| Bug #101714 | Critical performance issue | ||
|---|---|---|---|
| Submitted: | 23 Nov 2020 6:59 | Modified: | 26 Jan 2021 16:23 |
| Reporter: | Sergey Volkov | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | Connector / NET | Severity: | S5 (Performance) |
| Version: | 8.0.22, 8.0.23 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
[23 Nov 2020 7:02]
Sergey Volkov
Profiler
Attachment: 2020_11_20_13_21_30_forecast_calls.dtp_C_WINDOWS_SysWOW64_inetsrv_w3wp.exe_19.11.2020_12_20_28.png (image/png, text), 234.63 KiB.
[23 Nov 2020 14:37]
Bradley Grainger
MySqlConnector (https://www.nuget.org/packages/MySqlConnector/) doesn't have this bug, and is optimised for performance (https://github.com/mysql-net/MySqlConnector/#performance); you may want to try it out as a workaround until this is fixed.
[30 Nov 2020 23:48]
Matt Stubblefield
Another Profiler screenshot.
Attachment: 8.0.22-profiled.png (image/png, text), 191.85 KiB.
[30 Nov 2020 23:49]
Matt Stubblefield
I profiled 8.0.22 vs 8.0.21 and can verify that it definitely appears to be the Regex constructor right around "ReadColumnValue".
[9 Dec 2020 16:16]
MySQL Verification Team
https://bugs.mysql.com/bug.php?id=101739 marked as duplicate of this one.
[26 Jan 2021 16:23]
Christine Cole
Posted by developer: Fixed as of the upcoming MySQL Connector/NET 8.0.24 release, and here's the proposed changelog entry from the documentation team: Constructing a regular expression for each read diminished the performance of Connector/NET. This fix limits the construction to one instance, which now is reused. Thank you for the bug report.
[15 Mar 2021 5:14]
MySQL Verification Team
Bug #102963 marked as duplicate of this one
[19 Apr 2021 11:10]
MySQL Verification Team
Bug #103305 marked as duplicate of this one.
Description: Reading database is very slow. After profiling it I found that 90% of all time is lost on regex ctor. Class: MySql.Data.MySqlCLient.NativeDriver Method: public IMySqlValue ReadColumnValue(int index, MySqlField field, IMySqlValue valObject) Line: Regex regex = new Regex("(?i)^[0-9A-F]{8}[-](?:[0-9A-F]{4}[-]){3}[0-9A-F]{12}$"); It is huge time loss on each value read. How to repeat: Any read with reader class. Suggested fix: This regex instance should be static, i.e. it will be constructed once.