From Complex to Simple: Answering Questions

Consider these two different definitions of the same term: a replication slot in Postgres.

1. It’s a slot in a leader database instance named after a replica, which lets the leader keep track of what data is replicated to the replica and what is not. So if a replica falls behind, the leader sees that in its replication slot and doesn’t remove the replication data until the replica recovers.

2. It’s a slot in a leader database instance which is usually named after a replica, and which keeps track of a LSN position and latest transaction id of a replica. So if at least one replica falls behind, WAL segments following its LSN won’t be removed, even if they don’t fit into the wal_keep_segments setting. This allows to get rid of WAL archiving via archive_command and rely just on the streaming replication.

And now imagine being asked a question: what is a replication slot in Postgres?

Which of the two definitions will you tell?

If you would use the second one to explain the term to an intern, they would probably end up being more confused and frustrated than they were before asking.

If you would use the first one answering to a senior database administrator, they would probably think that you have no idea how replication in Postgres actually works and would go search the Internet themselves.

So, when answering questions, you should consider the background of the person who’s asking to make the response short and helpful.

Keeping it short makes your response look simple (not in a sense that it uses primitive words, but in a sense that it is easy to grasp given the common background).

I like answering questions, because trying to come up with a simple and helpful response for anyone is quite compelling and interesting.

And remember: there’s no such thing as a “stupid question”. Every question deserves to be answered, no matter how simple or complex it is.

Love your questions,
Kostya.