Changing a column from uncompressed to compressed for JSON crashes the server

[Alexander Rubin]

Percona server 5.7 includes the compression option https://www.percona.com/doc/percona-server/LATEST/flexibility/compressed_columns.html

When trying to change the field from uncompressed to compressed for JSON, and then select from the table, MySQL crashes.

mysql> alter table tb_name modify json_variables JSON COLUMN_FORMAT compressed;
Query OK, 0 rows affected (0.01 sec)
Records: 0 Duplicates: 0 Warnings: 0

select json_variables from tb_name limit 1\G
...
server crashes.

Error log shows:
2017-07-13T15:21:22.114757Z 3 [ERROR] [FATAL] InnoDB: unsupported compressed BLOB header format

[Alexander Rubin (alikrubin75)]

Please note: this only happens on alter table, not on initial table creation and insertion

[Roel Van de Paar (roel11)]

Alexander, could you please provide full testcase?

[Sveta Smirnova (svetasmirnova)]

Thank you for the report.

I cannot repeat crash, but SELECT fails with error "3142: The JSON binary value contains invalid data." which is not correct behavior too. Set to "Confirmed"

[Sveta Smirnova (svetasmirnova)]

Tested with 5.7.18-16

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-1108