Phrase full text search.

Patch introduces new text search operator (<-> or <DISTANCE>) into tsquery.
On-disk and binary in/out format of tsquery are backward compatible.
It has two side effect:
- change order for tsquery, so, users, who has a btree index over tsquery,
  should reindex it
- less number of parenthesis in tsquery output, and tsquery becomes more
  readable

Authors: Teodor Sigaev, Oleg Bartunov, Dmitry Ivanov
Reviewers: Alexander Korotkov, Artur Zakirov

1 files changed, 9 insertions, 2 deletions

diff --git a/src/backend/utils/adt/tsquery_util.c b/src/backend/utils/adt/tsquery_util.c
index fe26ad52dd2..0f338aa653d 100644
--- a/src/backend/utils/adt/tsquery_util.c
+++ b/src/backend/utils/adt/tsquery_util.c
@@ -110,6 +110,10 @@ QTNodeCompare(QTNode *an, QTNode *bn)
 				if ((res = QTNodeCompare(an->child[i], bn->child[i])) != 0)
 					return res;
 		}
+
+		if (ao->oper == OP_PHRASE && ao->distance != bo->distance)
+			return (ao->distance > bo->distance) ? -1 : 1;
+
 		return 0;
 	}
 	else if (an->valnode->type == QI_VAL)
@@ -150,7 +154,7 @@ QTNSort(QTNode *in)
 
 	for (i = 0; i < in->nchild; i++)
 		QTNSort(in->child[i]);
-	if (in->nchild > 1)
+	if (in->nchild > 1 && in->valnode->qoperator.oper != OP_PHRASE)
 		qsort((void *) in->child, in->nchild, sizeof(QTNode *), cmpQTN);
 }
 
@@ -190,7 +194,10 @@ QTNTernary(QTNode *in)
 	{
 		QTNode	   *cc = in->child[i];
 
-		if (cc->valnode->type == QI_OPR && in->valnode->qoperator.oper == cc->valnode->qoperator.oper)
+		/* OP_Phrase isn't associative */
+		if (cc->valnode->type == QI_OPR &&
+			in->valnode->qoperator.oper == cc->valnode->qoperator.oper &&
+			in->valnode->qoperator.oper != OP_PHRASE)
 		{
 			int			oldnchild = in->nchild;