Forwarded to devs Occasional "ODBC error #HY000: [ma-3.0.8][10.1.48-MariaDB]Prepared statement needs to be re-prepared" during backups

[Bitpalast]

Username: Peter Debik

TITLE

Occasional "ODBC error #HY000: [ma-3.0.8][10.1.48-MariaDB]Prepared statement needs to be re-prepared" during backups

PRODUCT, VERSION, OPERATING SYSTEM, ARCHITECTURE

CentOS 7.9 with latest OS updates
Obsidian, latest MU

PROBLEM DESCRIPTION

Across all of our dedicated servers we occasionally see one or more of these messages in the nightly backup log of full server backups (admin level):

Warning: Domain "domain.tld"
Unable to back up applications. Error: ODBC error #HY000: [ma-3.0.8][10.1.48-MariaDB]Prepared statement needs to be re-prepared

Most often the message only appears exactly once in a backup, sometimes it appears twice or up to five times relating to different domains per message.

STEPS TO REPRODUCE

Cannot be reproduced manually. It appears occasionally, approximately once every 18 full server backups on different machines, e.g. once every 18 weeks on one machine on average. Typical server backup sizes here are 450 GB per machine, approx. 350 subscriptions and 900 domains per machine.

ACTUAL RESULT

Warning: Domain "domain.tld"
Unable to back up applications. Error: ODBC error #HY000: [ma-3.0.8][10.1.48-MariaDB]Prepared statement needs to be re-prepared

EXPECTED RESULT

Backup without SQL error

ANY ADDITIONAL INFORMATION

We'd like to know what the consequence of the behavior is and ideally, how this can be avoided.

YOUR EXPECTATIONS FROM PLESK SERVICE TEAM

Help with sorting out

 

[Aytalina]

Hello Peter,

Thank you for the report.

According to the error message, domain APS applications were not included in a domain backup.

The possible workaround for the issue is to increase 'table_open_cache' and 'table_open_cache', reference:

[MDEV-17124] mariadb 10.1.34, views and prepared statements: ERROR 1615 (HY000): Prepared statement needs to be re-prepared - Jira

jira.mariadb.org

 

[Bitpalast]

Increasing table_definition_cache and table_open_cache a great deal has solved the issue.