Do not fallback to AND for FTS phrase operator.

If there is no positional information of lexemes then phrase operator will not
fallback to AND operator. This change makes needing to modify TS_execute()
interface, because somewhere (in indexes, for example) positional information
is unaccesible and in this cases we need to force fallback to AND.

Per discussion c19fcfec308e6ccd952cdde9e648b505@mail.gmail.com

1 files changed, 19 insertions, 16 deletions

diff --git a/src/backend/utils/adt/tsvector_op.c b/src/backend/utils/adt/tsvector_op.c
index 04718829a0b..242b7e137b7 100644
--- a/src/backend/utils/adt/tsvector_op.c
+++ b/src/backend/utils/adt/tsvector_op.c
@@ -1360,7 +1360,7 @@ checkcondition_str(void *checkval, QueryOperand *val, ExecPhraseData *data)
  */
 static bool
 TS_phrase_execute(QueryItem *curitem,
-				  void *checkval, bool calcnot, ExecPhraseData *data,
+				  void *checkval, uint32 flags, ExecPhraseData *data,
 				  bool (*chkcond) (void *, QueryOperand *, ExecPhraseData *))
 {
 	/* since this function recurses, it could be driven to stack overflow */
@@ -1382,18 +1382,19 @@ TS_phrase_execute(QueryItem *curitem,
 		Assert(curitem->qoperator.oper == OP_PHRASE);
 
 		if (!TS_phrase_execute(curitem + curitem->qoperator.left,
-							   checkval, calcnot, &Ldata, chkcond))
+							   checkval, flags, &Ldata, chkcond))
 			return false;
 
-		if (!TS_phrase_execute(curitem + 1, checkval, calcnot, &Rdata, chkcond))
+		if (!TS_phrase_execute(curitem + 1, checkval, flags, &Rdata, chkcond))
 			return false;
 
 		/*
 		 * if at least one of the operands has no position information,
-		 * fallback to AND operation.
+		 * then return false. But if TS_EXEC_PHRASE_AS_AND flag is set then
+		 * we return true as it is a AND operation
 		 */
 		if (Ldata.npos == 0 || Rdata.npos == 0)
-			return true;
+			return (flags & TS_EXEC_PHRASE_AS_AND) ? true : false;
 
 		/*
 		 * Result of the operation is a list of the corresponding positions of
@@ -1498,13 +1499,11 @@ TS_phrase_execute(QueryItem *curitem,
  * chkcond is a callback function used to evaluate each VAL node in the query.
  * checkval can be used to pass information to the callback. TS_execute doesn't
  * do anything with it.
- * if calcnot is false, NOT expressions are always evaluated to be true. This
- * is used in ranking.
  * It believes that ordinary operators are always closier to root than phrase
  * operator, so, TS_execute() may not take care of lexeme's position at all.
  */
 bool
-TS_execute(QueryItem *curitem, void *checkval, bool calcnot,
+TS_execute(QueryItem *curitem, void *checkval, uint32 flags,
    bool (*chkcond) (void *checkval, QueryOperand *val, ExecPhraseData *data))
 {
 	/* since this function recurses, it could be driven to stack overflow */
@@ -1517,25 +1516,29 @@ TS_execute(QueryItem *curitem, void *checkval, bool calcnot,
 	switch (curitem->qoperator.oper)
 	{
 		case OP_NOT:
-			if (calcnot)
-				return !TS_execute(curitem + 1, checkval, calcnot, chkcond);
+			if (flags & TS_EXEC_CALC_NOT)
+				return !TS_execute(curitem + 1, checkval, flags, chkcond);
 			else
 				return true;
 
 		case OP_AND:
-			if (TS_execute(curitem + curitem->qoperator.left, checkval, calcnot, chkcond))
-				return TS_execute(curitem + 1, checkval, calcnot, chkcond);
+			if (TS_execute(curitem + curitem->qoperator.left, checkval, flags, chkcond))
+				return TS_execute(curitem + 1, checkval, flags, chkcond);
 			else
 				return false;
 
 		case OP_OR:
-			if (TS_execute(curitem + curitem->qoperator.left, checkval, calcnot, chkcond))
+			if (TS_execute(curitem + curitem->qoperator.left, checkval, flags, chkcond))
 				return true;
 			else
-				return TS_execute(curitem + 1, checkval, calcnot, chkcond);
+				return TS_execute(curitem + 1, checkval, flags, chkcond);
 
 		case OP_PHRASE:
-			return TS_phrase_execute(curitem, checkval, calcnot, NULL, chkcond);
+			/*
+			 * do not check TS_EXEC_PHRASE_AS_AND here because chkcond()
+			 * could do something more if it's called from TS_phrase_execute()
+			 */
+			return TS_phrase_execute(curitem, checkval, flags, NULL, chkcond);
 
 		default:
 			elog(ERROR, "unrecognized operator: %d", curitem->qoperator.oper);
@@ -1633,7 +1636,7 @@ ts_match_vq(PG_FUNCTION_ARGS)
 	result = TS_execute(
 						GETQUERY(query),
 						&chkval,
-						true,
+						TS_EXEC_CALC_NOT,
 						checkcondition_str
 		);