Cheers
Dave
On Thu, Oct 7, 2010 at 3:40 PM, Robert Haas <robertmhaas@xxxxxxxxx> wrote:
On Mon, Sep 27, 2010 at 3:27 PM, Gurjeet Singh <singh.gurjeet@xxxxxxxxx> wrote:CREATE INDEX (without CONCURRENTLY) tries to acquire a share-lock on
> On Mon, Sep 27, 2010 at 8:50 PM, Dave Crooke <dcrooke@xxxxxxxxx> wrote:
>>
>> Our Java application manages its own schema. Some of this is from
>> Hibernate, but some is hand-crafted JDBC.
>>
>> By way of an upgrade path, we have a few places where we have added
>> additional indexes to optimize performance, and so at startup time the
>> application issues "CREATE INDEX ..." statements for these, expecting to
>> catch the harmless exception "ERROR:Â relation "date_index" already exists",
>> as a simpler alternative to using the meta-data to check for it first.
>>
>> In general, this seems to work fine, but we have one installation where we
>> observed one of these CREATE statements hanging up in the database, as if
>> waiting for a lock, thus stalling the app startup
>
> You can tell if it is really waiting by looking at 'select * from pg_locks',
> and check the 'granted' column.
the table, which will conflict with any concurrent INSERT, UPDATE,
DELETE, or VACUUM. ÂIt probably tries to acquire the lock before
noticing that the index is a duplicate. ÂCREATE INDEX CONCURRENTLY
might be an option, or you could write and call a PL/pgsql function
(or, in 9.0, use a DO block) to test for the existence of the index
before trying create it.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company
