Re: pg_upgrade: out of memory - Mailing list pgsql-general

Tom,

Yes, that look right for AIX . Here's the relevant section from the malloc man page ...

Return Values

       Upon successful completion, the malloc subroutine returns a pointer to space
       suitably aligned for the storage of any type of object. If the size requested is
       0, malloc returns NULL in normal circumstances. However, if the program was
       compiled with the defined _LINUX_SOURCE_COMPAT macro, malloc returns a valid
       pointer to a space of size 0.

       If the request cannot be satisfied for any reason, the malloc subroutine returns

       NULL.

Hope that helps.

Matthew

-----Original Message-----
From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
Sent: 01 October 2012 14:39
To: Carrington, Matthew (Produban)
Cc: pgsql-general@postgresql.org
Subject: Re: [GENERAL] pg_upgrade: out of memory

"Carrington, Matthew (Produban)" <Matthew.Carrington@produban.co.uk> writes:
> pg_dump: reading user-defined aggregate functions

> Breakpoint 1, exit_horribly (modulename=0x0, fmt=0x10006a590 "out of memory\n")
>     at dumputils.c:1314
> 1314    dumputils.c: A file or directory in the path name does not exist..
> (gdb) bt
> #0  exit_horribly (modulename=0x0, fmt=0x10006a590 "out of memory\n") at dumputils.c:1314
> #1  0x000000010003247c in pg_malloc (size=0) at dumpmem.c:47
> #2  0x0000000100008f54 in getAggregates (fout=0x11000bad0, numAggs=0xffffffffffff73c)
>     at pg_dump.c:3614

Oh!  Given your previous comment about there not being any user-defined
aggregates, I see what the problem is.  AIX must be one of the platforms
where malloc(0) is defined to return NULL rather than a pointer to a
zero-size block.  pg_malloc is not coping with that.

A quick fix would be

pg_malloc(size_t size)
{
    void       *tmp;

    tmp = malloc(size);
-    if (!tmp)
+    if (!tmp && size)
    {
        psql_error("out of memory\n");
        exit(EXIT_FAILURE);
    }

but I'm not sure if that's the best answer overall.  Will take it up in
-hackers.

            regards, tom lane
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