I run Sql server instance and a dot.net core app on the same server for a while and today is the first time I came across with this issue, my website doesn't get data from the server and it gets this error:
There is insufficient system memory in resource pool 'internal' to run this query. Error: 596, Severity: 21, State: 1. (Params:). The error is printed in terse mode because there was error during formatting. Tracing, ETW, notifications etc are skipped. A severe error occurred on the current command. The results, if any, should be discarded.
and this error as well:
Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
The sql server version:
Microsoft SQL Server 2017 (RTM-CU16) (KB4508218) - 14.0.3223.3 (X64)
Jul 12 2019 17:43:08 Copyright (C) 2017 Microsoft Corporation Express Edition (64-bit) on Linux (Ubuntu 16.04.6 LTS)
It used to work fine for more than 3 months without any error.
How can I find out what is causing Sql server to use all this cpu all of a sudden?