Bug #933: Too many inserts crash server

Mark Pether (mutex(at)redsheriff(dot)com) reports a bug with a severity of 2
The lower the number the more severe it is.

Short Description
Too many inserts crash server

Long Description
If I create an external C function consisting of a
simple loop that inserts 250000 records into a table
the server process eventually crashes.

Actually the number of inserts appears to be dependant
upon memory consumption by SPI manager. (so your milage
may vary)

The workaround I found involves periodically calling
SPI_finish + SPI_connect to bounce the manager.

I have included code to illustrate the problem and my workaround.

My platform is:
Intel P3
Mandrake 8.2
512mb RAM
Postgres 7.3
plenty of disk free.

Sample Code
postgres initialisation:

create table triple (a int, b int, c int);
create or replace function crashme() returns void as 'pgtest.so' language 'c';
create or replace function dontcrashme() returns void as 'pgtest.so' language 'c';

the code:

#include <string.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <time.h>
#include "avl.h"
#include "postgres.h"
#include "fmgr.h"
#include "executor/spi.h"
#include "utils/date.h"
#include "utils/datetime.h"

Datum crashme(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(crashme);
Datum crashme(PG_FUNCTION_ARGS)
{
const char *DEBUG_NAME = "crashme(): ";

char *query = "insert into triple values (100, 200, 300)";

if (SPI_connect() == SPI_OK_CONNECT)
{
int i;
int exec_result;

for (i=0; i<250000; i++)
{
if (!(i%16384))
{
elog(INFO, "%sstill alive", DEBUG_NAME);
}

if ((exec_result = SPI_exec(query, 0)) != SPI_OK_INSERT)
{
elog(ERROR, "%sinsert failed (%d)", DEBUG_NAME, exec_result);
break;
}
}

SPI_finish();
}
else
{
elog(ERROR, "%scould not connect", DEBUG_NAME);
}

PG_RETURN_NULL();
}

Datum dontcrashme(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(dontcrashme);
Datum dontcrashme(PG_FUNCTION_ARGS)
{
const char *DEBUG_NAME = "dontcrashme(): ";

char *query = "insert into triple values (100, 200, 300)";

if (SPI_connect() == SPI_OK_CONNECT)
{
int i;
int exec_result;

for (i=0; i<250000; i++)
{
if (!(i%16384))
{
elog(INFO, "%sbouncing SPI manager", DEBUG_NAME);
elog(INFO, "%sSPI_finish (%s)",
DEBUG_NAME, (SPI_finish() == SPI_OK_FINISH) ? "good" : "bad");
elog(INFO, "%sSPI_connect (%s)",
DEBUG_NAME, (SPI_connect() == SPI_OK_CONNECT) ? "good" : "bad");
}

if ((exec_result = SPI_exec(query, 0)) != SPI_OK_INSERT)
{
elog(ERROR, "%sinsert failed (%d)", DEBUG_NAME, exec_result);
break;
}
}

SPI_finish();
}
else
{
elog(ERROR, "%scould not connect", DEBUG_NAME);
}

PG_RETURN_NULL();
}

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