Thread: Ответ: [HACKERS] Otvet: WAL and indexes (Re: [HACKERS] WAL status & todo)

>> One of the purposes of WAL is immediate removing tuples
>> inserted by aborted xactions. I want make VACUUM
>> *optional* in future - space must be available for
>> reusing without VACUUM. And this is first, very small,
>> step in this direction.
>
>Why would vacuum become optional?  Would WAL offer an option to
>not reclaim free space?  We're hoping that vacuum becomes unneeded

Reclaiming free space is issue of storage manager, as
I said here many times. WAL is just Write A-head Log
(first write to log then to data files, to have ability
to recover using log data) and for matter of space it can
only help to delete tuples inserted by aborted transaction.

>when postgresql is run with some flag indicating that we're
>uninterested in time travel.

Time travel is gone ~ 3 years ago and vacuum was needed all
these years and will be needed to reclaim space in 7.1

>How much longer do you estimate until you can make it work that way?

Hopefully in 7.2

Vadim

"Mikheev, Vadim" wrote:

> >> One of the purposes of WAL is immediate removing tuples
> >> inserted by aborted xactions. I want make VACUUM
> >> *optional* in future - space must be available for
> >> reusing without VACUUM. And this is first, very small,
> >> step in this direction.
> >
> >Why would vacuum become optional?  Would WAL offer an option to
> >not reclaim free space?  We're hoping that vacuum becomes unneeded
>
> Reclaiming free space is issue of storage manager, as
> I said here many times. WAL is just Write A-head Log
> (first write to log then to data files, to have ability
> to recover using log data) and for matter of space it can
> only help to delete tuples inserted by aborted transaction.
>
> >when postgresql is run with some flag indicating that we're
> >uninterested in time travel.
>
> Time travel is gone ~ 3 years ago and vacuum was needed all
> these years and will be needed to reclaim space in 7.1
>
> >How much longer do you estimate until you can make it work that way?
>
> Hopefully in 7.2
>

Just a confirmation.
Do you plan overwrite storage manager also in 7.2 ?

Hiroshi Inoue