MySQL插入/更新/删除/选择有时会变慢

Question

As I am using InnoDB as a database engine, the query goes slower sometimes it takes 20 seconds or more often.

I know the solution it can be done via my.conf to change the value of innodb_flush_log_at_trx_commit to 2 it can solve my problem I also want to do that but as I have shared hosting so they are not allowing me to do that.

MySQL version: 5.6.32-78.1

I also tried with MySQL query

mysql> SHOW VARIABLES LIKE 'innodb_flush_log_at_trx_commit';
+--------------------------------+-------+
| Variable_name                  | Value |
+--------------------------------+-------+
| innodb_flush_log_at_trx_commit | 1     |
+--------------------------------+-------+
1 row in set

And i tried this query

mysql> SET GLOBAL innodb_flush_log_at_trx_commit=2;

but it is also not allowing me too because I don't have super privileges to perform this action.

I have database with 25 tables , and in 4 tables there are 4000+ records and in rest tables, there are below 100 records

So is there any other solution to speed up the query performance.? Any help will be appreciated.

Answer 1

Use profile to check the cost time in each step;

1. set profiling=1;
2. Run you query;
3. Check the query: show profiles;
4. List the time cost: show profile block io,cpu for query N;

Find the step which has the high Duration

It shows like this

Possible problem: Index, Order by, File sort, Use temp table..