From ab639a76240b8b954b75479aa817094c12a96641 Mon Sep 17 00:00:00 2001
From: Frank945946 <108602632+Frank945946@users.noreply.github.com>
Date: Tue, 12 Nov 2024 17:44:49 +0800
Subject: [PATCH] Updated the Schema Cache limitations (#19374)

---
 schema-cache.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/schema-cache.md b/schema-cache.md
index b6b332f348868..6bfd650362bed 100644
--- a/schema-cache.md
+++ b/schema-cache.md
@@ -36,3 +36,8 @@ In scenarios with a large number of databases and tables, the following known is
     - `SHOW FULL TABLES`
     - `FLASHBACK`
     - `ALTER TABLE ... SET TIFLASH MODE ...`
+- When you use tables with the [`AUTO_INCREMENT`](/auto-increment.md) or [`AUTO_RANDOM`](/auto-random.md) attribute, a small schema cache size might cause these tables to frequently enter and leave the cache. You can monitor it through the schema cache hit rate and size on the monitoring panel. This can result in the allocated ID range becoming invalid before being fully used, leading to ID jumps. In write-intensive scenarios, this might even exhaust the ID range. To minimize abnormal ID allocation behavior and improve system stability, it is recommended to take the following measures:
+
+    - Increase the schema cache size to reduce frequent evictions.
+    - Set [`AUTO_ID_CACHE`](/auto-increment.md#auto_id_cache) to `1` to prevent ID jumps.
+    - Properly configure the shard bits and reserved bits of `AUTO_RANDOM` to avoid a too small ID range.
\ No newline at end of file