Possible index issue on 9.5 slave

Hi

I've just run into an index issue on 9.5 HEAD on a slave (master and slave
both compiled from 66802246e22d51858cd543877fcfddf24e6812f2); details
below (I have only found one index on the slave where the issue occurs so far).
The setup is admittedly slightly unusual; master is OS X 10.7.5, slave is
CentOS on a Virtualbox guest VM on the same system. The issue only occurs
with this combination of master and slave; I haven't been able to reproduce
it with master and slave running natively on OS X, or with a Linux guest VM
on a Linux machine. I have reproduced it several times on the OS X/Linux guest VM
combination.

I can't dig any further into this at the moment but can happily provide further
details etc.

Master
======

$ uname -a
Darwin nara.local 11.4.2 Darwin Kernel Version 11.4.2: Thu Aug 23 16:25:48 PDT 2012; root:xnu-1699.32.7~1/RELEASE_X86_64 x86_64

tgg_current=> SELECT version();
version
----------------------------------------------------------------------------------------------------------
PostgreSQL 9.5devel on x86_64-apple-darwin11.4.2, compiled by gcc (MacPorts gcc48 4.8.2_2) 4.8.2, 64-bit
(1 row)

tgg_current=> select user_id, login from tgg_user where login ='admin';
user_id | login
---------+-------
1 | admin
(1 row)

Slave
=====

$ uname -a
Linux localhost.localdomain 2.6.32-358.el6.x86_64 #1 SMP Fri Feb 22 00:31:26 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

tgg_current=> select version();
version
-----------------------------------------------------------------------------------------------------------------
PostgreSQL 9.5devel on x86_64-unknown-linux-gnu, compiled by gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-3), 64-bit
(1 row)

tgg_current=> select user_id,login from tgg_user where login ='admin';
user_id | login
---------+-------
(0 rows)

tgg_current=> explain select user_id,login from tgg_user where login ='admin';
QUERY PLAN
------------------------------------------------------------------------------------
Index Scan using tgg_user_login_key on tgg_user (cost=0.28..8.30 rows=1 width=15)
Index Cond: ((login)::text = 'admin'::text)
Planning time: 0.105 ms
(3 rows)

tgg_current=> set enable_bitmapscan=off;
SET
tgg_current=> set enable_indexscan =off;
SET
tgg_current=> select user_id,login from tgg_user where login ='admin';
user_id | login
---------+-------
1 | admin
(1 row)

tgg_current=> \d tgg_user_login_key
Index "epp.tgg_user_login_key"
Column | Type | Definition
--------+-----------------------+------------
login | character varying(32) | login
unique, btree, for table "epp.tgg_user"

Regards

Ian Barwick

--
Ian Barwick http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services