PostgreSQL make CPU Usage 100%?

Question

I'm using PostgreSQL in my WPF Application .

Sometime the PostgreSQL makes CPU Usage up-to 100%.

I have encountered this issue many time, but I don't know the reason.

The snapshot image in Task Manager is below

Note that, When this bug occurs, I kill my application exe, and wait for during 5 minutes after that, but the status in task manager still not change. CPU still 100%

I see that, it usually happens after Window Update. And I must restart the computer to by pass this.

I'm using PostgreSQL 9.3 .

Anyone can show me the way to fix this.

Thank you :)

Answer 1

If you are able to still access postgres, one thing I'd look at is do you have any queries that might be hung up

SELECT
  pid,
  now() - pg_stat_activity.xact_start AS duration,
  query,
  state
FROM pg_stat_activity
WHERE (now() - pg_stat_activity.query_start) > interval '4 minutes';

if there is indeed a query that has been alive longer than it should be, you can delete like so:

SELECT pg_cancel_backend(<pid>);

This might not be the problem, but it will at least reduce the number of possibilities.

Answer 2

如果您不在数据库中使用索引，那么大多数情况下会出现问题，请对经常使用的字段使用索引，特别是如果您使用“order by”或聚合（例如 sum 和 count）