9d33d9e7ac
3 changed files with 61 additions and 46 deletions

View File

@@ -188,6 +188,11 @@ static void openStatTable(
Vdbe *v = sqlite3GetVdbe(pParse);
int aRoot[ArraySize(aTable)];
u8 aCreateTbl[ArraySize(aTable)];
#ifdef SQLITE_ENABLE_STAT4
const int nToOpen = OptimizationEnabled(db,SQLITE_Stat4) ? 2 : 1;
#else
const int nToOpen = 1;
#endif
if( v==0 ) return;
assert( sqlite3BtreeHoldsAllMutexes(db) );
@@ -200,8 +205,9 @@ static void openStatTable(
for(i=0; i<ArraySize(aTable); i++){
const char *zTab = aTable[i].zName;
Table *pStat;
aCreateTbl[i] = 0;
if( (pStat = sqlite3FindTable(db, zTab, pDb->zDbSName))==0 ){
if( aTable[i].zCols ){
if( i<nToOpen ){
/* The sqlite_statN table does not exist. Create it. Note that a
** side-effect of the CREATE TABLE statement is to leave the rootpage
** of the new table in register pParse->regRoot. This is important
@@ -217,7 +223,6 @@ static void openStatTable(
** associated with the table zWhere. If zWhere is NULL, delete the
** entire contents of the table. */
aRoot[i] = pStat->tnum;
aCreateTbl[i] = 0;
sqlite3TableLock(pParse, iDb, aRoot[i], 1, zTab);
if( zWhere ){
sqlite3NestedParse(pParse,
@@ -236,7 +241,7 @@ static void openStatTable(
}
/* Open the sqlite_stat[134] tables for writing. */
for(i=0; aTable[i].zCols; i++){
for(i=0; i<nToOpen; i++){
assert( i<ArraySize(aTable) );
sqlite3VdbeAddOp4Int(v, OP_OpenWrite, iStatCur+i, aRoot[i], iDb, 3);
sqlite3VdbeChangeP5(v, aCreateTbl[i]);
@@ -357,10 +362,12 @@ static void sampleCopy(StatAccum *p, StatSample *pTo, StatSample *pFrom){
static void statAccumDestructor(void *pOld){
StatAccum *p = (StatAccum*)pOld;
#ifdef SQLITE_ENABLE_STAT4
int i;
for(i=0; i<p->nCol; i++) sampleClear(p->db, p->aBest+i);
for(i=0; i<p->mxSample; i++) sampleClear(p->db, p->a+i);
sampleClear(p->db, &p->current);
if( p->mxSample ){
int i;
for(i=0; i<p->nCol; i++) sampleClear(p->db, p->aBest+i);
for(i=0; i<p->mxSample; i++) sampleClear(p->db, p->a+i);
sampleClear(p->db, &p->current);
}
#endif
sqlite3DbFree(p->db, p);
}
@@ -400,7 +407,7 @@ static void statInit(
int n; /* Bytes of space to allocate */
sqlite3 *db; /* Database connection */
#ifdef SQLITE_ENABLE_STAT4
int mxSample = SQLITE_STAT4_SAMPLES;
int mxSample = sqlite3_value_int(argv[2]) ? SQLITE_STAT4_SAMPLES : 0;
#endif
/* Decode the three function arguments */
@@ -437,7 +444,7 @@ static void statInit(
p->current.anEq = &p->current.anDLt[nColUp];
#ifdef SQLITE_ENABLE_STAT4
{
if( mxSample ){
u8 *pSpace; /* Allocated space not yet assigned */
int i; /* Used to iterate through p->aSample[] */
@@ -704,7 +711,7 @@ static void statPush(
}else{
/* Second and subsequent calls get processed here */
#ifdef SQLITE_ENABLE_STAT4
samplePushPrevious(p, iChng);
if( p->mxSample ) samplePushPrevious(p, iChng);
#endif
/* Update anDLt[], anLt[] and anEq[] to reflect the values that apply
@@ -715,26 +722,24 @@ static void statPush(
for(i=iChng; i<p->nCol; i++){
p->current.anDLt[i]++;
#ifdef SQLITE_ENABLE_STAT4
p->current.anLt[i] += p->current.anEq[i];
if( p->mxSample ) p->current.anLt[i] += p->current.anEq[i];
#endif
p->current.anEq[i] = 1;
}
}
p->nRow++;
#ifdef SQLITE_ENABLE_STAT4
if( sqlite3_value_type(argv[2])==SQLITE_INTEGER ){
