[unixODBC-support] FW: can calling SQL_ATTR_CONNECTION_DEAD in SQLGetConnectAttr() result in blocking?

Antony Davies antony.davies at tmx.com
Wed Mar 13 14:36:52 GMT 2013


Hi Nick, I strace'd the  output with and without the SQLGetConnectAttr() call the  there is indeed extra IO (a write and read) on the socket which is connected to the oracle database  due to the SQLGetConnectAttr(), so it can indeed it can block since it requires an ack from the server
to determine the connection status.

Thanks for your help, Antony

From: Nick Gorham [mailto:nick at lurcher.org]
Sent: Tuesday, March 12, 2013 4:56 PM
To: Support for the unixODBC project
Cc: Antony Davies
Subject: Re: [unixODBC-support] can calling SQL_ATTR_CONNECTION_DEAD in SQLGetConnectAttr() result in blocking?

On 12/03/13 19:54, Antony Davies wrote:
Hi, is it possible for the call to block, or just it just return local state?

I have multiple threads on commit txn calls, and one on start transaction call when I
think this blocks (not 100% certain is just based on observations in a log file)

We are using version 2.2.14 of the odbc driver with oracle 10

[Oracle_ODBC_Driver]
Description     = Oracle 10g R2 ODBC driver.
Driver          = /app/oracle/product/10gR2/lib/libsqora.so.10.1
Setup           = /usr/lib64/liboraodbcS.so
FileUsage       =
CPTimeout       =
CPReuse         =

Hi,

No way of me knowing without knowing what the driver does with that call.

Maybe try running under strace/truss/dtrace and seeing what happens after the call.

--
Nick

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