Re: How to fix 0xC0000005 exception in Postgres 9.0

On 2/21/20 10:24 AM, Andrus wrote:
> Hi!
>
>> forgot to say publish the Linux logs it may have more details what is
>> going on
>
> Linux server has older application client which replicates all data one
> from andmetp table using select * from andmetp
> I tried several times. Linux log contains
>
> 2020-02-21 16:18:50 EET mydbadmin mydb STATEMENT:  SELECT * FROM andmetp
> 2020-02-21 16:18:50 EET mydbadmin mydb FATAL:  connection to client lost
> 2020-02-21 16:18:50 EET mydbadmin mydb STATEMENT:  SELECT * FROM andmetp
> 2020-02-21 17:19:08 EET mydbadmin mydb LOG:  could not send data to
> client: Connection reset by peer
> 2020-02-21 17:19:08 EET mydbadmin mydb STATEMENT:  SELECT * FROM andmetp
> 2020-02-21 17:19:08 EET mydbadmin mydb FATAL:  connection to client lost
> 2020-02-21 17:19:08 EET mydbadmin mydb STATEMENT:  SELECT * FROM andmetp
>
> It looks like only connection was terminated.  “dmesg -T” does not show
> postgres crash. Maybe postgres main process is not killed in Linux.
>
>> is this happening from any client or just a specific client running ODBC?
>
> This happene if Windows 2008 server if logged in same same server from
> RDP client and in my development windows 10 workstation which logs to
> linux server over VPN
>
>> are the clients running AV if so are the AV versions the same?
>
> In windows 2008 server antivirus was turned off like I wrote.  In my
> devel workstation I use Microsoft antivirus coming with windows 10.
>
>> Given this is killing a Linux server,  sounds like ODBC is sending
>> back garabage data to the server crashing it.
>
> I can try publish odbc log if this helps.
>
> Application replicateds some tables at startup to local disk.
> For tables with 5000 or more rows odbc connection hangs if there is big
> TCP packet loss.
> So we changed  replication command
>
> select * from mytable
>
> to commands
>
> select drop_table(‘temptulemus’);
> create temp table  tempestuous as select * from mytable;
>
> select * from mytable offset 0 limit 900;
> select * from mytable offset 900 limit 900;
> select * from mytable offset 1800 limit 900;
> ...
>
> etc.
>
> In this case data was also retrieved on poor connections.
> Maybe there is some better solution for this.
>
>> There are several settings in OBDC, to change how text columns are
>> processed, play around with those settings see if that helps it
>> https://odbc.postgresql.org/docs/config.html
>
> Application needs certain settings. Maybe it is better try to upgrade to
> Postgres 12.2 first.
>
>> As you have it narrowed down to a table,  try querying only a few
>> records at a time to see if you can identify the specific Record(s)
>> that may be the issue.
>> SELECT * FROM temptulemus where temptulemus.unique_id >1  offset 0
>> limit 100
>> and try querying the columns that do not contain the suspect data that
>> could be causing this
>
> andmetp table contains 584 record in linux server. I tried script to
> read data from this table every time one more row

In psql what does \d tempestuous show?

What relation is andmetp to tempestuous?

I thought you said you had problem with same table in Linux and Windows
servers?

From above what does the drop_table() function do in?:

select drop_table(‘temptulemus’);

>
> for i=1 to 600
> ? i
> StartTextMerge()
> TEXT TEXTMERGE NOSHOW
> select * from andmetp limit <<tran(i)>>
> ENDTEXT
> IF !TExec()
>  RETURN .f.
>  ENDIF
> endfor
>
> this worked without error.
>
> Andrus.

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com