BUG #6676: checkpointer does not work by SIGINT.

The following bug has been logged on the website:

Bug reference:      6676
Logged by:          Tomonari Katsumata
Email address:      katsumata.tomonari@po.ntts.co.jp
PostgreSQL version: Unsupported/Unknown
Operating system:   RHEL 5.7 x86_64
Description:=20=20=20=20=20=20=20=20

Hi,

Now I'm testing the behavior of checkpointer,
and I found a difference with PostgreSQL9.1 behavior.

When I send SIGINT signal to writer process on PostgreSQL9.1,=20
writer process starts checkpoint.
But, when I send SIGINT signal to checkpointer on PostgreSQL9.2beta2,=20
checkpointer doesn't start checkpoint.


<PostgreSQL 9.1.3>
change the config file(postgresql.conf) to log information about
checkpoint.
log_checkpoints =3D on
logging_collector =3D on

$ psql postgres -c "create table tbl(i int)"
CREATE TABLE

$ psql postgres -c "insert into tbl values(1);"
INSERT 0 1

$ ps faxww | grep postgres | grep "writer process"
19706 ?        Ss     0:00  \_ postgres: writer process
19707 ?        Ss     0:00  \_ postgres: wal writer process

$ kill -2 19706

<log messages>
LOG:  checkpoint starting:
LOG:  checkpoint complete: wrote 1 buffers (0.0%); 0 transaction log file(s)
added, 0 removed, 0 recycled; write=3D0.000 s, sync=3D0.001 s, total=3D0.00=
4 s;
sync files=3D1, longest=3D0.001 s, average=3D0.001 s

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
<PostgreSQL 9.2beta2>
change the config file(postgresql.conf) to log information about
checkpoint.
log_checkpoints =3D on
logging_collector =3D on

$ psql postgres -c "create table tbl(i int);"
CREATE TABLE

$ psql postgres -c "insert into tbl values(1);"
INSERT 0 1
$ ps faxww | grep checkpointer
11526 pts/3    S+     0:00  |           \_ grep checkpointer
11482 ?        Ss     0:00  \_ postgres: checkpointer process=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20
=20=20=20=20=20=20

$ kill -2 11482

<no log messages>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

I know "latch" is introduced on PostgreSQL9.2,=20
but I'm not sure this is a bug or not.
Is this a desirable behavior of "latch" ?