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Re: Large Object to Bytea Conversion

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Hello Dimitri,

Cool, thank you.

Even though.. it looks a little... ehm... well optimized? Or shall I say hard to read? However, it should work for what I want.

Shouldn't such a thing be at least in contrib? How about the reverse, filling a large object with a bytea value? Admittedly, this is less attractive ;-)

Regards

Markus

Dimitri Fontaine wrote:
Hi,

Le mardi 14 novembre 2006 14:36, Markus Schiltknecht a écrit :
I want to convert some large objects to bytea fields on the server.
Searching through the documentation didn't reveal any hints. Am I
missing something or is there really no such thing as a
lo_convert_to_bytea function?

You may want to try this code given on IRC by i-can't-remember-who:

CREATE FUNCTION _phpads_agg_concat (bytea, bytea) RETURNS bytea AS $_$SELECT $1 || $2$_$ LANGUAGE sql IMMUTABLE STRICT; CREATE AGGREGATE phpads_agg_concat (bytea) (SFUNC = _phpads_agg_concat, STYPE = bytea, INITCOND = '');

EXPLAIN ANALYZE SELECT phpads_agg_concat(data) FROM (SELECT data FROM pg_largeobject WHERE loid = 24513361 ORDEY BY pageno) t; QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------
Aggregate (cost=10.62..10.63 rows=1 width=32) (actual time=4.682..4.685 rows=1 loops=1) -> Index Scan using pg_largeobject_loid_pn_index on pg_largeobject (cost=0.00..10.57 rows=4 width=1863) (actual time=0.075..0.162 rows=4 loops=1)
         Index Cond: (loid = 24513361::oid)
 Total runtime: 5.146 ms


CREATE FUNCTION phppgads_lo_readall(oid) RETURNS bytea AS $_$SELECT phpads_agg_concat(data) FROM (SELECT data FROM pg_largeobject WHERE loid = $1 ORDEY BY pageno) t$_$ LANGUAGE sql STRICT;


Hope this will help,



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