Re: C function migration from 9.2 to 9.5 - Mailing list pgsql-general

From Pavel Stehule
Subject Re: C function migration from 9.2 to 9.5
Date
Msg-id CAFj8pRB2bprBwsc6NmvhJ2KWEdG+f3mNynh40+utniALZE3oQg@mail.gmail.com
Whole thread Raw
In response to C function migration from 9.2 to 9.5  (Michael Omotayo Akinde <michaeloa@met.no>)
Responses Re: C function migration from 9.2 to 9.5  (Pavel Stehule <pavel.stehule@gmail.com>)
List pgsql-general
Hi

2016-03-03 15:12 GMT+01:00 Michael Omotayo Akinde <michaeloa@met.no>:
Hi,

We've been having a Postgresql database with some custom C functionality happily running for many years now. It's been running on 9.2, and we wish to upgrade this to the latest version. However, we're seeing some issues with the database process crashing each time.

A simplified, minimal example of the stuff that seems to get us into trouble:

It is strange. I tested your code, and it is working without any problems

compiled by gcc on Linux 64bit

Regards

Pavel
 

SQL definitions:
----

CREATE TYPE sessionData AS ( a int4, b int4, c int4 ); 

CREATE OR REPLACE FUNCTION 
__WCI_SCHEMA__.getSessionData
()
RETURNS sessionData AS
'db_libdir/db_lib', 'session_get'
LANGUAGE 'C' STABLE;

----
Function definition:
----

PG_FUNCTION_INFO_V1 (session_get);
Datum session_get(PG_FUNCTION_ARGS) {
  Datum ret = packSessionData( 0, 0, 0, fcinfo);
  return ret;
}

Datum packSessionData( int a, int b, int c, FunctionCallInfo fcinfo )
{
    TupleDesc td;
    if ( get_call_result_type( fcinfo, NULL, & td ) != TYPEFUNC_COMPOSITE )
    {
        ereport( ERROR,
                 ( errcode( ERRCODE_DATA_EXCEPTION ),
                   errmsg( "\'packSessionData\': Function returning record called in context that cannot accept type record" ) ) );
    }
    td = BlessTupleDesc( td );

    Datum * ret = ( Datum * ) palloc( 3 * sizeof( Datum ) );
    bool isNull[ 3 ] = {false, false, false};

    ret[ 0 ] = Int32GetDatum( a );
    ret[ 1 ] = Int32GetDatum( b );
    ret[ 2 ] = Int32GetDatum( c );

    HeapTuple ht = ( HeapTuple ) heap_form_tuple( td, ret, isNull );
    return HeapTupleGetDatum( ht );
}

----

Running "select getSessionData()" with this code crashes the database. Pretty much identical code worked fine in 9.2; it's only from 9.3+ we run into trouble. I'm sure we're overseeing something completely basic that has changed in 9.3, but having trouble seeing what it is. A little help would be appreciated.

Regards,

Michael A.


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