On 25.11.2010 12:51, MIkhail Puzanov wrote: > > > 2010/11/25 Tom Lane <[email protected] <mailto:[email protected]>> > > "Mikhail V. Puzanov" <[email protected] > <mailto:[email protected]>> writes: > > -- increment and get the counter if exists > > UPDATE sequences SET counter = counter + 1 > > WHERE section = 'testSection' AND name = 'testKey' > > RETURNING counter; > > Seems that what you have here is a bad manual implementation of a > sequence. Why don't you use a real sequence object and nextval()? > > > > Well, if I use the real sequence, I'll need unpredictable number of them > and will have to store mapping (section, name)->sequenceName, and > also will have to create those sequences dynamically the similar way. >
Finally the problem solved with application level locks (that works for only one application server, but suits our needs for now). This also works http://www.postgresql.org/docs/current/static/plpgsql-control-structures.html#PLPGSQL-UPSERT-EXAMPLE but we need some more or less cross-DBMS approach.
