Category: Uncategorized

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

CitiBank – frontem do klienta (polish only)

Tak się złożyło, że jestem klientem CitiBanku.

Mam u nich konto biznesowe, i z tej okazji muszę co jakiś czas korzystać z ich systemu webowego.

Już parę razy do nich pisałem, że system jest wolny, nie zawsze wyświetla wszystkie informacje, ma problemy z transakcjami w niestandardowych walutach, ale to co zobaczyłem dziś mnie po prostu powaliło.

Continue reading CitiBank – frontem do klienta (polish only)

Getting record by 2 criteria, ordered by third – how to do it quickly?

Let's assume we have a simple table:

CREATE TABLE objects (
    id          serial primary key,
    category    INT4        NOT NULL DEFAULT 0,
    object_type INT4        NOT NULL DEFAULT 0,
    entered_on  TIMESTAMPTZ NOT NULL DEFAULT now()
);

(This is simplification, but it contains all necessary columns).

What should I do to be able to quickly get 50 newest objects in given category/object_type (or in many categories/many object_types, or in all categories/object_types), optionally with limiting entered_on “older than …".

Continue reading Getting record by 2 criteria, ordered by third – how to do it quickly?

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