Groups > comp.databases.ms-sqlserver > #1544

Re: pitfalls of accessing linked server over WAN

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From	Erland Sommarskog <esquel@sommarskog.se>
Newsgroups	comp.databases.ms-sqlserver
Subject	Re: pitfalls of accessing linked server over WAN
Date	Wed, 21 Aug 2013 07:20:52 +0000 (UTC)
Organization	Erland Sommarskog
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migurus (migurus@yahoo.com) writes:
> The WAN is over stable dedicated circuit, but I'd like to hear what are
> potential problems here, any suggestions on how to code for those
> situations. 

Linked servers often mean hassle.

> The query will be fired with customer calling in for status, if remote
> server is not available for whatever reason I need the application to
> get 0. 

Exactly what will happen depends on whether there is a plan for the 
procedure in the cache or not. If there is no plan in the cache, and the 
remote server is not available, you will get an error when the procedure 
is compiled and the TRY block is never entered. If the plan is already in 
the cache, the TRY block is entered, but I am not sure that the error is 
caught.

In any case, for any such scenario where you want a certain behaviour 
you should test that your code behaves as expected. For a simple procedure
like this one, I would recommend that you open a direct connection 
from the application instead.

-- 
Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se

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Thread

pitfalls of accessing linked server over WAN migurus <migurus@yahoo.com> - 2013-08-20 18:31 -0700
  Re: pitfalls of accessing linked server over WAN Erland Sommarskog <esquel@sommarskog.se> - 2013-08-21 07:20 +0000
    Re: pitfalls of accessing linked server over WAN migurus <migurus@yahoo.com> - 2013-08-21 17:24 -0700
      Re: pitfalls of accessing linked server over WAN Erland Sommarskog <esquel@sommarskog.se> - 2013-08-22 08:48 +0000
  Re: pitfalls of accessing linked server over WAN Lutz <news@invalid.invalid> - 2013-08-21 10:02 +0200
    Re: pitfalls of accessing linked server over WAN migurus <migurus@yahoo.com> - 2013-08-21 17:21 -0700
      Re: pitfalls of accessing linked server over WAN Lutz <news@invalid.invalid> - 2013-08-22 08:47 +0200
        Re: pitfalls of accessing linked server over WAN bradbury9 <ray.bradbury9@gmail.com> - 2013-08-22 00:10 -0700
        Re: pitfalls of accessing linked server over WAN migurus <migurus@yahoo.com> - 2013-08-22 11:32 -0700

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