On Mon, 17 Feb 2003 09:51:54 +0800, "Christopher Kings-Lynne"
<[EMAIL PROTECTED]> wrote:
>Strategy three:
>
>begin;
>lock table in exclusive mode;
>update row;
>if (no rows affected) insert row;
>commit;
>
>Problem - Works, but this table needs high concurrency.
Chris,
distributing congestion mig
Hi,
Vincent van Leeuwen wrote, On 2/19/2003 10:08 PM:
On 2003-02-18 20:02:29 +0100, Peter Eisentraut wrote:
Christopher Kings-Lynne writes:
> REPLACE INTO anyone? ;)
The upcoming SQL 200x standard includes a MERGE command that appears to
fulfill that purpose.
MySQL features a poor-mans apro
On 2003-02-18 20:02:29 +0100, Peter Eisentraut wrote:
> Christopher Kings-Lynne writes:
>
> > REPLACE INTO anyone? ;)
>
> The upcoming SQL 200x standard includes a MERGE command that appears to
> fulfill that purpose.
>
MySQL features a poor-mans aproach to this problem, their REPLACE command:
Christopher Kings-Lynne writes:
> *sigh* It's just like a standard to come up with a totally new syntax for a
> feature that no-one has except MySQL who use a different syntax :)
Actually that command was copied straight out of Oracle.
--
Peter Eisentraut [EMAIL PROTECTED]
-
Christopher Kings-Lynne wrote:
>
>*sigh* It's just like a standard to come up with a totally new syntax for a
>feature that no-one has except MySQL who use a different syntax :)
You sure? :)
http://otn.oracle.com/products/oracle9i/daily/Aug24.html
MERGE INTO SALES_FACT D
USING SALES_JUL
URL added to develepers FAQ.
---
Peter Eisentraut wrote:
> Hannu Krosing writes:
>
> > Where is this upcoming standard available on net ?
>
> Near ftp://sqlstandards.org/SC32/WG3/Progression_Documents/FCD
>
> --
> Peter
> > REPLACE INTO anyone? ;)
>
> The upcoming SQL 200x standard includes a MERGE command that appears to
> fulfill that purpose.
Is there somewhere that I can read that spec?
Or can you just post the MERGE syntax for us?
*sigh* It's just like a standard to come up with a totally new syntax for a
Hannu Krosing writes:
> Where is this upcoming standard available on net ?
Near ftp://sqlstandards.org/SC32/WG3/Progression_Documents/FCD
--
Peter Eisentraut [EMAIL PROTECTED]
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TIP 1: subscribe and unsubscribe commands
Peter Eisentraut kirjutas T, 18.02.2003 kell 21:02:
> Christopher Kings-Lynne writes:
>
> > REPLACE INTO anyone? ;)
>
> The upcoming SQL 200x standard includes a MERGE command that appears to
> fulfill that purpose.
Where is this upcoming standard available on net ?
Hannu
---
e; Hackers
Subject: Re: [HACKERS] Hard problem with concurrency
Christopher Kings-Lynne writes:
> REPLACE INTO anyone? ;)
The upcoming SQL 200x standard includes a MERGE command that appears to
fulfill that purpose.
--
Peter Eisentraut [EMAIL PROTECTED]
---(end
Christopher Kings-Lynne writes:
> REPLACE INTO anyone? ;)
The upcoming SQL 200x standard includes a MERGE command that appears to
fulfill that purpose.
--
Peter Eisentraut [EMAIL PROTECTED]
---(end of broadcast)---
TIP 6: Have you searched our
Christopher Kings-Lynne wrote:
> > If you don't have a primary key already, create a unique index on the
> > combination you want to be unique. Then:
> >
> > . Try to insert the record
> > . If you get a duplicate key error
> > then do update instead
> >
> > No possibilities of duplicate records
On Sun, Feb 16, 2003 at 23:51:49 -0500,
Greg Stark <[EMAIL PROTECTED]> wrote:
>
> Hm, odd, nobody mentioned this solution:
>
> If you don't have a primary key already, create a unique index on the
> combination you want to be unique. Then:
>
> . Try to insert the record
> . If you get a duplic
> If you don't have a primary key already, create a unique index on the
> combination you want to be unique. Then:
>
> . Try to insert the record
> . If you get a duplicate key error
> then do update instead
>
> No possibilities of duplicate records due to race conditions. If two
people
> try to
Hm, odd, nobody mentioned this solution:
If you don't have a primary key already, create a unique index on the
combination you want to be unique. Then:
. Try to insert the record
. If you get a duplicate key error
then do update instead
No possibilities of duplicate records due to race condit
> Do the update, then try to insert if the update found nothing, and put
> a retry loop around the whole transaction in case you fail because of
> concurrent inserts.
>
> Realistically you will need a retry loop in all but the most trivial
> cases anyway --- certainly so if you want to use serializ
"Christopher Kings-Lynne" <[EMAIL PROTECTED]> writes:
> I can't try the insert and then the update because the INSERT, in Postgres,
> will cause an outright transaction failure.
Do the update, then try to insert if the update found nothing, and put
a retry loop around the whole transaction in case
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Hash: SHA1
Solution one: use sequences for the unique value.
Solution two: use another table to effect the exclusive locking
and use it to store the "unique" values:
begin;
update row;
if (no rows affected) {
lock table foo in exclusive mode;
find a uniq
OK, this is the problem:
I want to write a bit of SQL that if a row exists in a table, then update
it, otherwise it will update it. Problem is, there is a very high chance of
simultaneous execute of this query on the same row (the rows have a unique
index).
So, strategy one:
begin;
update row;
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