Releasing LOB space in MySQL or Maria databases
You can release the large object (LOB) storage in the MySQL or Maria databases.
Pre-requisite:
Consider the following points when you plan an upgrade:- You might be able to avoid the downtime by running the alter table
statement before you
upgrade:
If this command fails, an online change of the table before upgrade isn't possible with your version of MySQL. Downtime is required during the upgrade.alter table vc_persistent_record modify persistent_data longtext null, add compessed_data longblob null, lock=none
- Based on the MySQL version you are using, the upgrade or pre-upgrade table change temporarily uses additional space to rebuild the table.
- For bext results, run the statement on a table clone to estimate the upgrade time.
- Use the alter table command only if the table does not include a compressed_data column.
Procedure:
Release LOB storage for MySQL and Maria databases using the following steps:
Post-requisite:
- Verify that the space is
reduced:
select table_schema, sum((data_length+index_length)/1024/1024) AS MB from information_schema.tables group by 1
- Set the versioned_config.upgrade.enabled parameter back to false in the conf/server/installed.properties file.