feat: support using custom index with SelectQueryBuilder in MySQL (#7755

) * Support using custom index for MySqlDriver. * Update select-query-builder.md Co-authored-by: Umed Khudoiberdiev <pleerock.me@gmail.com>
typeorm · Nov 9, 2021 · f79ae58 · f79ae58
1 parent 4aaafdf
commit f79ae58
Show file tree

Hide file tree

Showing 4 changed files with 54 additions and 2 deletions.
diff --git a/docs/select-query-builder.md b/docs/select-query-builder.md
@@ -22,6 +22,7 @@
 * [Streaming result data](#streaming-result-data)
 * [Using pagination](#using-pagination)
 * [Set locking](#set-locking)
+* [Use custom index](#use-custom-index)
 * [Max execution time](#max-execution-time)
 * [Partial selection](#partial-selection)
 * [Using subqueries](#using-subqueries)
@@ -916,9 +917,20 @@ const users = await getRepository(User)
 
 Optimistic locking works in conjunction with both `@Version` and `@UpdatedDate` decorators.
 
+## Use custom index
+
+You can provide a certain index for database server to use in some cases. This feature is only supported in MySQL.
+
+```typescript
+const users = await getRepository(User)
+    .createQueryBuilder("user")
+    .useIndex("my_index") // name of index
+    .getMany();
+```
+
 ## Max execution time
 
-We can drop slow query to avoid crashing the server. Only MySQL driver is supported at the moment:
+We can drop slow query to avoid crashing the server.
 
 ```typescript
 const users = await getRepository(User)

diff --git a/src/query-builder/QueryExpressionMap.ts b/src/query-builder/QueryExpressionMap.ts
@@ -157,6 +157,13 @@ export class QueryExpressionMap {
      */
     take?: number;
 
+    /**
+     * Use certain index for the query.
+     *
+     * SELECT * FROM table_name USE INDEX (col1_index, col2_index) WHERE col1=1 AND col2=2 AND col3=3;
+     */
+    useIndex?: string;
+
     /**
      * Locking mode.
      */

diff --git a/src/query-builder/SelectQueryBuilder.ts b/src/query-builder/SelectQueryBuilder.ts
@@ -966,6 +966,17 @@ export class SelectQueryBuilder<Entity> extends QueryBuilder<Entity> implements
         return this;
     }
 
+    /**
+     * Set certain index to be used by the query.
+     *
+     * @param index Name of index to be used.
+     */
+    useIndex(index: string): this {
+        this.expressionMap.useIndex = index;
+
+        return this;
+    }
+
     /**
      * Sets locking mode.
      */
@@ -1441,6 +1452,14 @@ export class SelectQueryBuilder<Entity> extends QueryBuilder<Entity> implements
             }
         }
 
+        // Use certain index
+        let useIndex: string = "";
+        if (this.expressionMap.useIndex) {
+            if (this.connection.driver instanceof MysqlDriver) {
+                useIndex = ` USE INDEX (${this.expressionMap.useIndex})`;
+            }
+        }
+
         // create a selection query
         const froms = this.expressionMap.aliases
             .filter(alias => alias.type === "from" && (alias.tablePath || alias.subQuery))
@@ -1454,7 +1473,7 @@ export class SelectQueryBuilder<Entity> extends QueryBuilder<Entity> implements
         const select = this.createSelectDistinctExpression();
         const selection = allSelects.map(select => select.selection + (select.aliasName ? " AS " + this.escape(select.aliasName) : "")).join(", ");
 
-        return select + selection + " FROM " + froms.join(", ") + lock;
+        return select + selection + " FROM " + froms.join(", ") + lock + useIndex;
     }
 
     /**

diff --git a/test/functional/query-builder/select/query-builder-select.ts b/test/functional/query-builder/select/query-builder-select.ts
@@ -447,4 +447,18 @@ describe("query builder > select", () => {
 
         expect(sql).contains("SELECT /*+ MAX_EXECUTION_TIME(1000) */");
     })));
+
+    it("Support using certain index", () => Promise.all(connections.map(async connection => {
+        // `USE INDEX` is only supported in MySQL
+        if (!(connection.driver instanceof MysqlDriver)) {
+            return;
+        }
+
+        const sql = connection
+            .createQueryBuilder(Post, "post")
+            .useIndex("my_index")
+            .getSql();
+
+        expect(sql).contains("FROM post USE INDEX (my_index)");
+    })));
 });