sampleSetRowidInt64(p->db, &p->current, sqlite3_value_int64(argv[2]));
}else{
sampleSetRowid(p->db, &p->current, sqlite3_value_bytes(argv[2]),
sqlite3_value_blob(argv[2]));
}
p->current.iHash = p->iPrn = p->iPrn*1103515245 + 12345;
#endif
#ifdef SQLITE_ENABLE_STAT4
{
tRowcnt nLt = p->current.anLt[p->nCol-1];
if( p->mxSample ){
tRowcnt nLt;
if( sqlite3_value_type(argv[2])==SQLITE_INTEGER ){
sampleSetRowidInt64(p->db, &p->current, sqlite3_value_int64(argv[2]));
}else{
sampleSetRowid(p->db, &p->current, sqlite3_value_bytes(argv[2]),
sqlite3_value_blob(argv[2]));
}
p->current.iHash = p->iPrn = p->iPrn*1103515245 + 12345;
nLt = p->current.anLt[p->nCol-1];
/* Check if this is to be a periodic sample. If so, add it. */
if( (nLt/p->nPSample)!=(nLt+1)/p->nPSample ){
p->current.isPSample = 1;
@@ -804,6 +809,7 @@ static void statGet(
|| eCall==STAT_GET_ROWID || eCall==STAT_GET_NLT
|| eCall==STAT_GET_NDLT
);
assert( eCall==STAT_GET_STAT1 || p->mxSample );
if( eCall==STAT_GET_STAT1 )
#else
assert( argc==1 );
@@ -1089,7 +1095,11 @@ static void analyzeOneTable(
** The third argument is only used for STAT4
*/
#ifdef SQLITE_ENABLE_STAT4
sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regStat4+3);
if( OptimizationEnabled(db, SQLITE_Stat4) ){
sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regStat4+3);
}else{
sqlite3VdbeAddOp2(v, OP_Integer, 0, regStat4+3);
}
#endif
sqlite3VdbeAddOp2(v, OP_Integer, nCol, regStat4+1);
sqlite3VdbeAddOp2(v, OP_Integer, pIdx->nKeyCol, regStat4+2);
@@ -1171,21 +1181,23 @@ static void analyzeOneTable(
** if !eof(csr) goto next_row;
*/
#ifdef SQLITE_ENABLE_STAT4
assert( regRowid==(regStat4+2) );
if( HasRowid(pTab) ){
sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur, regRowid);
}else{
Index *pPk = sqlite3PrimaryKeyIndex(pIdx->pTable);
int j, k, regKey;
regKey = sqlite3GetTempRange(pParse, pPk->nKeyCol);
for(j=0; j<pPk->nKeyCol; j++){
k = sqlite3TableColumnToIndex(pIdx, pPk->aiColumn[j]);
assert( k>=0 && k<pIdx->nColumn );
sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, k, regKey+j);
VdbeComment((v, "%s", pTab->aCol[pPk->aiColumn[j]].zName));
if( OptimizationEnabled(db, SQLITE_Stat4) ){
assert( regRowid==(regStat4+2) );
if( HasRowid(pTab) ){
sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur, regRowid);
}else{
Index *pPk = sqlite3PrimaryKeyIndex(pIdx->pTable);
int j, k, regKey;
regKey = sqlite3GetTempRange(pParse, pPk->nKeyCol);
for(j=0; j<pPk->nKeyCol; j++){
k = sqlite3TableColumnToIndex(pIdx, pPk->aiColumn[j]);
assert( k>=0 && k<pIdx->nColumn );
sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, k, regKey+j);
VdbeComment((v, "%s", pTab->aCol[pPk->aiColumn[j]].zName));
}
sqlite3VdbeAddOp3(v, OP_MakeRecord, regKey, pPk->nKeyCol, regRowid);
sqlite3ReleaseTempRange(pParse, regKey, pPk->nKeyCol);
}
sqlite3VdbeAddOp3(v, OP_MakeRecord, regKey, pPk->nKeyCol, regRowid);
sqlite3ReleaseTempRange(pParse, regKey, pPk->nKeyCol);
}
#endif
assert( regChng==(regStat4+1) );
@@ -1206,7 +1218,7 @@ static void analyzeOneTable(
/* Add the entries to the stat4 table. */
#ifdef SQLITE_ENABLE_STAT4
{
if( OptimizationEnabled(db, SQLITE_Stat4) ){
int regEq = regStat1;
int regLt = regStat1+1;
int regDLt = regStat1+2;