Обсуждение: BUG #8399: inconsistent input of multidimensional arrays
The following bug has been logged on the website:
Bug reference: 8399
Logged by: Alexey Borzov
Email address: borz_off@cs.msu.su
PostgreSQL version: 9.3rc1
Operating system: irrelevant
Description:
PostgreSQL documentation states:
"Multidimensional arrays must have matching extents for each dimension. A
mismatch causes an error..."
This is not completely true:
postgres=# select cast('{{1,2}, {3}}' as integer[]);
ERROR: multidimensional arrays must have array expressions with matching
dimensions
LINE 1: select cast('{{1,2}, {3}}' as integer[]);
^
postgres=# select cast('{{1}, {2,3}}' as integer[]);
int4
------------------
{{1,NULL},{2,3}}
(1 row)
Trying to use an array constructor yields an expected error in both cases.
Confirmed on 9.3rc1 and 9.0.13
On Tue, Aug 27, 2013 at 08:18:10AM +0000, borz_off@cs.msu.su wrote:
> PostgreSQL documentation states:
>
>
> "Multidimensional arrays must have matching extents for each dimension. A
> mismatch causes an error..."
>
>
> This is not completely true:
> postgres=# select cast('{{1,2}, {3}}' as integer[]);
> ERROR: multidimensional arrays must have array expressions with matching
> dimensions
> LINE 1: select cast('{{1,2}, {3}}' as integer[]);
> ^
> postgres=# select cast('{{1}, {2,3}}' as integer[]);
> int4
> ------------------
> {{1,NULL},{2,3}}
> (1 row)
>
>
> Trying to use an array constructor yields an expected error in both cases.
>
>
> Confirmed on 9.3rc1 and 9.0.13
This is a very interesting report. The behavior you are seeing is based
on this 2004 commit:
commit 0e13d627bebad769498696b5fd0ac821bde5140d
Author: Joe Conway <mail@joeconway.com>
Date: Thu Aug 5 03:30:44 2004 +0000
Require that array literals produce "rectangular" arrays, i.e. all the
subarrays of a given dimension have the same number of elements/subarrays.
Also repair a longstanding undocumented (as far as I can see) ability to
explicitly set array bounds in the array literal syntax. It now can
deal properly with negative array indicies. Modify array_out so that
arrays with non-standard lower bounds (i.e. not 1) are output with
the expicit dimension syntax. This fixes a longstanding issue whereby
arrays with non-default lower bounds had them changed to default
after a dump/reload cycle.
Modify regression tests and docs to suit, and add some minimal
documentation regarding the explicit dimension syntax.
Particularly, this block of code:
if ((nelems_last[nest_level] != 1) &&
(nelems[nest_level] != nelems_last[nest_level]))
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("multidimensional arrays must have "
"array expressions with matching "
"dimensions")));
The nelems_last array is initialized to '1', so when an array comes in
that is one element, no check is made. I doubt this was intended.
What I have done is to change the initalization and test to -1, which
seems to fix the problem.
test=> select cast('{{1}, {2, 3}}' as integer[]);
ERROR: multidimensional arrays must have array expressions with matching dimensions
LINE 1: select cast('{{1}, {2, 3}}' as integer[]);
I was a little worried that this might break existing values stored in
the database, and hence dump/reload, but it seems the arrays are
extended with NULLs so it loads just fine:
CREATE TABLE test(x int[]);
INSERT INTO test SELECT cast('{{1}, {2, 3, 4, 5}}' AS integer[]);
COPY test TO stdout;
{{1,NULL,NULL,NULL},{2,3,4,5}}
Patch attached. The patch controls what strings are accepted as arrays
and will be an incompatibility for 9.4.
Joe, does this sound right?
