Problem compiling function with BEGIN WORK; COMMIT WORK;
Hi,
I need to use the BEGIN WORK; and COMMIT WORK; to lock a table when I'am
doing a SELECT and UPDATE operation.
The code is not compiling, the error is:
[error]ERROR: syntax error at or near "work" at character 1
QUERY: work
CONTEXT: SQL statement in PL/PgSQL function "apr_apanhar_ownership_email"
near line 7
[/error]
And the code is:
[code]
CREATE OR REPLACE FUNCTION "public"."apr_apanhar_ownership_email" (ppid
int4, out ppid_email_envio int4) RETURNS integer AS
$body$
DECLARE
pPID alias for $1;
vID_EMAIL_ENVIO int4;
BEGIN
begin work;
lock table atem_emails_envios in access exclusive mode;
select id_email_envio from atem_emails_envios
where dat_sended is null
and (i_started is null or i_started < (current_timestamp - '2
hours'::interval))
and (pid is null or pid = pPID)
order by dat_inserted asc
limit 1
into vID_EMAIL_ENVIO;
update atem_emails_envios
set
i_started = current_timestamp,
pid = pPID
where id_email_envio = vID_EMAIL_ENVIO;
commit work;
ppid_email_envio := vID_EMAIL_ENVIO;
END;
$body$
LANGUAGE 'plpgsql' VOLATILE RETURNS NULL ON NULL INPUT SECURITY INVOKER;
[/code]
What is wrong here? Can someone give me a clue.
Best Regards,
On 25/04/2010 9:07 AM, Andre Lopes wrote:
Hi,
I need to use the BEGIN WORK; and COMMIT WORK; to lock a table when I'am
doing a SELECT and UPDATE operation.
PostgreSQL's server-side functions do *not* support transaction
management. They're functions that're used inside an existing transaction.
However, if you do not explcitly BEGIN a transaction before calling your
function, the statement your function runs in will start and stop its
own transaction. In other words, these two things are equivalent:
BEGIN;
SELECT my_function();
COMMIT;
and
SELECT my_function();
(outside an existing transaction)
Because your function is *always* inside a transaction, it can always
acquire locks and the like. It doesn't need to explicitly start a
transaction first.
--
Craig Ringer