Bug #94330 Test for possible compressed failures before upgrade?
Submitted: 14 Feb 20:19 Modified: 27 Feb 15:51
Reporter: monty solomon Email Updates:
Status: Verified Impact on me:
Category:MySQL Server: Documentation Severity:S3 (Non-critical)
Version:5.7.24 OS:Any
Assigned to: CPU Architecture:Any

[14 Feb 20:19] monty solomon
In the 5.7.24 release notes there is a warning about the possible failure of some operations on row sizes in compressed tables that are close to the maximum row size.

The warning mentions INSERT operations. Are there any concerns about UPDATE operations?

Is it possible to determine if there will be a problem with existing compressed tables before upgrading to 5.7.24?

How to repeat:
The zlib library version bundled with MySQL was raised from version 1.2.3 to version 1.2.11. MySQL implements compression with the help of the zlib library.

The zlib compressBound() function in zlib 1.2.11 returns a slightly higher estimate of the buffer size required to compress a given length of bytes than it did in zlib version 1.2.3. The compressBound() function is called by InnoDB functions that determine the maximum row size permitted when creating compressed InnoDB tables or inserting rows into compressed InnoDB tables. As a result, CREATE TABLE ... ROW_FORMAT=COMPRESSED or INSERT operations with row sizes very close to the maximum row size that were successful in earlier releases could now fail.
[27 Feb 15:51] Sinisa Milivojevic

Thank you for your bug report.

As it happens, I know a lot about problems with new zlib version used.

Verified as reported.
[27 Feb 15:53] Sinisa Milivojevic
Only to add that both UPDATE and REPLACE  are affected.

This is a documentation-only bug, since we do not maintain zlib library.