Add support for PREPARE and EXECUTE statement for simple query

[sunng87]

Postgres has a text form of parse-bind-execute query like:

-- parse the statement
PREPARE myplan(type) AS SELECT $1;

-- create portal and execute the statement
EXECUTE myplan(1);

-- remove the statement
DEALLOCATE myplan;

This will allow us to debug extended query, statement binding easier with psql client.

[TwistingTwists]

I am willing to take this up. Can you help me understand how to debug this so that i know what the output looks like?

[sunng87]

Thank you @TwistingTwists !

The idea of this feature is to run extended query (parse-bind-execute) process in simple query protocol.

My idea is to implement it as a hook in our architecture. We will process these PREPARE/EXECUTE/DEALLOCATE statements with the hook.

• PREPARE: just follow how we did with PARSE in extended query. We will use portal store to store it.
• EXECUTE: it's the combination of BIND and EXECUTE
• DEALLOCATE: just like CLOSE in extended query, remove the statement from store.

To see output of this, just run them on a real postgres server.

This features might require changes in pgwire, to enhance the SimpleQueryHandler definition.