return SQLITE_OK;
}
+/*
+** Maximum number of tokens a phrase may have to be considered for the
+** incremental doclists strategy.
+*/
+#define MAX_INCR_PHRASE_TOKENS 4
+
/*
** This function is called for each Fts3Phrase in a full-text query
** expression to initialize the mechanism for returning rows. Once this
** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
*/
static int fts3EvalPhraseStart(Fts3Cursor *pCsr, int bOptOk, Fts3Phrase *p){
- int rc; /* Error code */
- Fts3PhraseToken *pFirst = &p->aToken[0];
Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+ int rc = SQLITE_OK; /* Error code */
+ int i;
- if( pCsr->bDesc==pTab->bDescIdx
- && bOptOk==1
- && p->nToken==1
- && pFirst->pSegcsr
- && pFirst->pSegcsr->bLookup
- && pFirst->bFirst==0
- ){
+ /* Determine if doclists may be loaded from disk incrementally. This is
+ ** possible if the bOptOk argument is true, the FTS doclists will be
+ ** scanned in forward order, and the phrase consists of
+ ** MAX_INCR_PHRASE_TOKENS or fewer tokens, none of which are are "^first"
+ ** tokens or prefix tokens that cannot use a prefix-index. */
+ int bIncrOk = (bOptOk
+ && pCsr->bDesc==pTab->bDescIdx
+ && p->nToken<=MAX_INCR_PHRASE_TOKENS && p->nToken>0
+ );
+ for(i=0; bIncrOk==1 && i<p->nToken; i++){
+ Fts3PhraseToken *pToken = &p->aToken[i];
+ if( pToken->bFirst || !pToken->pSegcsr || !pToken->pSegcsr->bLookup ){
+ bIncrOk = 0;
+ }
+ }
+
+ if( bIncrOk ){
/* Use the incremental approach. */
int iCol = (p->iColumn >= pTab->nColumn ? -1 : p->iColumn);
- rc = sqlite3Fts3MsrIncrStart(
- pTab, pFirst->pSegcsr, iCol, pFirst->z, pFirst->n);
- p->bIncr = 1;
-
+ for(i=0; rc==SQLITE_OK && i<p->nToken; i++){
+ Fts3PhraseToken *pTok = &p->aToken[i];
+ rc = sqlite3Fts3MsrIncrStart(pTab, pTok->pSegcsr, iCol, pTok->z, pTok->n);
+ }
}else{
/* Load the full doclist for the phrase into memory. */
rc = fts3EvalPhraseLoad(pCsr, p);
- p->bIncr = 0;
}
+ p->bIncr = bIncrOk;
assert( rc!=SQLITE_OK || p->nToken<1 || p->aToken[0].pSegcsr==0 || p->bIncr );
return rc;
}
/*
-** Attempt to move the phrase iterator to point to the next matching docid.
+** Helper type used by fts3EvalIncrPhraseNext() and incrPhraseTokenNext().
+*/
+typedef struct TokenDoclist TokenDoclist;
+struct TokenDoclist {
+ sqlite3_int64 iDocid;
+ char *pList;
+ int nList;
+};
+
+/*
+** Token pToken is an incrementally loaded token that is part of a
+** multi-token phrase. Advance it to the next matching document in the
+** database and populate output variable *p with the details of the new
+** entry. Or, if the iterator has reached EOF, set *pbEof to true.
+**
** If an error occurs, return an SQLite error code. Otherwise, return
** SQLITE_OK.
+*/
+static int incrPhraseTokenNext(
+ Fts3Table *pTab, /* Virtual table handle */
+ Fts3PhraseToken *pToken, /* Advance the iterator for this token */
+ TokenDoclist *p, /* OUT: Docid and doclist for new entry */
+ int *pbEof /* OUT: True if iterator is at EOF */
+){
+ int rc;
+ assert( pToken->pDeferred==0 );
+ rc = sqlite3Fts3MsrIncrNext(
+ pTab, pToken->pSegcsr, &p->iDocid, &p->pList, &p->nList
+ );
+ if( p->pList==0 ) *pbEof = 1;
+ return rc;
+}
+
+
+/*
+** The phrase iterator passed as the second argument uses the incremental
+** doclist strategy. Advance it to the next matching documnent in the
+** database. If an error occurs, return an SQLite error code. Otherwise,
+** return SQLITE_OK.
