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Simplify the code used to generate the text for EXPLAIN QUERY PLAN.

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FossilOrigin-Name: beea1efc3a49cad08087fcbb18dbce71c873fe57
This commit is contained in:
drh
2014-10-10 15:47:46 +00:00
parent 681fca0018
commit 6c97789d2e
3 changed files with 57 additions and 57 deletions
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100
src/where.c
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@@ -2737,9 +2737,8 @@ static void explainAppendTerm(
/*
** Argument pLevel describes a strategy for scanning table pTab. This
** function returns a pointer to a string buffer containing a description
** of the subset of table rows scanned by the strategy in the form of an
** SQL expression. Or, if all rows are scanned, NULL is returned.
** function appends text to pStr that describes the subset of table
** rows scanned by the strategy in the form of an SQL expression.
**
** For example, if the query:
**
@@ -2749,49 +2748,37 @@ static void explainAppendTerm(
** string similar to:
**
** "a=? AND b>?"
**
** The returned pointer points to memory obtained from sqlite3DbMalloc().
** It is the responsibility of the caller to free the buffer when it is
** no longer required.
*/
static char *explainIndexRange(sqlite3 *db, WhereLoop *pLoop, Table *pTab){
void explainIndexRange(StrAccum *pStr, WhereLoop *pLoop, Table *pTab){
Index *pIndex = pLoop->u.btree.pIndex;
u16 nEq = pLoop->u.btree.nEq;
u16 nSkip = pLoop->u.btree.nSkip;
int i, j;
Column *aCol = pTab->aCol;
i16 *aiColumn = pIndex->aiColumn;
StrAccum txt;
if( nEq==0 && (pLoop->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ){
return 0;
}
sqlite3StrAccumInit(&txt, 0, 0, SQLITE_MAX_LENGTH);
txt.db = db;
sqlite3StrAccumAppend(&txt, " (", 2);
if( nEq==0 && (pLoop->wsFlags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ) return;
sqlite3StrAccumAppend(pStr, " (", 2);
for(i=0; i<nEq; i++){
char *z = aiColumn[i] < 0 ? "rowid" : aCol[aiColumn[i]].zName;
if( i>=nSkip ){
explainAppendTerm(&txt, i, z, "=");
explainAppendTerm(pStr, i, z, "=");
}else{
if( i ) sqlite3StrAccumAppend(&txt, " AND ", 5);
sqlite3StrAccumAppend(&txt, "ANY(", 4);
sqlite3StrAccumAppendAll(&txt, z);
sqlite3StrAccumAppend(&txt, ")", 1);
if( i ) sqlite3StrAccumAppend(pStr, " AND ", 5);
sqlite3XPrintf(pStr, 0, "ANY(%s)", z);
}
}
j = i;
if( pLoop->wsFlags&WHERE_BTM_LIMIT ){
char *z = aiColumn[j] < 0 ? "rowid" : aCol[aiColumn[j]].zName;
explainAppendTerm(&txt, i++, z, ">");
explainAppendTerm(pStr, i++, z, ">");
}
if( pLoop->wsFlags&WHERE_TOP_LIMIT ){
char *z = aiColumn[j] < 0 ? "rowid" : aCol[aiColumn[j]].zName;
explainAppendTerm(&txt, i, z, "<");
explainAppendTerm(pStr, i, z, "<");
}
sqlite3StrAccumAppend(&txt, ")", 1);
return sqlite3StrAccumFinish(&txt);
sqlite3StrAccumAppend(pStr, ")", 1);
}
/*
@@ -2815,11 +2802,13 @@ static void explainOneScan(
struct SrcList_item *pItem = &pTabList->a[pLevel->iFrom];
Vdbe *v = pParse->pVdbe; /* VM being constructed */
sqlite3 *db = pParse->db; /* Database handle */
char *zMsg; /* Text to add to EQP output */
int iId = pParse->iSelectId; /* Select id (left-most output column) */
int isSearch; /* True for a SEARCH. False for SCAN. */
WhereLoop *pLoop; /* The controlling WhereLoop object */
u32 flags; /* Flags that describe this loop */
char *zMsg; /* Text to add to EQP output */
