Bug #100512 adaptive hash index(AHI) building causing contention on btr_search_latches
Submitted: 13 Aug 2020 9:17 Modified: 25 Aug 2020 6:38
Reporter: Zhou Xinjing (OCA) Email Updates:
Status: Verified Impact on me:
None 
Category:MySQL Server: InnoDB storage engine Severity:S5 (Performance)
Version:5.7.31,8.0.21 OS:Linux (3.10.107)
Assigned to: CPU Architecture:x86 (96 cores)
Tags: performance

File: Maximum allowed size is 3MB.
Description:
Privacy:

If the data you need to attach is more than 3MB, you should create a compressed archive of the data and a README file that describes the data with a filename that includes the bug number (recommended filename: mysql-bug-data-100512.zip) and upload one to sftp.oracle.com. A free Oracle Web (SSO) account (the one you use to login bugs.mysql.com) and a client that supports SFTP are required in order to access the SFTP server.

To upload the file to sftp.oracle.com:

  1. Open an SFTP client and connect to sftp.oracle.com. Specify port 2021 and remote directory /support/incoming/.
  2. Log in with your newly created Oracle Web account (email address) and password.
  3. Upload the archive to /support/incoming.
  4. Once you have uploaded the file, add a comment to this bug to notify us about it.
Example: sftp -oPort=2021 -oUser=email sftp.oracle.com:/support/incoming

Usage Notes: This directory is unlistable, which means that once you have uploaded your file, you will not be able to see it. A file cannot be uploaded more than once with the same filename. The filename must be changed before attempting to upload the file again. The filename should always start with mysql-bug- prefix. Files are retained on the SFTP server for 7 days and then permanently removed.

[13 Aug 2020 9:23] Zhou Xinjing
This patch implements the idea described above

Attachment: ahi_build_contention_avoidance.patch (application/octet-stream, text), 870 bytes.

[14 Aug 2020 8:43] Zhou Xinjing
Visualization of the experiment on 8.0.21

Attachment: 8.0.21, oltp_read_only, 200GB BP, 100GB table, 256 users.pdf (application/pdf, text), 62.49 KiB.

[14 Aug 2020 8:45] Zhou Xinjing
Visualization of the experiment on 8.0.21.

Attachment: vis.pdf (application/pdf, text), 62.49 KiB.