[HACKERS] Equivalence Rules

2014-03-02 Thread Ali Piroozi
Hi My question is: Does PostgreSQL implements equivalence rules(from those are listed in email's attachment)? Which function or which part of source code(in PostgreSQL ) implements the equivalence rules? I think, this should be implemented in query optimization part of PostgreSQL, but which rule

Re: [HACKERS] Equivalence Rules

2014-03-02 Thread Antonin Houska
There are 2 kinds of rules in this document: for joins and for set operations. As for joins, I think they are all about *inner* joins. Postgres (IMO) implements them by not doing anything special if query only contains inner joins. On the other hand, attention has to be paid if there's at least

[HACKERS] Equivalence Rules

2014-02-28 Thread Ali Piroozi
Hi Which equivalence rule from those are listed in email's attachment are implemented in postgresql? where are them? Thanks equivalenceRules.pdf Description: Adobe PDF document -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription:

Re: [HACKERS] Equivalence Rules

2014-02-28 Thread David Johnston
Ali Piroozi wrote Hi Which equivalence rule from those are listed in email's attachment are implemented in postgresql? where are them? What do you mean by where? The various JOINS and UNION/INTERSECT/DIFFERENCE are all defined capabilities. SQL is not purely relational in nature so some of

Re: [HACKERS] Equivalence Rules

2014-02-28 Thread Ali Piroozi
where means, which function or which part of source code. I want to use that(function or part of source code), to produce the equivalence (based on equivalence rules in attachment) Relational Algebra for a given SQL query(Relational Algebra).