--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ Everyone has their own god. +
Вложения
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On 01/31/2014 05:11 PM, Bruce Momjian wrote:
> On Tue, Aug 27, 2013 at 08:18:10AM +0000, borz_off@cs.msu.su
> wrote:
>> PostgreSQL documentation states:
>>
>> "Multidimensional arrays must have matching extents for each
>> dimension. A mismatch causes an error..."
>>
>>
>> This is not completely true: postgres=# select cast('{{1,2},
>> {3}}' as integer[]); ERROR: multidimensional arrays must have
>> array expressions with matching dimensions LINE 1: select
>> cast('{{1,2}, {3}}' as integer[]); ^ postgres=# select
>> cast('{{1}, {2,3}}' as integer[]); int4 ------------------
>> {{1,NULL},{2,3}} (1 row)
>>
>>
>> Trying to use an array constructor yields an expected error in
>> both cases.
> Joe, does this sound right?
I believe back when that 2004 commit was made, arrays did not allow
NULL elements at all. So I guess this is an unintended side effect of,
or a latent bug exposed by, that change.
Let me take a closer look...
Joe
- --
Joe Conway
credativ LLC: http://www.credativ.us
Linux, PostgreSQL, and general Open Source
Training, Service, Consulting, & 24x7 Support
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 01/31/2014 05:46 PM, Joe Conway wrote: > On 01/31/2014 05:11 PM, Bruce Momjian wrote: >> Joe, does this sound right? > Let me take a closer look... I had forgotten how convoluted the array code is ;-) Yes, it looks correct to me, although I think I would initialize nelems_last[i] to 0 rather than -1. Joe - -- Joe Conway credativ LLC: http://www.credativ.us Linux, PostgreSQL, and general Open Source Training, Service, Consulting, & 24x7 Support -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJS7IsEAAoJEDfy90M199hlH4YP/1ERkU0XEnZc2FWVANg8NLKk kW3rIa+Q8UUHPVPuhD1GXSXsxBBs5XwJz9rWaTB05iO678eft1FvT2IHciCMKX2m 83FFkXQEEVLr26py+zBnuOVbnmpQ2ubmbr4ZL2fG7KYRzJkPGw4YNmXVWXgyOmOQ gltB3G1q2bNvovIz8OAXkFxkDOjdxfWdbRpoT6pYTGt/wIa5AfWLYxU5v30WZXSC rr0b5rJtn6y4+L2ZsU8HptMVOklbZOkD7+Oee7h5UMB2MazBFMKksaCuBuPGXqJj 2MKtb47xccWWY1mNVF9gdPUSIXtYDDtNjlsBnbP5bWO09UOEuSmoBZd4qG4XKI4b 3dLRskgHZfT5gZVEDaF+vS/7OHI0nGPKhgfT1kNGJZpSpbo5M7lRdcX+lCO4mTkz 7JPZoWmsUqAc8n0eEX/UuwTJL/mzFzowJ0YxaVnqRooIhXwDnQjYCydSuA8mtpTP +qY4IV/4u6yK7c5tM8cOX9ZDkriXvF6yypeIvqKLzHwnu4/6D0RHIusY0fFC+GGY 1jBWHjLYywl59ThauRqWhONiqN1F0roOK0nbdwxe3mw8n+hu/wwmCpyWlPDxUaEa CFXEN5b6uLXDM3Dy0RzvyFn2o0/c9dlleZWp7L8cV+WcU7iULo0LNMli90I+FK9z Cho3QAatYJ6QovloFps/ =XbLY -----END PGP SIGNATURE-----
On Fri, Jan 31, 2014 at 09:49:56PM -0800, Joe Conway wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 01/31/2014 05:46 PM, Joe Conway wrote: > > On 01/31/2014 05:11 PM, Bruce Momjian wrote: > >> Joe, does this sound right? > > > Let me take a closer look... > > I had forgotten how convoluted the array code is ;-) > > Yes, it looks correct to me, although I think I would initialize > nelems_last[i] to 0 rather than -1. Thanks for the review. I went with zero as you suggested. Applied patch attached. -- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. +