Determine whether a disk is full

When the disk space of a compute node or coordinator node reaches its limit, the entire instance is locked.

Check whether an instance is locked

Connect to the instance and run the following command to check whether the instance is locked:

show rds_force_trans_ro_non_sup;

If the value of rds_force_trans_ro_non_sup is on in the response, the instance is locked and in the read-only state.

Clear data

When an instance is locked because the disk is full, TRUNCATE, DROP and GRANT operations are still supported on data tables. You can use these operations to clear data until the disk space falls within the threshold. Then, the instance is automatically unlocked within about five minutes.

Notice When the instance is locked, DELETE operations are not supported. When you execute DELETE statements, data is written to pg_xlog, which consumes disk space.

You can also execute the following statement to query the table size:

select pg_size_pretty(pg_total_relation_size('test'));