Обсуждение: Is there any support like "for update wait N" in PostgreSQL?

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Is there any support like "for update wait N" in PostgreSQL?

От
"fanlijing"
Дата:

Hello, Laurenz

 

I'm sorry for replying you so late..

Thank you for your advice below.

Finally we decide to port it as a shell using the copy command.

 

Actually, now I'm confused with another problem, that is:

Oracle: for update wait 10

PostgreSQL: no support for the parameter "wait"

 

What should I do when I'm doing porting on this point?

If I get rid of the parameter "wait", there would be a dead lock in my program...

Is there any support like "for update wait N" in PostgreSQL?

 

Im waiting for your reply.

Thank you so much any way.

############################################################################

Following is my porting method, although it avoid the dead-lock problem, but it affect the functionality.

 

SELECT DOMAIN_ID, DOMAIN_NAME...FOR UPDATE WAIT 10 ORDER BY

->

SELECT DOMAIN_ID, DOMAIN_NAME...ORDER BY FOR UPDATE

 

 

return (List) queryBean.getQueryRun().query(queryBean.getConn(), strSql, new String[]{domain_nm,server_flag}, srHandler);

->

Connection conn = queryBean.getConn();

QueryRunner queryRunner = queryBean.getQueryRun();

queryRunner.update(conn, "set statement_timeout = 10000");

return (List) queryRunner.query(conn, strSql, new String[]{domain_nm,server_flag}, srHandler);

############################################################################

Following is the exception when run my program

 

11/12/06 15:18:17 ***: APL: INFO :

.***SqlException: ERROR: canceling statement due to statement timeout Query: SELECT ORDER BY FOR UPDATE Parameters: [yun_SF_18, 0]

       

       

11/12/06 15:18:17 ***: APL: ERROR: [ID:flj777] : !! Exception [class .***SqlException

       

       

]

############################################################################

 

Best Regards!

-----Original Message-----

From: Albe Laurenz [mailto:laurenz.albe@wien.gv.at]

Sent: Monday, October 10, 2011 10:26 PM

To: Albe Laurenz; fanlijing *EXTERN*; pgsql-admin@postgresql.org;

pgsql-general@postgresql.org

Subject: RE: [GENERAL] how to save a bytea value into a file?

 

I wrote:

[fanlijing wants to write bytea to file]

> A simple

>    COPY (SELECT byteacol WROM mytab WHERE ...) TO 'filename' (FORMAT

binary)

> should do the trick.

 

Corrections:

a) "binary" must be surrounded by single quotes.

b) that won't dump just the binary data - you would have

   to remove the first 25 bytes and the last 2 bytes...

 

So maybe using the functions I mentioned would be the

best way after all.

 

You could also write your own user defined function in C.

 

Yours,

Laurenz Albe

 

Re: Is there any support like "for update wait N" in PostgreSQL?

От
"Albe Laurenz"
Дата:
fanlijing wrote:
> Actually, now I'm confused with another problem, that is:
> Oracle: for update wait 10
> PostgreSQL: no support for the parameter "wait"
>
> What should I do when I'm doing porting on this point?
> If I get rid of the parameter "wait", there would be a dead lock in my
program...
> Is there any support like "for update wait N" in PostgreSQL?
>
> I'm waiting for your reply.
>
> Thank you so much any way.
>
>
########################################################################
####
>
> Following is my porting method, although it avoid the dead-lock
problem, but it affect the
> functionality.
>
> SELECT DOMAIN_ID, DOMAIN_NAME...FOR UPDATE WAIT 10 ORDER BY ...
> ->
> SELECT DOMAIN_ID, DOMAIN_NAME...ORDER BY ... FOR UPDATE

[...]
> queryRunner.update(conn, "set statement_timeout = 10000");
[...]
> Following is the exception when run my program...
[...]
> ....***SqlException: ERROR: canceling statement due to statement
timeout Query: SELECT... ORDER BY ... FOR
> UPDATE Parameters: [yun_SF_18, 0]

There is no "WAIT n" clause in PostgreSQL, and using statement_timeout
as
you did is the only way to get a similar functionality.

But you seem unhappy with this approach.
How does it affect the functionality?

If you use "WAIT n" in Oracle, you will get an error message (ORA-30006)
similar to using statement_timeout in PostgreSQL.

Yours,
Laurenz Albe

Re: Is there any support like "for update wait N" in PostgreSQL?

От
"fanlijing"
Дата:
Hello Laurenz

Thank you for your rapid reply.

Using statement_timeout is indeed the only-way to get a similar
functionality as "for update wait N" in oracle. It doesn't affect the
functionality at all.

As I said in the previous mail that this porting method affects the
functionality, it is finally verified as a bug in my program.

In a work, the porting method has no problem.


Sorry for interrupting you so many times.

Best Regards from a Chinese girl~ (*^__^*)

Yours,
Fan LiJing(范丽菁)
2011-12-9
-----Original Message-----
From: Albe Laurenz [mailto:laurenz.albe@wien.gv.at]
Sent: Wednesday, December 07, 2011 4:08 PM
To: fanlijing *EXTERN*; pgsql-admin@postgresql.org
Subject: RE: Is there any support like "for update wait N" in PostgreSQL?

fanlijing wrote:
> Actually, now I'm confused with another problem, that is:
> Oracle: for update wait 10
> PostgreSQL: no support for the parameter "wait"
>
> What should I do when I'm doing porting on this point?
> If I get rid of the parameter "wait", there would be a dead lock in my
program...
> Is there any support like "for update wait N" in PostgreSQL?
>
> I'm waiting for your reply.
>
> Thank you so much any way.
>
>
########################################################################
####
>
> Following is my porting method, although it avoid the dead-lock
problem, but it affect the
> functionality.
>
> SELECT DOMAIN_ID, DOMAIN_NAME...FOR UPDATE WAIT 10 ORDER BY ...
> ->
> SELECT DOMAIN_ID, DOMAIN_NAME...ORDER BY ... FOR UPDATE

[...]
> queryRunner.update(conn, "set statement_timeout = 10000");
[...]
> Following is the exception when run my program...
[...]
> ....***SqlException: ERROR: canceling statement due to statement
timeout Query: SELECT... ORDER BY ... FOR
> UPDATE Parameters: [yun_SF_18, 0]

There is no "WAIT n" clause in PostgreSQL, and using statement_timeout
as
you did is the only way to get a similar functionality.

But you seem unhappy with this approach.
How does it affect the functionality?

If you use "WAIT n" in Oracle, you will get an error message (ORA-30006)
similar to using statement_timeout in PostgreSQL.

Yours,
Laurenz Albe