Thread: An INSERT can kill the PostgreSQL server

Your name        :    Richi Plana
Your email address    :    richip@mozcom.com


System Configuration
---------------------
  Architecture (example: Intel Pentium)      :   Intel PentiumIII-500

  Operating System (example: Linux 2.0.26 ELF)     :   Linux 2.2.15 ELF

  PostgreSQL version (example: PostgreSQL-6.5.1):   PostgreSQL-7.0

  Compiler used (example:  gcc 2.8.0)        :   gcc 2.91.66


Please enter a FULL description of your problem:
------------------------------------------------
While INSERTing a row into a TABLE, the backend would die and restart


Please describe a way to repeat the problem.   Please try to provide a
concise reproducible example, if at all possible:
----------------------------------------------------------------------
Table defs:

create table devices (brand varchar(30), model varchar(30), serial
varchar(30), ro_community varchar(50)[], rw_community varchar(50)[], primary
key (brand, model, serial));

create table routers (lo_address inet) inherits (devices);

Query:

insert into routers values ('Cisco', '7206VXR', '72498595', '{"Butterflies",
"Intehsoijfeijfjf"}', NULL, '10.2.3.4');


If you know how this problem might be fixed, list the solution below:
---------------------------------------------------------------------

--

L   L Richi Plana, CCNA 8^)   ,-,-.     ,-,-.     ,-,-.     ,-,-.     ,-
LL LL Systems Administrator  / / \ \   / / \ \   / / \ \   / / \ \   / /
LLLLL Mosaic Communications, Inc. \ \ / /   \ \ / /   \ \ / /   \ \ / /
LLLLL mailto:richip@mozcom.com     `-'-'     `-'-'     `-'-'     `-'-'

Richi Plana <richip@mozcom.com> writes:
> create table devices (brand varchar(30), model varchar(30), serial
> varchar(30), ro_community varchar(50)[], rw_community varchar(50)[], primary
> key (brand, model, serial));
> create table routers (lo_address inet) inherits (devices);
> insert into routers values ('Cisco', '7206VXR', '72498595', '{"Butterflies",
> "Intehsoijfeijfjf"}', NULL, '10.2.3.4');

Hmm.  Looks like there is some kind of unpleasant interaction between
the constant-expression simplifier and application of array-element
length constraints.  Thanks for the report, I'll look into it today.

If you are in a *big* hurry, I expect declaring rw_community as
text[] would avoid the bug.

            regards, tom lane

Richi Plana <richip@mozcom.com> writes:
> create table devices (brand varchar(30), model varchar(30), serial
> varchar(30), ro_community varchar(50)[], rw_community varchar(50)[], primary
> key (brand, model, serial));

> create table routers (lo_address inet) inherits (devices);

> insert into routers values ('Cisco', '7206VXR', '72498595', '{"Butterflies",
> "Intehsoijfeijfjf"}', NULL, '10.2.3.4');

Ah, I see it: it's the NULL array value that is causing the problem.
6.5 parser didn't really handle the NULL properly, but 7.0's does:
it tries to apply array_map() to the NULL to ensure it's coerced to
50-chars-per-item length limit.  Which means array_map had better be
NULL-proof.

This patch is applied for 7.0.1, but if you need a fix now:

*** src/backend/utils/adt/arrayfuncs.c~    Wed Jan 26 00:57:12 2000
--- src/backend/utils/adt/arrayfuncs.c    Sun May 28 13:43:34 2000
***************
*** 1308,1313 ****
--- 1308,1317 ----
      char       *s;
      char       *p;
      va_list        ap;
+
+     /* Need to guard against NULL input array */
+     if (v == NULL)
+         return NULL;

      /* Large objects not yet supported */
      if (ARR_IS_LO(v) == true)



            regards, tom lane