2012/1/8 Thomas Kellerer <spam_eater@xxxxxxx> wrote: > I think you are better off using bytea unless you need to access only parts > of the blob regularly. That's a valid tip. But it's to the current JDBC implementation to take action because it currently leads to disk space leakage when using JDBC and JPA/Hibernate. After a tedious time of bug searching I found a possible solution and a testimonial here: "One of the problems with the JDBC driver (and this affects the ODBC driver also), is that the specification assumes that references to BLOBs (Binary Large OBjects) are stored within a table, and if that entry is changed, the associated BLOB is deleted from the database. As PostgreSQL stands, this doesn't occur." (taken from the docs http://www.postgresql.org/docs/9.1/static/lo.html ) In addition, unfortunately the (lo_unlink) problem of LargeObjects and BLOBs is not mentioned in the JDBC docs: http://jdbc.postgresql.org/documentation/head/binary-data.html Stefan 2012/1/8 Thomas Kellerer <spam_eater@xxxxxxx>: > Stefan Keller wrote on 06.01.2012 19:04: > >> I maintain images (from Webcams). In the Java and Hibernate (JPA) code >> I specified a @Lob annotation on class MyData and a attribte/data type >> "byte[] mydata;". Hibernate then generates two tables in PostgreSQL, >> one called MyData with a column mydata of type oid and an internal one >> called pg_largobjects (which contain foreign keys to the oid). That's >> also explained in the JDBC docs [1], saying "PostgreSQL provides two >> distinct ways to store binary data. Binary data can be stored in a >> table using the data type bytea or by using the Large Object feature >> which stores the binary data in a separate table in a special format >> and refers to that table by storing a value of type oid in your >> table." > > > I think you are better off using bytea unless you need to access only parts > of the blob regularly. > > > -- > Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
