Skip to content

[pull] master from Snailclimb:master #102

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
pull merged 2 commits into from
Mar 18, 2021
+1 −1
Merged

[pull] master from Snailclimb:master #102

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
eb6e9ac
fix: 修正单词的错误
taoes Mar 17, 2021
0f8129d
Merge pull request #1131 from taoes/master
Snailclimb Mar 18, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion docs/database/MySQL Index.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -34,7 +34,7 @@

《高性能MySQL》第四章如是说：And, in case you’re wondering, allowing NULL values in the index really doesn’t impact performance 。NULL 值的索引查找流程参考：https://juejin.im/post/5d5defc2518825591523a1db ,相关阅读：[MySQL中IS NULL、IS NOT NULL、!=不能用索引？胡扯！](https://juejin.im/post/5d5defc2518825591523a1db) 。

9. 删除长期未使用的索引，不用的索引的存在会造成不必要的性能损耗 MySQL 5.7 可以通过查询 sys 库的 chema_unused_indexes 视图来查询哪些索引从未被使用
9. 删除长期未使用的索引，不用的索引的存在会造成不必要的性能损耗 MySQL 5.7 可以通过查询 sys 库的 schema_unused_indexes 视图来查询哪些索引从未被使用

10. 在使用 limit offset 查询缓慢时，可以借助索引来提高性能

Expand Down