From 50e7d02355ee4857247754cccf756e277e6a0d71 Mon Sep 17 00:00:00 2001
From: asahi <mikiyashiki@outlook.com>
Date: Mon, 17 Feb 2025 20:41:03 +0800
Subject: [PATCH] =?UTF-8?q?=E9=98=85=E8=AF=BBinnodb=20icp=E4=BC=98?=
 =?UTF-8?q?=E5=8C=96=E6=96=87=E6=A1=A3?=
MIME-Version: 1.0
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---
 mysql/mysql文档/mysql_索引.md | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/mysql/mysql文档/mysql_索引.md b/mysql/mysql文档/mysql_索引.md
index 04a90ce..9c685b3 100644
--- a/mysql/mysql文档/mysql_索引.md
+++ b/mysql/mysql文档/mysql_索引.md
@@ -31,6 +31,9 @@
       - [开启MRR优化](#开启mrr优化)
       - [mrr控制](#mrr控制)
       - [read\_rnd\_buffer\_size](#read_rnd_buffer_size)
+  - [Index Condition Pushdown(ICP)](#index-condition-pushdownicp)
+    - [关闭ICP](#关闭icp)
+    - [开启ICP](#开启icp)
 
 
 # innodb索引与算法
@@ -360,5 +363,17 @@ select * from t where key_part1 >= 1000 and key_part1 < 2000 and key_part2 = 100
 #### read_rnd_buffer_size
 `read_rnd_buffer_size`用来控制键值的缓冲区大小，当大于该值时，则执行器则对已经缓存的数据根据rowId来进行排序，并通过rowId来获取数据。该值默认为`256K`.
 
+## Index Condition Pushdown(ICP)
+可以通过`optimizer_switch`中的flag来控制`ICP`是否开启，如`index_condition_pushdown`为`on`，代表icp开启。
 
+例如，表`people`包含`（zip_code, last_name, first_name)`索引，执行如下语句
+```sql
+select * from people where zipcode = '95054' and last_name like '%asahi%' and address like '%street%';
+```
+
+### 关闭ICP
+如果ICP优化没有开启，那么数据库首先会根据索引查询`zipcode`为95054的记录，然后查询出后再根据查询出的结果过滤where的后两个条件`last_name like '%asahi%' and address like '%street%'`。
+
+### 开启ICP
+当开启ICP后，数据库会将where的部分过滤条件放在存储引擎层，在索引获取数据同时就会进行where条件的过滤。