Re: List of table names of a DB

Sorry, it's not about querying. I am implementing an invalidation mechanism for Postgres Query Cache as part of my masters project. In order to this, I need to store details(like name) of each table the query uses. In essence, I need to store the table names of the cached queries.
Initially, I thought of writing a code that could extract the table names but later discovered that it is a gargantuan task as I shall have to include around 600 production rules as was hinted in a Stackoverflow Exchange post. Hence, I thought of getting hold of the data structure used for storing table names of a DB but I couldn't get it.
Sorry for the long post but do you know where these tables information of a DB gets stored? Or can you suggest me a mechanism(needn't be fully perfect) to extract the table names? I went through the parser of postgres but it was confusing.
Thanks

Date: Fri, 9 Jan 2015 00:46:30 +1300
Subject: Re: [HACKERS] List of table names of a DB
From: dgrowleyml(at)gmail(dot)com
To: in(dot)live(dot)in(at)live(dot)in
CC: pgsql-hackers(at)postgresql(dot)org

On 8 January 2015 at 22:41, Deepak S <in(dot)live(dot)in(at)live(dot)in> wrote:

Hello, I am unable to find the function which retrieves the 'list of names of the tables' used in a DB.

You may find what you want in: select table_name from information_schema.tables;
http://www.postgresql.org/docs/9.4/static/infoschema-tables.html

Reason: I need a mechanism by which I can extract the names of the tables used in a query which has been parsed. My plan is to check for a match of each word in the query with a list of names of the tables used in the current DB so that each hit confirms a 'table name' in the query in most cases.

This sounds rather flaky.
Maybe it would be better to just EXPLAIN the query and see if you get error code 42P01postgres=# \set VERBOSITY verbosepostgres=# explain select * from doesnotexist;ERROR: 42P01: relation "doesnotexist" does not existLINE 1: explain select * from doesnotexist;
Unfortunately this won't help you much if you want to know all of the tables that don't exist.
Also, just for the future, a question like this might be more suited for the pgsql-general(at)postgresql(dot)org list.
Regards
David Rowley