[dabo-users] postgres pkid before commit

> On 5/3/12 9:06 PM, Vineet Deodhar wrote:

> > Isn't it dangerous to get a pkid from the db before commit?

> > Consider a situation where UserA gets a pkid "2564' for a table "tbl1".

> > Before this change is committed, UserB inserts a record to tbl1& gets

> > "2564".

> >

> > Wouldn't is cause a mess?

> No, postgres knows it handed out 2564 already, even though it isn't

> committed yet.

> Paul

I see.

In that case, it would lead to further trouble such as -->

UserA, after getting pkid 2564 for tbl1, cancels the addition.

So 5264 is unutilized.

If the no. of users & data-traffic is quite low, no issue.

But consider a case where hundreds of users are interacting with tbl1 and

there are a lot of cases for cancelled additions to tbl1.

In effect, even if the smallint data-type for this pkid is sufficient, the

DBA has to opt for maybe mediumint !

Anyway, I am using MySQL and I am very much comfortable with it.

-- Vineet

> > Postgres can provide the PK from a record before it is committed.

> >

> > transaction

> > begin

> > insert record

> > retrieve PK (I will assume that is a serial data type).

> > insert record

> > retrieve PK

> > continue

> >

> > commit or rollback

> >

> > I realize that Dabo does not do it but I do it all the time with Dabo

> temp

> > cursors.

> >

> > Johnf

--- StripMime Report -- processed MIME parts ---

multipart/alternative

text/plain (text body -- kept)

text/html

---

_______________________________________________

Post Messages to: Dabo-users@leafe.com