fix index degeneration

src/graph/optimizer/rule/IndexScanRule.cpp

@@ -66,7 +66,10 @@ StatusOr<OptRule::TransformResult> IndexScanRule::transform(OptContext* ctx,
     FilterItems items;
     ScanKind kind;
     NG_RETURN_IF_ERROR(analyzeExpression(filter, &items, &kind, isEdge(groupNode)));
-    NG_RETURN_IF_ERROR(createIndexQueryCtx(iqctx, kind, items, qctx, groupNode));
+    auto status = createIndexQueryCtx(iqctx, kind, items, qctx, groupNode);
+    if (!status.ok()) {
+      NG_RETURN_IF_ERROR(createIndexQueryCtx(iqctx, qctx, groupNode));
+    }
   }
 
   const auto* oldIN = groupNode->node();
@@ -481,20 +484,15 @@ std::vector<IndexItem> IndexScanRule::findValidIndex(graph::QueryContext* qctx,
   std::vector<IndexItem> validIndexes;
   // Find indexes for match all fields by where condition.
   for (const auto& index : indexes) {
-    bool allColsHint = true;
     const auto& fields = index->get_fields();
     for (const auto& item : items.items) {
       auto it = std::find_if(fields.begin(), fields.end(), [item](const auto& field) {
         return field.get_name() == item.col_;
       });
-      if (it == fields.end()) {
-        allColsHint = false;
-        break;
+      if (it != fields.end()) {
+        validIndexes.emplace_back(index);
       }
     }
-    if (allColsHint) {
-      validIndexes.emplace_back(index);
-    }
   }
   // If the first field of the index does not match any condition, the index is
   // invalid. remove it from validIndexes.

tests/tck/features/match/IndexSelecting.feature

@@ -0,0 +1,99 @@
+# Copyright (c) 2021 vesoft inc. All rights reserved.
+#
+# This source code is licensed under Apache 2.0 License.
+Feature: Index selecting for match statement
+
+  Background: Prepare a new space
+    Given an empty graph
+    And create a space with following options:
+      | partition_num  | 9                |
+      | replica_factor | 1                |
+      | vid_type       | FIXED_STRING(30) |
+      | charset        | utf8             |
+      | collate        | utf8_bin         |
+    And having executed:
+      """
+      CREATE tag player(name string, age int, score int, gender bool);
+      """
+    And having executed:
+      """
+      INSERT VERTEX player(name, age, score, gender) VALUES "Tim Duncan":("Tim Duncan", 42, 28, true),"Yao Ming":("Yao Ming", 38, 23, true),"Nneka Ogwumike":("Nneka Ogwumike", 35, 13, false);
+      """
+    And having executed:
+      """
+      create tag index player_index on player();
+      create tag index player_name_index on player(name(8));
+      create tag index player_age_name_index on player(age,name(8));
+      """
+    And wait 3 seconds
+
+  Scenario: Test Index selecting
+    When submit a job:
+      """
+      rebuild tag index player_index;
+      """
+    Then wait the job to finish
+    When submit a job:
+      """
+      rebuild tag index player_name_index;
+      """
+    Then wait the job to finish
+    When submit a job:
+      """
+      rebuild tag index player_age_name_index;
+      """
+    Then wait the job to finish
+    # Prefix Index
+    When profiling query:
+      """
+      MATCH (v:player {name: "Yao Ming"}) RETURN v.name AS name
+      """
+    Then the result should be, in any order, with relax comparison:
+      | name       |
+      | "Yao Ming" |
+    And the execution plan should be:
+      | id | name           | dependencies | operator info                                       |
+      | 6  | Project        | 2            |                                                     |
+      | 2  | AppendVertices | 5            |                                                     |
+      | 5  | IndexScan      | 0            | {"indexCtx": {"columnHints":{"scanType":"PREFIX"}}} |
+      | 0  | Start          |              |                                                     |
+    # Range Index
+    When profiling query:
+      """
+      MATCH (v:player) WHERE v.name > "Tim" and v.name < "Zom" RETURN v.name AS name
+      """
+    Then the result should be, in any order, with relax comparison:
+      | name         |
+      | "Yao Ming"   |
+      | "Tim Duncan" |
+    And the execution plan should be:
+      | id | name           | dependencies | operator info                                      |
+      | 9  | Project        | 7            |                                                    |
+      | 7  | Filter         | 2            |                                                    |
+      | 2  | AppendVertices | 6            |                                                    |
+      | 6  | IndexScan      | 0            | {"indexCtx": {"columnHints":{"scanType":"RANGE"}}} |
+      | 0  | Start          |              |                                                    |
+    # Degeneration to FullScan Index
+    When executing query:
+      """
+      MATCH (v:player) WHERE v.score < 20 RETURN v.name AS name
+      """
+    Then the result should be, in any order, with relax comparison:
+      | name             |
+      | "Nneka Ogwumike" |
+    # Degeneration to Prefix Index
+    When profiling query:
+      """
+      MATCH (v:player) WHERE v.name == "Tim Duncan" and v.score == 28 RETURN v.name AS name
+      """
+    Then the result should be, in any order, with relax comparison:
+      | name         |
+      | "Tim Duncan" |
+    And the execution plan should be:
+      | id | name           | dependencies | operator info                                       |
+      | 9  | Project        | 7            |                                                     |
+      | 7  | Filter         | 2            |                                                     |
+      | 2  | AppendVertices | 6            |                                                     |
+      | 6  | IndexScan      | 0            | {"indexCtx": {"columnHints":{"scanType":"PREFIX"}}} |
+      | 0  | Start          |              |                                                     |
+    Then drop the used space