get number of rows selected

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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=3D"select * from layer where visible =3D 1");
rc =3D SQLAllocHandle(SQL_HANDLE_STMT, ConHandle, &StmtHandle);
if(rc =3D=3D 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 =3D SQLExecDirect(StmtHandle, (SQLCHAR *)selStr,
SQL_NTS);
....
....
....
How do I know how many rows that was found??

Kind regards,

Paul Malm

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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=3D"select * from layer where =
visible =3D 1");

 =
rc =3D =
SQLAllocHandle(SQL_HANDLE_STMT, ConHandle, =
&StmtHandle);

 =
if(rc =3D=3D =
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 =3D SQLExecDirect(StmtHandle, (SQLCHAR *)selStr, =
SQL_NTS);

 ...

 ...

 ...

 How do I know how =
many rows that was found??

 

Kind =
regards,


Paul =
Malm


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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 co=
nnection 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 at=
torney work product for the sole use of the intended recipient. Any review=
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ion is strictly prohibited. If you are not the intended recipient, please =
contact the sender and delete all copies.

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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.
>
>

--
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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 [at] commandprompt.com]
Sent: Sun 4/6/2008 9:35 PM
To: Nguyen, Lam Thuy
Cc: Malm Paul; pgsql-odbc [at] 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 postgr=
es, 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 revi=
ew, reliance, or distribution by others or forwarding without express permi=
ssion is strictly prohibited. If you are not the intended recipient, pleas=
e 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 at=
torney work product for the sole use of the intended recipient. Any review=
, reliance, or distribution by others or forwarding without express permiss=
ion 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/

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Hello, 
 
Take a look at SQLRowCount(
<a class="moz-txt-link-freetext" href="http://msdn2.microsoft.com/en-us/library//ms711835.aspx">http://msdn2.microsoft.com/en-us/library//ms711835.aspx</a> ). You may note: 
 
<tt>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.</tt> 
 
You may rely on this when using psqlODBC or ODBCng with buffering
mode ON (default). 
 
Adam M wrote:
<blockquote
cite="mid:84b37b360804030930o1b771e47ib9082bf3cecb54f6 [at] mail. gmail.com"
type="cite">
<pre wrap="">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
</pre>
</blockquote>
<pre class="moz-signature" cols="72">--
Andrei Kovalevski
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Managed Services, Shared and Dedicated Hosting
Co-Authors: plPHP, ODBCng - <a class="moz-txt-link-freetext" href="http://www.commandprompt.com/">http://www.commandprompt.com/</a>
</pre>
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--------------090906070702000905030802--

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--------------090803040903060905060306
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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 [at] commandprompt.com]
> Sent: Sun 4/6/2008 9:35 PM
> To: Nguyen, Lam Thuy
> Cc: Malm Paul; pgsql-odbc [at] 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/

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</head>
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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:
<blockquote
cite="mid:C3D5057033EDF145B90A99CD9025BFEA01C601FB [at] hont05.fc g.com"
type="cite">
<pre wrap="">yes, it is right.

________________________________

From: Andrei Kovalevski [<a class="moz-txt-link-freetext" href="mailto:andyk [at] commandprompt.com">mailto:andyk [at] commandprompt.com</a>]
Sent: Sun 4/6/2008 9:35 PM
To: Nguyen, Lam Thuy
Cc: Malm Paul; <a class="moz-txt-link-abbreviated" href="mailto:pgsql-odbc [at] postgresql.org">pgsql-odbc [at] postgresql.org</a>
Subject: Re: [ODBC] Connection of postgres

Hello,

Does it happen after some idle period?

Nguyen, Lam Thuy wrote:
</pre>
<blockquote type="cite">
<pre wrap="">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.

</pre>
</blockquote>
<pre wrap="">

--
Andrei Kovalevski
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Managed Services, Shared and Dedicated Hosting
Co-Authors: plPHP, ODBCng - <a class="moz-txt-link-freetext" href="http://www.commandprompt.com/">http://www.commandprompt.com/</a>

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.

