From dc31b932d0c017afff2d791c0d42f816fdc4f583 Mon Sep 17 00:00:00 2001 From: Kenan Yao Date: Tue, 7 Apr 2020 14:13:00 +0800 Subject: [PATCH] reference/performance: specify index name of primary key for USE_INDEX_MERGE (#2350) Co-authored-by: Keke Yi <40977455+yikeke@users.noreply.github.com> --- reference/performance/optimizer-hints.md | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/reference/performance/optimizer-hints.md b/reference/performance/optimizer-hints.md index 934ff5ea6d69..e2c5ec9b991e 100644 --- a/reference/performance/optimizer-hints.md +++ b/reference/performance/optimizer-hints.md @@ -191,6 +191,10 @@ select /*+ READ_FROM_STORAGE(TIFLASH[t1], TIKV[t2]) */ t1.a from t t1, t t2 wher select /*+ USE_INDEX_MERGE(t1, idx_a, idx_b, idx_c) */ * from t t1 where t1.a > 10 or t1.b > 10; ``` +> **注意：** +> +> `USE_INDEX_MERGE` 的参数是索引名，而不是列名。对于主键索引，索引名为 `primary`。 + ### NO_INDEX_MERGE() `NO_INDEX_MERGE()` 会关闭优化器的 index merge 功能。