PG 7.3: Query Meta Data with the JDBC-driver
От | Henner Zeller |
---|---|
Тема | PG 7.3: Query Meta Data with the JDBC-driver |
Дата | |
Msg-id | Pine.LNX.4.44.0212022025090.6323-100000@kupfersulfat.toxine.lan обсуждение исходный текст |
Ответы |
Re: PG 7.3: Query Meta Data with the JDBC-driver
(Kris Jurka <books@ejurka.com>)
Re: PG 7.3: Query Meta Data with the JDBC-driver (snpe <snpe@snpe.co.yu>) |
Список | pgsql-hackers |
Hi, Just compiled the 7.3 branch from source and made some tests using the JDBC driver coming with it. I did some tests with the henplus JDBC-shell and noticed some problems quering the database meta data: o the foreign key name is 'wierd' --- DatabaseMetaData meta = conn.getMetaData(); ResultSet rset = meta.getImportedKeys(null,null, 'bar'); rset.next(); String foreignKeyName=rset.getString(12); --- resultsin names that seemingly contains the internal representation: fk_foo_id\000bar\000foo\000UNSPECIFIED\000fooref\000id\000 (see below for an example) o It takes _ages_ to retrieve the meta data. While doing a 'describe', the postmaster process runs on 100% CPU. And:it takes extremly different amounts of time. Executing the describe-command below, it took (56.285 sec, 12.799sec, 5 min 13.468, 12.203 sec) to execute the same command. This look very like a missing or random break-conditionsomewhere in a loop ? o this might be a minor point, but annoying as well: the columns are not ordered in the sequence the're created in thetable. If this cannot be reproduced, I'll try to track this down, but probably this seems simple to you (BTW: doing this with the current 7.4development CVS on my machine, this results in a segmentation fault on the postmaster side - this indicates, that there indeed is a problem ..) ===============8<============== pg> create table foo (id int4 constraint pk_foo primary key); pg> create table bar ( id int4 constraint pk_bar primary key, fooref int4 constraint fk_foo_idreferences foo(id) ); pg> describe bar catalog: postgres'->' : referencing --------+---------+------+---------+--------+------------------------------------------------------------+column | type | null | default | pk | fk | --------+---------+------+---------+--------+------------------------------------------------------------+fooref | int4(4)| YES | [NULL] | | fk_foo_id\000bar\000foo\000UNSPECIFIED\000fooref\000id\000 | | | | | | -> foo(id) |id | int4(4) | NO | [NULL] | pk_bar| | --------+---------+------+---------+--------+------------------------------------------------------------+ 56.285 sec =============================== ciao, -hen BTW: henplus JDBC-Shell can be found <http://henplus.sourceforge.net/>
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