[pgpool-hackers: 4301] Proposal: Add user_redirect_preference_list

[Bo Peng]

I would like to add a new GUC parameter "user_redirect_preference_list" to 4.5
to allow routing queries to a specific backend node for a specific user connection.

Currently, we have database_redirect_preference_list and app_name_redirect_preference_list,
which allow routing queries to a specific backend node for a specific database connection or
a specific client application connection.

I think the use case, which uses a connection user based load balance, is also needed.

For example, an application has GUI management console and server daemon,
which connect to the same database. GUI management console mainly issues SELECT
and server daemon mainly issues INSERT.
In such case, users may want to route all queries issued by GUI management console
to standby servers to reduce the load on primary server.

To handle such case, normally we can use app_name_redirect_preference_list.
However, in some applications the application name may not be configurable.

That is the reason why I want to add this feature.

Any comments?

-- 
Bo Peng <pengbo at sraoss.co.jp>
SRA OSS LLC
https://www.sraoss.co.jp/