**
** If there is no "next" entry and no error occurs, then *pbEof is set to
** 1 before returning. Otherwise, if no error occurs and the iterator is
** successfully advanced, *pbEof is set to 0.
*/
-static int fts3EvalPhraseNext(
+static int fts3EvalIncrPhraseNext(
Fts3Cursor *pCsr, /* FTS Cursor handle */
Fts3Phrase *p, /* Phrase object to advance to next docid */
u8 *pbEof /* OUT: Set to 1 if EOF */
int rc = SQLITE_OK;
Fts3Doclist *pDL = &p->doclist;
Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+ int bEof = 0;
- if( p->bIncr ){
- assert( p->nToken==1 );
- assert( pDL->pNextDocid==0 );
+ assert( p->bIncr==1 );
+ assert( pDL->pNextDocid==0 );
+
+ if( p->nToken==1 ){
rc = sqlite3Fts3MsrIncrNext(pTab, p->aToken[0].pSegcsr,
&pDL->iDocid, &pDL->pList, &pDL->nList
);
- if( rc==SQLITE_OK && !pDL->pList ){
- *pbEof = 1;
+ if( pDL->pList==0 ) bEof = 1;
+ }else{
+ int bDescDoclist = pCsr->bDesc;
+ struct TokenDoclist a[MAX_INCR_PHRASE_TOKENS];
+
+ assert( p->nToken<=MAX_INCR_PHRASE_TOKENS );
+
+ while( bEof==0 ){
+ sqlite3_int64 iMax; /* Largest docid for all iterators */
+ int i; /* Used to iterate through tokens */
+
+ /* Advance the iterator for each token in the phrase once. */
+ for(i=0; rc==SQLITE_OK && i<p->nToken; i++){
+ rc = incrPhraseTokenNext(pTab, &p->aToken[i], &a[i], &bEof);
+ if( i==0 || DOCID_CMP(iMax, a[i].iDocid)<0 ){
+ iMax = a[i].iDocid;
+ }
+ }
+
+ /* Keep advancing iterators until they all point to the same document */
+ if( bEof==0 && rc==SQLITE_OK ){
+ for(i=0; i<p->nToken; i++){
+ while( DOCID_CMP(a[i].iDocid, iMax)<0 && rc==SQLITE_OK && bEof==0 ){
+ rc = incrPhraseTokenNext(pTab, &p->aToken[i], &a[i], &bEof);
+ if( DOCID_CMP(a[i].iDocid, iMax)>0 ){
+ iMax = a[i].iDocid;
+ i = 0;
+ }
+ }
+ }
+ }
+
+ /* Check if the current entries really are a phrase match */
+ if( bEof==0 ){
+ int nByte = a[p->nToken-1].nList;
+ char *aDoclist = sqlite3_malloc(nByte+1);
+ if( !aDoclist ) return SQLITE_NOMEM;
+ memcpy(aDoclist, a[p->nToken-1].pList, nByte+1);
+
+ int nList;
+ for(i=0; i<(p->nToken-1); i++){
+ char *pLeft = a[i].pList;
+ char *pRight = aDoclist;
+ char *pOut = aDoclist;
+ int nDist = p->nToken-1-i;
+ int res = fts3PoslistPhraseMerge(&pOut, nDist, 0, 1, &pLeft, &pRight);
+ if( res==0 ) break;
+ nList = (pOut - aDoclist);
+ }
+ if( i==(p->nToken-1) ){
+ pDL->iDocid = a[0].iDocid;
+ pDL->pList = aDoclist;
+ pDL->nList = nList;
+ pDL->bFreeList = 1;
+ break;
+ }
+ sqlite3_free(aDoclist);
+ }
}
+ }
+
+ *pbEof = bEof;
+ return rc;
+}
+
+/*
+** Attempt to move the phrase iterator to point to the next matching docid.
+** If an error occurs, return an SQLite error code. Otherwise, return
+** SQLITE_OK.
+**
+** If there is no "next" entry and no error occurs, then *pbEof is set to
+** 1 before returning. Otherwise, if no error occurs and the iterator is
+** successfully advanced, *pbEof is set to 0.
+*/
+static int fts3EvalPhraseNext(
+ Fts3Cursor *pCsr, /* FTS Cursor handle */
+ Fts3Phrase *p, /* Phrase object to advance to next docid */
+ u8 *pbEof /* OUT: Set to 1 if EOF */
+){
+ int rc = SQLITE_OK;
+ Fts3Doclist *pDL = &p->doclist;
+ Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+
+ if( p->bIncr ){
+ rc = fts3EvalIncrPhraseNext(pCsr, p, pbEof);
}else if( pCsr->bDesc!=pTab->bDescIdx && pDL->nAll ){
sqlite3Fts3DoclistPrev(pTab->bDescIdx, pDL->aAll, pDL->nAll,
&pDL->pNextDocid, &pDL->iDocid, &pDL->nList, pbEof
static void fts3EvalStartReaders(
Fts3Cursor *pCsr, /* FTS Cursor handle */
Fts3Expr *pExpr, /* Expression to initialize phrases in */
- int bOptOk, /* True to enable incremental loading */
int *pRc /* IN/OUT: Error code */
){
if( pExpr && SQLITE_OK==*pRc ){
if( pExpr->pPhrase->aToken[i].pDeferred==0 ) break;
}
pExpr->bDeferred = (i==nToken);
- *pRc = fts3EvalPhraseStart(pCsr, bOptOk, pExpr->pPhrase);
+ *pRc = fts3EvalPhraseStart(pCsr, 1, pExpr->pPhrase);
}else{
- fts3EvalStartReaders(pCsr, pExpr->pLeft, bOptOk, pRc);
- fts3EvalStartReaders(pCsr, pExpr->pRight, bOptOk, pRc);
+ fts3EvalStartReaders(pCsr, pExpr->pLeft, pRc);
+ fts3EvalStartReaders(pCsr, pExpr->pRight, pRc);
pExpr->bDeferred = (pExpr->pLeft->bDeferred && pExpr->pRight->bDeferred);
}
}
}
#endif
- fts3EvalStartReaders(pCsr, pCsr->pExpr, 1, &rc);
+ fts3EvalStartReaders(pCsr, pCsr->pExpr, &rc);
return rc;
}
if( pPhrase ){
fts3EvalInvalidatePoslist(pPhrase);
if( pPhrase->bIncr ){
- assert( pPhrase->nToken==1 );
- assert( pPhrase->aToken[0].pSegcsr );
- sqlite3Fts3MsrIncrRestart(pPhrase->aToken[0].pSegcsr);
+ int i;
+ for(i=0; i<pPhrase->nToken; i++){
+ assert( pPhrase->aToken[i].pSegcsr );
+ sqlite3Fts3MsrIncrRestart(pPhrase->aToken[i].pSegcsr);
+ }
*pRc = fts3EvalPhraseStart(pCsr, 0, pPhrase);
}
-
pPhrase->doclist.pNextDocid = 0;
pPhrase->doclist.iDocid = 0;
}
projects / thirdparty / sqlite.git / commitdiff