</pre>
</blockquote>
 
 
<pre class="moz-signature" cols="72">--
Andrei Kovalevski
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Managed Services, Shared and Dedicated Hosting
Co-Authors: plPHP, ODBCng - <a class="moz-txt-link-freetext" href="http://www.commandprompt.com/">http://www.commandprompt.com/</a>
</pre>
</body>
</html>

--------------090803040903060905060306--

Kovalevski ,

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

Lam

________________________________

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

I'm figuring similar behaviour with Linux PostgreSQL server and Win32 clie=
nt, 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.
=09
________________________________
=09
From: Andrei Kovalevski [mailto:andyk [at] commandprompt.com]
Sent: Sun 4/6/2008 9:35 PM
To: Nguyen, Lam Thuy
Cc: Malm Paul; pgsql-odbc [at] postgresql.org
Subject: Re: [ODBC] Connection of postgres
=09
=09
=09
Hello,
=09
Does it happen after some idle period?
=09
Nguyen, Lam Thuy wrote:
=09

Hey,
=09=09
I have a problem with connection of postgres.
I am using postgres 8.03.01.
=09=09
I have a telecom program which have 248 channels and each channel hold a =
connection to postgres database, mean i have 248 opening connections.
=09=09
When a channel is run, it means it begin to excute some queries to postgr=
es, i got the error : SQL Error State: 08S01
=09=09
Native Error Code: 1A
=09=09
ODBC Error: Could not send
Query(connection dead);
=09=09
Could not send Query(connection dead)
=09=09
=09=09
Could you help me on this ?
=09=09
=09=09
Thanks you very much
Lam
=09=09
=09=09
=09=09
=09=09
=09=09
=09=09
This email may contain material that is confidential, privileged, and/or =
attorney work product for the sole use of the intended recipient. Any revi=
ew, reliance, or distribution by others or forwarding without express permi=
ssion is strictly prohibited. If you are not the intended recipient, pleas=
e contact the sender and delete all copies.
=09=09
=09=09
=09=09

--
Andrei Kovalevski
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Managed Services, Shared and Dedicated Hosting
Co-Authors: plPHP, ODBCng - http://www.commandprompt.com/
=09
=09
=09
=09
This email may contain material that is confidential, privileged, and/or a=
ttorney work product for the sole use of the intended recipient. Any revie=
w, reliance, or distribution by others or forwarding without express permis=
sion is strictly prohibited. If you are not the intended recipient, please=
contact the sender and delete all copies.
=09
=09

--
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 at=
torney work product for the sole use of the intended recipient. Any review=
, reliance, or distribution by others or forwarding without express permiss=
ion 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 [at] 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 [at] iol.ie]
Sent: Mon 4/7/2008 11:05 AM
To: Nguyen, Lam Thuy
Cc: Andrei Kovalevski; Malm Paul; pgsql-odbc [at] 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 [at] iol.ie
Galway Cathedral Recitals: http://www.galwaycathedral.org/recitals
------------------------------------------------------------ ------

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I've had a similar "problem". The connection times out and get closed
after a few hours. The solution was to do a query to keep the database
alive, for example "SELECT 1" and that's all. That is done every few
minutes.

The real test is to open 250 connections, and issue queries on each
without idle time. Does connection drop occur on active connections?

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i open connection, and leave it for few hour, and then excute query, and ge=
t error.

________________________________

From: pgsql-odbc-owner [at] postgresql.org on behalf of Adam M
Sent: Wed 4/9/2008 2:40 PM
Cc: pgsql-odbc [at] postgresql.org
Subject: Re: [ODBC] Connection of postgres

I've had a similar "problem". The connection times out and get closed
after a few hours. The solution was to do a query to keep the database
alive, for example "SELECT 1" and that's all. That is done every few
minutes.

The real test is to open 250 connections, and issue queries on each
without idle time. Does connection drop occur on active connections?

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paul malm wrote:
>
>
> 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
>
>
>

Use SQLRowCount ODBC function

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get number of rows selected

Connection of postgres

Re: get number of rows selected

Re: Connection of postgres

Re: Connection of postgres

Re: get number of rows selected

Re: Connection of postgres

Re: Connection of postgres

Re: Connection of postgres

Re: Connection of postgres

Re: Connection of postgres

Re: Connection of postgres

Re: get number of rows selected