Re: File content logging during execution of COPY queries

On 10/20/2016 12:36 PM, Aleksander Alekseev wrote:
>>>> According to my colleagues it would be very nice to have this feature.
>>>> For instance, if you are trying to optimize PostgreSQL for application
>>>> that uses COPY and you don't have access to or something like this.
>>>> It could also be useful in some other cases.
>>> This use-case doesn't really make much sense to me. Can you explain it
>>> in more detail? Is the goal here to replicate all of the statements
>>> that are changing data in the database?
>> The idea is to record application workload in real environment and write
>> a benchmark based on this record. Then using this benchmark we could try
>> different OS/DBMS configuration (or maybe hardware), find an extremum,
>> then change configuration in production environment.
>>
>> It's not always possible to change an application or even database (e.g.
>> to use triggers) for this purpose. For instance, if DBMS is provided as
>> a service.
>>
>> Currently PostgreSQL allows to record all workload _except_ COPY
>> queries. Considering how easily it could be done I think it's wrong.
>> Basically the only real question here is how it should look like in
>> postgresql.conf.
> OK, how about introducing a new boolean parameter named log_copy?
> Corresponding patch is attached.
>
This is a useful feature I was waiting for some time.
If some application which workload you want to collect is using COPY
statement, then recording network traffic was your only option.

--
Grigory Smolkin
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company