Re: timeout on lock feature
| От | Theo Kramer |
|---|---|
| Тема | Re: timeout on lock feature |
| Дата | |
| Msg-id | 200104180434.f3I4Ys322280@flame.co.za обсуждение |
| Ответ на | Re: timeout on lock feature (ncm@zembu.com (Nathan Myers)) |
| Список | pgsql-hackers |
> Timeouts are a system-level mechanism that to be useful must refer to
> system-level events that are far above anything that PG knows about.
> The only way PG could apply reasonable timeouts would be for the
> application to dictate them, but the application can better implement
> them itself.
OK we have the following scenario
Session A Session B
begin begin
insert -- on unique constraint
insert -- on same unique constraint
-- Session A becomes idle
: -- Session B becomes ...
or we have (Informix Online)
Session A Session B
set lock mode to wait [seconds] set lock mode to wait [seconds]
begin begin
insert -- on unique constraint
insert -- on same unique constraint
* resource not available error *
-- Session B carries on
Oracle 7 (OCI) has oopt() call to set wait options for requested
resources. Oracle 8 OCI has the same behaviour as PG ie. oopt()
is no longer available.
I believe that the ability to switch the database to either not wait
for resources, or wait a specified period or wait forever
(default) is essential especially for interactive applications.
Regards
Theo
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