Relevant system information:

• OS: Ubuntu 18.04.5
• PostgreSQL PostgreSQL 12.8
• TimescaleDB version 2.5.0
• Installation method: AWS Image

Describe the bug

The show_chunks function's older_than argument needs the data to be the same type as the time column.

However, in the _timescaledb_internal.policy_compression_integer function, it casts values to BIGINT. So if your time column is an INT, the compression policy will fail.

In the below code link, the lag_integer value is a BIGINT.

To Reproduce
Create a table with an INTEGER time column, use set_integer_now_func to set the function type, and then add a compression policy.

You will start seeing errors in the logs:

2021-11-02 11:19:30.087 UTC [12436] ERROR:  invalid time argument type "bigint"
2021-11-02 11:19:30.087 UTC [12436] HINT:  Try casting the argument to "integer".
2021-11-02 11:19:30.087 UTC [12436] CONTEXT:  PL/pgSQL function _timescaledb_internal.policy_compression_integer(integer,integer,bigint,integer,boolean,boolean) line 17 at FOR over SELECT rows
	SQL statement "CALL _timescaledb_internal.policy_compression_integer(
	            job_id, htid, lag_integer,
	            maxchunks, verbose_log, recompress_enabled )"
	PL/pgSQL function _timescaledb_internal.policy_compression(integer,jsonb) line 62 at CALL