Socket command type unknown

Hi Al,

I am sending this mail to Postgresql interface list as this involves libpq.so.
I am not very sure the problem lies in the library. But wanted to post
the query and know what needs to be done.

Postgresql: postgresql-7.2.1-5
Linux: 7.3 Kernel 2.4.19
DBD::Pg: DBD-Pg-1.22-0
DBI: DBI-1.30-0
eRserver: erserver-1.2-3

We are using eRserver for database replication. The erserver first needs to be setup.
The setup script creates the following table.

create table _RSERV_TABLES_ (tname name, cname name, reloid oid, key int4)

The table creation is exiting. Enabling syslog of Postgresql we found that
postgres backend process is exiting with error "Socket command type N unknown".
We know what the error means. But we are unable to trace the problem cause.

NOTE that, this invalid command type problem comes only some times. Most
of the time the create table succeeds.

The following is the trace of DBD::Pg sender followed by the syslog messages (We have
put this messages in postgres and compiled the code) of postgres process.

We can clearly see that postgres is receiving the NOTICE message back
which it sent to DBD::Pg.

We have browsed both the sender and receiver code. Both have been written to follow
the protocol of query sending i.e. Send "Q" followed by the query string.

However, its surprise here as to how postgres socket recieved the NOTICE it sent
to DBD::Pg.

If we look at the log of DBD::Pg sender. It does not show that it sent something
wrong to Postgres.

This leaves the question as to how Postgres received it.

We have visted the mail thread on such problem and DBD::Pg site suggests
that it may be Pearl problem. However we could not guess how Pearl could
impact it.

PLEASE LET US KNOW HOW THIS SOCKET PROBLEM CAN BE RESOLVED. WE WOULD
BE THANKFUL FOR ALL THE REPLIES.

DBD::Pg SENDER:
--------------
dbd_st_preparse: statement = >create table _RSERV_TABLES_ (tname name, cname name, reloid

oid, key int4)<
1 <- prepare= DBI::st=HASH(0x82355c8) at /usr/lib/perl5/site_perl/5.6.1/i386-linux/DBI.pm

line 1212 via /usr/local/erserver/bin/ers_setup line 153
>> execute DISPATCH (DBI::st=HASH(0x82355c8) rc1/1 @1 g0 ima41 pid#20233) at

/usr/lib/perl5/site_perl/5.6.1/i386-linux/DBI.pm line 1213 via

/usr/local/erserver/bin/ers_setup line 153
-> execute for DBD::Pg::st (DBI::st=HASH(0x82355c8)~0x827deec)
dbd_st_execute
dbd_st_execute: statement = >create table _RSERV_TABLES_ (tname name, cname name, reloid

oid, key int4)<
FATAL 1: Socket command type N unknown error 7 recorded: FATAL 1: Socket command type N

unknown
!! ERROR: 7 'FATAL 1: Socket command type N unknown'
<- execute= undef at /usr/lib/perl5/site_perl/5.6.1/i386-linux/DBI.pm line 1213 via

/usr/local/erserver/bin/ers_setup line 153
!! ERROR: 7 'FATAL 1: Socket command type N unknown'
<- do= undef at /usr/local/erserver/bin/ers_setup line 153
>> errstr DISPATCH (DBI::db=HASH(0x82173f8) rc1/1 @1 g1 ima4 pid#20233) at

/usr/local/erserver/bin/ers_setup line 153
>> errstr DISPATCH (DBI::db=HASH(0x82173f8) rc1/1 @1 g1 ima4 pid#20233) at

/usr/local/erserver/bin/ers_setup line 153
-> errstr in DBD::_::common for DBD::Pg::db (DBI::db=HASH(0x82173f8)~0x82174ac)
<- errstr= ( 'FATAL 1: Socket command type N unknown' ) [1 items] at

/usr/local/erserver/bin/ers_setup line 153
>> DESTROY DISPATCH (DBI::db=HASH(0x82173f8) rc1/1 @1 g0 ima0 pid#20233)
<> DESTROY ignored for outer handle DBI::db=HASH(0x82173f8) (inner

DBI::db=HASH(0x82174ac))
>> DESTROY DISPATCH (DBI::db=HASH(0x82683e8) rc1/1 @1 g0 ima0 pid#20233)
<> DESTROY ignored for outer handle DBI::db=HASH(0x82683e8) (inner

DBI::db=HASH(0x8208a4c))

Postgres RECEIVER
-----------------
Apr 29 19:19:08 cp_node2 cpdb cpdb 10.1.1.2 idle in transaction: Postgres Recv <Q

create table _RSERV_SERVERS_ (server serial, host text,

post int4, dbase text)>
Apr 29 19:19:08 cp_node2 cpdb cpdb 10.1.1.2 idle in transaction: Postgres Recv 124
Apr 29 19:19:08 cp_node2 cpdb cpdb 10.1.1.2 idle in transaction: Postgres Recv <NOTICE:

CREATE TABLE will create implicit sequence '_rserv_servers__server_seq' for SERIAL column

'_rserv_servers_.server' NOTICE: CREATE TABLE / UNIQUE will create implicit index

'_rserv_servers__server_key' for table '_rserv_servers_' >
Apr 29 19:19:08 cp_node2 cpdb cpdb 10.1.1.2 idle in transaction: Postgres Recv 239
Apr 29 19:19:08 cp_node2 cpdb cpdb 10.1.1.2 idle in transaction: Postgres Recv <Qrollback>
Apr 29 19:19:08 cp_node2 cpdb cpdb 10.1.1.2 idle in transaction: Postgres Recv 9

Thanks
Prasad

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