pika failing since the per-column collation patch

On lör, 2011-02-12 at 13:34 +0100, Rémi Zara wrote:

Since the per-column collation patch went in, pika (NetBSD 5.1/mips) started failing consistently with this diff:

*** /home/pgbuildfarm/workdir/HEAD/pgsql.15101/src/test/regress/expected/polymorphism.out	Sat Feb 12 02:16:07 2011
--- /home/pgbuildfarm/workdir/HEAD/pgsql.15101/src/test/regress/results/polymorphism.out	Sat Feb 12 09:10:21 2011
***************
*** 624,630 ****

-- such functions must protect themselves if varying element type isn't OK
select max(histogram_bounds) from pg_stats;
! ERROR:  cannot compare arrays of different element types
-- test variadic polymorphic functions
create function myleast(variadic anyarray) returns anyelement as $$
select min($1[i]) from generate_subscripts($1,1) g(i)
--- 624,630 ----

-- such functions must protect themselves if varying element type isn't OK
select max(histogram_bounds) from pg_stats;
! ERROR: locale operation to be invoked, but no collation was derived
-- test variadic polymorphic functions
create function myleast(variadic anyarray) returns anyelement as $$
select min($1[i]) from generate_subscripts($1,1) g(i)

Is there something I can do to help investigate this ?

It's only failing on this one machine, but there isn't anything
platform-specific in this code, so I'd look for memory management faults
on the code or a compiler problem. Try with lower optimization for a
start.

Le 12 févr. 2011 à 18:51, Peter Eisentraut a écrit :

On lör, 2011-02-12 at 13:34 +0100, Rémi Zara wrote:

Since the per-column collation patch went in, pika (NetBSD 5.1/mips) started failing consistently with this diff:

*** /home/pgbuildfarm/workdir/HEAD/pgsql.15101/src/test/regress/expected/polymorphism.out	Sat Feb 12 02:16:07 2011
--- /home/pgbuildfarm/workdir/HEAD/pgsql.15101/src/test/regress/results/polymorphism.out	Sat Feb 12 09:10:21 2011
***************
*** 624,630 ****

-- such functions must protect themselves if varying element type isn't OK
select max(histogram_bounds) from pg_stats;
! ERROR:  cannot compare arrays of different element types
-- test variadic polymorphic functions
create function myleast(variadic anyarray) returns anyelement as $$
select min($1[i]) from generate_subscripts($1,1) g(i)
--- 624,630 ----

-- such functions must protect themselves if varying element type isn't OK
select max(histogram_bounds) from pg_stats;
! ERROR: locale operation to be invoked, but no collation was derived
-- test variadic polymorphic functions
create function myleast(variadic anyarray) returns anyelement as $$
select min($1[i]) from generate_subscripts($1,1) g(i)

Is there something I can do to help investigate this ?

It's only failing on this one machine, but there isn't anything
platform-specific in this code, so I'd look for memory management faults
on the code or a compiler problem. Try with lower optimization for a
start.

Same failure with -O0 (and more shared memory).

Regards,

Rémi Zara

Le 14 févr. 2011 à 19:27, Rémi Zara a écrit :

Le 12 févr. 2011 à 18:51, Peter Eisentraut a écrit :

It's only failing on this one machine, but there isn't anything
platform-specific in this code, so I'd look for memory management faults
on the code or a compiler problem. Try with lower optimization for a
start.

Same failure with -O0 (and more shared memory).

Hi,

Without me changing anything (still at -O0), the same error occurred but at the installCheck step, rather than the check step (which passed)

Anything else to try ?

Regards,

Rémi Zara

Le 14 févr. 2011 à 19:27, Rémi Zara a écrit :

Le 12 févr. 2011 à 18:51, Peter Eisentraut a écrit :

It's only failing on this one machine, but there isn't anything
platform-specific in this code, so I'd look for memory management faults
on the code or a compiler problem. Try with lower optimization for a
start.

Same failure with -O0 (and more shared memory).

Hi,

Without me changing anything (still at -O0), the same error occurred but at the installCheck step, rather than the check step (which passed)

Anything else to try ?

Regards,

Rémi Zara

=?iso-8859-1?Q?R=E9mi_Zara?= <remi_zara@mac.com> writes:

Le 12 f�vr. 2011 � 18:51, Peter Eisentraut a �crit :

It's only failing on this one machine, but there isn't anything
platform-specific in this code, so I'd look for memory management faults
on the code or a compiler problem. Try with lower optimization for a
start.

Same failure with -O0 (and more shared memory).

Note that the query that is failing is an intentional probe of
robustness:

-- check that we can apply functions taking ANYARRAY to pg_stats ...
-- such functions must protect themselves if varying element type isn't OK
select max(histogram_bounds) from pg_stats;
ERROR: cannot compare arrays of different element types

pika is instead showing

ERROR: locale operation to be invoked, but no collation was derived

which some trawling through the code says is coming from varstr_cmp
when fn_collation didn't get set on the call.

Hypothesis: the platform-dependency here is just one of row ordering,
to wit, on most platforms the scan of pg_statistic fails before it gets
to the case where the collation issue is triggered. I'm suspicious that
if two text arrays get compared via this code path, fn_collation fails
to get set, and it's not a platform-specific omission.

It'd be helpful if you could identify the specific values that are
getting compared at the moment of the failure.

regards, tom lane

Le 18 févr. 2011 à 08:26, Tom Lane a écrit :

=?iso-8859-1?Q?R=E9mi_Zara?= <remi_zara@mac.com> writes:

Le 12 févr. 2011 à 18:51, Peter Eisentraut a écrit :

It's only failing on this one machine, but there isn't anything
platform-specific in this code, so I'd look for memory management faults
on the code or a compiler problem. Try with lower optimization for a
start.

Same failure with -O0 (and more shared memory).

Note that the query that is failing is an intentional probe of
robustness:

-- check that we can apply functions taking ANYARRAY to pg_stats ...
-- such functions must protect themselves if varying element type isn't OK
select max(histogram_bounds) from pg_stats;
ERROR: cannot compare arrays of different element types

pika is instead showing

ERROR: locale operation to be invoked, but no collation was derived

which some trawling through the code says is coming from varstr_cmp
when fn_collation didn't get set on the call.

Hypothesis: the platform-dependency here is just one of row ordering,
to wit, on most platforms the scan of pg_statistic fails before it gets
to the case where the collation issue is triggered. I'm suspicious that
if two text arrays get compared via this code path, fn_collation fails
to get set, and it's not a platform-specific omission.

It'd be helpful if you could identify the specific values that are
getting compared at the moment of the failure.

Hi,

Here is what I get after adding an elog in varstr_cmp:

WARNING: Comparing "B011 " and "<fetch first clause> in subqueries^?^?\xa0"
ERROR: locale operation to be invoked, but no collation was derived
STATEMENT: select max(histogram_bounds) from pg_stats;

Regards,

Rémi Zara