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

From: "fanlijing" <fanlijing(at)cn(dot)fujitsu(dot)com>
To: "'Albe Laurenz'" <laurenz(dot)albe(at)wien(dot)gv(dot)at>, "'fanlijing'" <fanlijing(at)cn(dot)fujitsu(dot)com>, <pgsql-admin(at)postgresql(dot)org>
Subject: Is there any support like "for update wait N" in PostgreSQL?
Date: 2011-12-07 01:38:57
Message-ID: 262B52C2DEF844DFB1CB5C81EB02101A@fanlijing
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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?

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

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(dot)albe(at)wien(dot)gv(dot)at]

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

To: Albe Laurenz; fanlijing *EXTERN*; pgsql-admin(at)postgresql(dot)org;

pgsql-general(at)postgresql(dot)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

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