> > For each page hit, I do this:
> >
> > update pagecounts set counter = counter + 1 where pagename =
> 'testpag.php'
> >
> > Do I have to set a particular isolation level? Or does this not work in
> > general?
>
> In read committed level, if the second update launches before the first
> update
Tom Lane wrote:
>
> Peter Eisentraut <[EMAIL PROTECTED]> writes:
> > Tom Lane writes:
> To my mind, full SERIALIZABLE mode is the only approach that can be
> explained in terms of simple notions like "you see only the data that
> existed at time T".
There's another way. If the current value is d
Peter Eisentraut <[EMAIL PROTECTED]> writes:
> Tom Lane writes:
>> The reason it works in read-committed mode is that the second guy to
>> arrive at the row will observe that the row has an update in progress;
>> will block waiting for the previous updater to commit or abort; and if
>> commit, wil
Tom Lane writes:
> The reason it works in read-committed mode is that the second guy to
> arrive at the row will observe that the row has an update in progress;
> will block waiting for the previous updater to commit or abort; and if
> commit, will use the updated version of the row as the starti
Take this update statement:
update mytable set foo=foo+1 where bar='xxx';
If that gets executed more than once at the same time by multiple instances of
postgresql. Will foo ever lose a count?
I am assumed that foo will always be correct and that the database will manage
any contention, but wh
mlw <[EMAIL PROTECTED]> writes:
> I'm not sure you answered my question. Let me put it to you like this:
> Suppose I wanted to make a table of page counts, like this:
> create table pagecounts (counter int4, pagename varchar)
> For each page hit, I do this:
> update pagecounts set counter = counte
mlw writes:
> For each page hit, I do this:
>
> update pagecounts set counter = counter + 1 where pagename = 'testpag.php'
>
> Do I have to set a particular isolation level? Or does this not work in
> general?
In read committed level, if the second update launches before the first
update is fini
Peter Eisentraut wrote:
>
> mlw writes:
>
> > update mytable set foo=foo+1 where bar='xxx';
> >
> > If that gets executed more than once at the same time by multiple instances of
> > postgresql. Will foo ever lose a count?
>
> No, but if you run this in read committed isolation mode then you mi
mlw writes:
> update mytable set foo=foo+1 where bar='xxx';
>
> If that gets executed more than once at the same time by multiple instances of
> postgresql. Will foo ever lose a count?
No, but if you run this in read committed isolation mode then you might
get into non-repeatable read type probl
Take this update statement:
update mytable set foo=foo+1 where bar='xxx';
If that gets executed more than once at the same time by multiple instances of
postgresql. Will foo ever lose a count?
I am assumed that foo will always be correct and that the database will manage
any contention, but w
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