SEO

Hi,
I dont know much about databases, and I have a question

I've just installed PostgreSLQ.
Now I would like to get the number of rows selected via a ODBC SQL
statement in C++. I would like to know the amount before I do Fetch.

This is a little example of what I do in c++:

selStr="select * from layer where visible = 1");
rc = SQLAllocHandle(SQL_HANDLE_STMT, ConHandle, &StmtHandle);
if(rc == SQL_SUCCESS)
{
SQLSetStmtOption(StmtHandle, SQL_CONCURRENCY,
SQL_CONCUR_READ_ONLY);
SQLSetStmtOption(StmtHandle, SQL_CURSOR_TYPE,
SQL_CURSOR_KEYSET_DRIVEN);
SQLSetStmtOption(StmtHandle, SQL_ROWSET_SIZE, m_rows);
rc = SQLExecDirect(StmtHandle, (SQLCHAR *)selStr,
SQL_NTS);
....
....
....
How do I know how many rows that was found??


Kind regards,

Paul Malm

Hey,

I have a problem with connection of postgres.
I am using postgres 8.03.01.

I have a telecom program which have 248 channels and each channel hold a connection to postgres database, mean i have 248 opening connections.

When a channel is run, it means it begin to excute some queries to postgres, i got the error : SQL Error State: 08S01

Native Error Code: 1A

ODBC Error: Could not send
Query(connection dead);

Could not send Query(connection dead)


Could you help me on this ?


Thanks you very much
Lam






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Generally you would do that with a count function instead of relying
on something else.

"select * from layer where visible = 1"

so I guess "SELECT COUNT(*) FROM layer WHERE visible=1" would give you
the answer.

- Adam

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Hello,

Does it happen after some idle period?

Nguyen, Lam Thuy wrote:
> Hey,
>
> I have a problem with connection of postgres.
> I am using postgres 8.03.01.
>
> I have a telecom program which have 248 channels and each channel hold a connection to postgres database, mean i have 248 opening connections.
>
> When a channel is run, it means it begin to excute some queries to postgres, i got the error : SQL Error State: 08S01
>
> Native Error Code: 1A
>
> ODBC Error: Could not send
> Query(connection dead);
>
> Could not send Query(connection dead)
>
>
> Could you help me on this ?
>
>
> Thanks you very much
> Lam
>
>
>
>
>
>
> This email may contain material that is confidential, privileged, and/or attorney work product for the sole use of the intended recipient. Any review, reliance, or distribution by others or forwarding without express permission is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.
>
>


--
Andrei Kovalevski
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Managed Services, Shared and Dedicated Hosting
Co-Authors: plPHP, ODBCng - http://www.commandprompt.com/


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yes, it is right.

________________________________

From: Andrei Kovalevski [mailto:andyk@commandprompt.com]
Sent: Sun 4/6/2008 9:35 PM
To: Nguyen, Lam Thuy
Cc: Malm Paul; pgsql-odbc@postgresql.org
Subject: Re: [ODBC] Connection of postgres



Hello,

Does it happen after some idle period?

Nguyen, Lam Thuy wrote:
> Hey,
>
> I have a problem with connection of postgres.
> I am using postgres 8.03.01.
>
> I have a telecom program which have 248 channels and each channel hold a connection to postgres database, mean i have 248 opening connections.
>
> When a channel is run, it means it begin to excute some queries to postgres, i got the error : SQL Error State: 08S01
>
> Native Error Code: 1A
>
> ODBC Error: Could not send
> Query(connection dead);
>
> Could not send Query(connection dead)
>
>
> Could you help me on this ?
>
>
> Thanks you very much
> Lam
>
>
>
>
>
>
> This email may contain material that is confidential, privileged, and/or attorney work product for the sole use of the intended recipient. Any review, reliance, or distribution by others or forwarding without express permission is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.
>
>


--
Andrei Kovalevski
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Managed Services, Shared and Dedicated Hosting
Co-Authors: plPHP, ODBCng - http://www.commandprompt.com/




This email may contain material that is confidential, privileged, and/or attorney work product for the sole use of the intended recipient. Any review, reliance, or distribution by others or forwarding without express permission is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.

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Hello,

Take a look at SQLRowCount(
http://msdn2.microsoft.com/en-us/library//ms711835.aspx ). You may note:

*/For other statements and functions, the driver may define the value
returned in *RowCountPtr. For example, some data sources may be able to
return the number of rows returned by a SELECT statement or a catalog
function before fetching the rows./*

You may rely on this when using psqlODBC or ODBCng with buffering mode
ON (default).

Adam M wrote:
> Generally you would do that with a count function instead of relying
> on something else.
>
> "select * from layer where visible = 1"
>
> so I guess "SELECT COUNT(*) FROM layer WHERE visible=1" would give you
> the answer.
>
> - Adam
>
--
Andrei Kovalevski
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Managed Services, Shared and Dedicated Hosting
Co-Authors: plPHP, ODBCng - http://www.commandprompt.com/

I'm figuring similar behaviour with Linux PostgreSQL server and Win32
client, connection over Internet (not LAN). Not sure what is the source
of this problem but it could be something network relative.

