Tag: waiting

Waiting for 8.4 – sql-wrappable RETURNING

In PostgreSQL 8.2, we got “RETURNING" clause in INSERT/UPDATE/DELETE queries.

Unfortunately it could not be used as source of rows for anything in sql.

insert into table_backup delete from table where ... returning *;

Well, it's still not possible, but it is a one step closer, thanks to patch written and committed by Tom Lane on 31st of October:

Allow SQL-language functions to return the output of an INSERT/UPDATE/DELETE
RETURNING clause, not just a SELECT as formerly.
 
A side effect of this patch is that when a set-returning SQL function is used
in a FROM clause, performance is improved because the output is collected into
a tuplestore within the function, rather than using the less efficient
value-per-call mechanism.

Continue reading Waiting for 8.4 – sql-wrappable RETURNING

Waiting for 8.4 – Common Table Expressions (WITH queries)

On 4th of September Tom Lane committed another great patch. This one is very large, and even after applying – it's has some rough edges. There will be need for additional patches to make the functionality fully robust, but the fact that it got committed means that it will be available in final 8.4.

What does it do?

Continue reading Waiting for 8.4 – Common Table Expressions (WITH queries)

Waiting for 8.4 – new FSM (Free Space Map)

On 30th of September, Heikki Linnakangas committed his patch that changes FSM:

Rewrite the FSM. Instead of relying on a fixed-size shared memory segment, the
free space information is stored in a dedicated FSM relation fork, with each
relation (except for hash indexes; they don't use FSM).
 
This eliminates the max_fsm_relations and max_fsm_pages GUC options; remove any
trace of them from the backend, initdb, and documentation.
 
Rewrite contrib/pg_freespacemap to match the new FSM implementation. Also
introduce a new variant of the get_raw_page(regclass, int4, int4) function in
contrib/pageinspect that let's you to return pages from any relation fork, and
a new fsm_page_contents() function to inspect the new FSM pages.

Continue reading Waiting for 8.4 – new FSM (Free Space Map)

Waiting for 8.4 – database-level lc_collation and lc_ctype

On 23rd of September, Heikki Linnakangas committed patch that was written by Radek Strnad (actually committed patch is a stripped-down version of original).

What it does? It adds ability to have (finally!) different collation order and character categories for different databases.

Continue reading Waiting for 8.4 – database-level lc_collation and lc_ctype

Waiting for 8.4 – ordered data loading in pg_dump

Great (and admittedly long overdue) patch by Tom Lane:

Make pg_dump --data-only try to order the table dumps so that foreign keys'
referenced tables are dumped before the referencing tables.  This avoids
failures when the data is loaded with the FK constraints already active.
If no such ordering is possible because of circular or self-referential
constraints, print a NOTICE to warn the user about it.

What it exactly means?

Continue reading Waiting for 8.4 – ordered data loading in pg_dump

Waiting for 8.4 – UNION / INTERSECT / EXCEPT

During last month or so, Tom Lane commited changes in PostgreSQL, which were foundations for adding hash-based versions of popular features.

I already described first such feature – DISTINCT.

Now, there were 3 more commits which were related to this:

Continue reading Waiting for 8.4 – UNION / INTERSECT / EXCEPT