Information Schema not updated after MyISAM packing on v8
Posted by: Frank Peacock
Date: September 02, 2020 11:12PM

Hello,

I have previously used MYISAM tables on v5.6 and v5.7 on Linux Ubuntu without problems. In particular, information correctly appears in the Information Schema after packing indicating the data file size correctly.

I have started using Server version: 8.0.21 - MySQL Community Server - GPL with cPanel on Linux Centos 7. Packing the MYISAM tables produces identical compression ratios as v5.7 so the final file sizes are identical. What is not working is that the information schema on v8 still shows the original average record size and original table size.

I have performed further tests below but the INFORMATION_SCHEMA information about the packed MYISAM table has not updated the lengths of the average_row and data on MySQL v8.

I have tried:
Stopping the mysqld server and then performing mysqlpack and myisamchk.
With external_locking both on and off.
Flushing tables both using mysqladmin and within mysql_client at different stages of the packing and index updating.
Finally I also had to do a 'check table' on the packed table to finally get the row format to update from "Fixed" to "Compressed".

All the above was unnecessary in v5.6 and v5.7. So I presume v8 has changed a great deal or perhaps cPanel is having an impact.

I have also checked the packed table's sdi file. The following options seem incorrect:
The option "stats_auto_recalc=0" may be of significance. I thought that this was only for innodb files.
The option "avg_row_length=0" also be of significance.
The option "pack_record=0" seems incorrect.

The only option which I set and which is correct is "max_rows=11959552".

I would be extremely grateful for any assistance,

Thanks,

Frank

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Information Schema not updated after MyISAM packing on v8
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September 02, 2020 11:12PM


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