Nguyen, Lam Thuy wrote:
> yes, it is right.
>
> ________________________________
>
> From: Andrei Kovalevski [mailto:andyk@commandprompt.com]
> Sent: Sun 4/6/2008 9:35 PM
> To: Nguyen, Lam Thuy
> Cc: Malm Paul; pgsql-odbc@postgresql.org
> Subject: Re: [ODBC] Connection of postgres
>
>
>
> Hello,
>
> Does it happen after some idle period?
>
> Nguyen, Lam Thuy wrote:
>
>> Hey,
>>
>> I have a problem with connection of postgres.
>> I am using postgres 8.03.01.
>>
>> I have a telecom program which have 248 channels and each channel hold a connection to postgres database, mean i have 248 opening connections.
>>
>> When a channel is run, it means it begin to excute some queries to postgres, i got the error : SQL Error State: 08S01
>>
>> Native Error Code: 1A
>>
>> ODBC Error: Could not send
>> Query(connection dead);
>>
>> Could not send Query(connection dead)
>>
>>
>> Could you help me on this ?
>>
>>
>> Thanks you very much
>> Lam
>>
>>
>>
>>
>>
>>
>> This email may contain material that is confidential, privileged, and/or attorney work product for the sole use of the intended recipient. Any review, reliance, or distribution by others or forwarding without express permission is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.
>>
>>
>>
>
>
> --
> Andrei Kovalevski
> PostgreSQL Replication, Consulting, Custom Development, 24x7 support
> Managed Services, Shared and Dedicated Hosting
> Co-Authors: plPHP, ODBCng - http://www.commandprompt.com/
>
>
>
>
> This email may contain material that is confidential, privileged, and/or attorney work product for the sole use of the intended recipient. Any review, reliance, or distribution by others or forwarding without express permission is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.
>
>


--
Andrei Kovalevski
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Managed Services, Shared and Dedicated Hosting
Co-Authors: plPHP, ODBCng - http://www.commandprompt.com/

Kovalevski ,

I am sure there was no prolem with network. I guess maybe postgres databasecan not handle if there are many connections work concurrenly.

Lam

________________________________

From: Andrei Kovalevski [mailto:andyk@commandprompt.com]
Sent: Sun 4/6/2008 10:26 PM
To: Nguyen, Lam Thuy
Cc: Malm Paul; pgsql-odbc@postgresql.org
Subject: Re: [ODBC] Connection of postgres


I'm figuring similar behaviour with Linux PostgreSQL server and Win32 client, connection over Internet (not LAN). Not sure what is the source of thisproblem but it could be something network relative.

Nguyen, Lam Thuy wrote:

yes, it is right.

________________________________

From: Andrei Kovalevski [mailto:andyk@commandprompt.com]
Sent: Sun 4/6/2008 9:35 PM
To: Nguyen, Lam Thuy
Cc: Malm Paul; pgsql-odbc@postgresql.org
Subject: Re: [ODBC] Connection of postgres



Hello,

Does it happen after some idle period?

Nguyen, Lam Thuy wrote:


Hey,

I have a problem with connection of postgres.
I am using postgres 8.03.01.

I have a telecom program which have 248 channels and each channel hold a connection to postgres database, mean i have 248 opening connections.

When a channel is run, it means it begin to excute some queries to postgres, i got the error : SQL Error State: 08S01

Native Error Code: 1A

ODBC Error: Could not send
Query(connection dead);

Could not send Query(connection dead)


Could you help me on this ?


Thanks you very much
Lam






This email may contain material that is confidential, privileged, and/or attorney work product for the sole use of the intended recipient. Any review, reliance, or distribution by others or forwarding without express permission is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.




--
Andrei Kovalevski
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Managed Services, Shared and Dedicated Hosting
Co-Authors: plPHP, ODBCng - http://www.commandprompt.com/




This email may contain material that is confidential, privileged, and/or attorney work product for the sole use of the intended recipient. Any review, reliance, or distribution by others or forwarding without express permission is strictly prohibited. If you are not the intended recipient, pleasecontact the sender and delete all copies.





--
Andrei Kovalevski
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Managed Services, Shared and Dedicated Hosting
Co-Authors: plPHP, ODBCng - http://www.commandprompt.com/

This email may contain material that is confidential, privileged, and/or attorney work product for the sole use of the intended recipient. Any review, reliance, or distribution by others or forwarding without express permission is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.

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On 07/04/2008 03:40, Nguyen, Lam Thuy wrote:

> I am sure there was no prolem with network. I guess maybe postgres
> database can not handle if there are many connections work
> concurrenly.

That's not so - if you've configured it correctly, if your hardware can
handle it, PostgreSQL scales *very* well. What have you got
max_connections set to in postgresql.conf?

Ray.


------------------------------------------------------------------
Raymond O'Donnell, Director of Music, Galway Cathedral, Ireland
rod@iol.ie
Galway Cathedral Recitals: http://www.galwaycathedral.org/recitals
------------------------------------------------------------------

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I set it up to 300.
Do you have any solution for me?

Lam

________________________________

From: Raymond O'Donnell [mailto:rod@iol.ie]
Sent: Mon 4/7/2008 11:05 AM
To: Nguyen, Lam Thuy
Cc: Andrei Kovalevski; Malm Paul; pgsql-odbc@postgresql.org
Subject: Re: [ODBC] Connection of postgres



On 07/04/2008 03:40, Nguyen, Lam Thuy wrote:

> I am sure there was no prolem with network. I guess maybe postgres
> database can not handle if there are many connections work
> concurrenly.

That's not so - if you've configured it correctly, if your hardware can
handle it, PostgreSQL scales *very* well. What have you got
max_connections set to in postgresql.conf?

Ray.


------------------------------------------------------------------
Raymond O'Donnell, Director of Music, Galway Cathedral, Ireland
rod@iol.ie
Galway Cathedral Recitals: http://www.galwaycathedral.org/recitals
------------------------------------------------------------------



This email may contain material that is confidential, privileged, and/or attorney work product for the sole use of the intended recipient. Any review, reliance, or distribution by others or forwarding without express permission is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.

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