StrAccum str; /* EQP output string */
char zBuf[100]; /* Initial space for EQP output string */
pLoop = pLevel->pWLoop;
flags = pLoop->wsFlags;
@@ -2829,54 +2818,65 @@ static void explainOneScan(
|| ((flags&WHERE_VIRTUALTABLE)==0 && (pLoop->u.btree.nEq>0))
|| (wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX));
zMsg = sqlite3MPrintf(db, "%s", isSearch?"SEARCH":"SCAN");
sqlite3StrAccumInit(&str, zBuf, sizeof(zBuf), SQLITE_MAX_LENGTH);
str.db = db;
sqlite3StrAccumAppendAll(&str, isSearch ? "SEARCH" : "SCAN");
if( pItem->pSelect ){
zMsg = sqlite3MAppendf(db, zMsg, "%s SUBQUERY %d", zMsg,pItem->iSelectId);
sqlite3XPrintf(&str, 0, " SUBQUERY %d", pItem->iSelectId);
}else{
zMsg = sqlite3MAppendf(db, zMsg, "%s TABLE %s", zMsg, pItem->zName);
sqlite3XPrintf(&str, 0, " TABLE %s", pItem->zName);
}
if( pItem->zAlias ){
zMsg = sqlite3MAppendf(db, zMsg, "%s AS %s", zMsg, pItem->zAlias);
sqlite3XPrintf(&str, 0, " AS %s", pItem->zAlias);
}
if( (flags & (WHERE_IPK|WHERE_VIRTUALTABLE))==0
&& ALWAYS(pLoop->u.btree.pIndex!=0)
){
const char *zFmt;
Index *pIdx = pLoop->u.btree.pIndex;
char *zWhere = explainIndexRange(db, pLoop, pItem->pTab);
if( (flags & (WHERE_IPK|WHERE_VIRTUALTABLE))==0 ){
const char *zFmt = 0;
Index *pIdx;
assert( pLoop->u.btree.pIndex!=0 );
pIdx = pLoop->u.btree.pIndex;
assert( !(flags&WHERE_AUTO_INDEX) || (flags&WHERE_IDX_ONLY) );
if( !HasRowid(pItem->pTab) && IsPrimaryKeyIndex(pIdx) ){
zFmt = zWhere ? "%s USING PRIMARY KEY%.0s%s" : "%s%.0s%s";
if( pLoop->u.btree.nEq>0
|| (pLoop->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0
){
zFmt = "PRIMARY KEY";
}
}else if( flags & WHERE_AUTO_INDEX ){
zFmt = "%s USING AUTOMATIC COVERING INDEX%.0s%s";
zFmt = "AUTOMATIC COVERING INDEX";
}else if( flags & WHERE_IDX_ONLY ){
zFmt = "%s USING COVERING INDEX %s%s";
zFmt = "COVERING INDEX %s";
}else{
zFmt = "%s USING INDEX %s%s";
zFmt = "INDEX %s";
}
if( zFmt ){
sqlite3StrAccumAppend(&str, " USING ", 7);
sqlite3XPrintf(&str, 0, zFmt, pIdx->zName);
explainIndexRange(&str, pLoop, pItem->pTab);
}
zMsg = sqlite3MAppendf(db, zMsg, zFmt, zMsg, pIdx->zName, zWhere);
sqlite3DbFree(db, zWhere);
}else if( (flags & WHERE_IPK)!=0 && (flags & WHERE_CONSTRAINT)!=0 ){
zMsg = sqlite3MAppendf(db, zMsg, "%s USING INTEGER PRIMARY KEY", zMsg);
const char *zRange;
if( flags&(WHERE_COLUMN_EQ|WHERE_COLUMN_IN) ){
zMsg = sqlite3MAppendf(db, zMsg, "%s (rowid=?)", zMsg);
zRange = "(rowid=?)";
}else if( (flags&WHERE_BOTH_LIMIT)==WHERE_BOTH_LIMIT ){
zMsg = sqlite3MAppendf(db, zMsg, "%s (rowid>? AND rowid<?)", zMsg);
zRange = "(rowid>? AND rowid<?)";
}else if( flags&WHERE_BTM_LIMIT ){
zMsg = sqlite3MAppendf(db, zMsg, "%s (rowid>?)", zMsg);
}else if( ALWAYS(flags&WHERE_TOP_LIMIT) ){
zMsg = sqlite3MAppendf(db, zMsg, "%s (rowid<?)", zMsg);
zRange = "(rowid>?)";
}else{
assert( flags&WHERE_TOP_LIMIT);
zRange = "(rowid<?)";
}
sqlite3StrAccumAppendAll(&str, " USING INTEGER PRIMARY KEY ");
sqlite3StrAccumAppendAll(&str, zRange);
}
#ifndef SQLITE_OMIT_VIRTUALTABLE
else if( (flags & WHERE_VIRTUALTABLE)!=0 ){
zMsg = sqlite3MAppendf(db, zMsg, "%s VIRTUAL TABLE INDEX %d:%s", zMsg,
sqlite3XPrintf(&str, 0, " VIRTUAL TABLE INDEX %d:%s",
pLoop->u.vtab.idxNum, pLoop->u.vtab.idxStr);
}
#endif
zMsg = sqlite3MAppendf(db, zMsg, "%s", zMsg);
zMsg = sqlite3StrAccumFinish(&str);
sqlite3VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, zMsg, P4_DYNAMIC);
}
}