> On Apr 2, 2016, at 3:14 AM, Michael Paquier <michael.paqu...@gmail.com> wrote:
>
> On Fri, Apr 1, 2016 at 10:53 PM, Stas Kelvich <s.kelv...@postgrespro.ru>
> wrote:
>> I wrote:
>>> While testing the patch, I found a bug in the recovery conflict code
>>> path. You can do the following to reproduce it:
>>> 1) Start a master with a standby
>>> 2) prepare a transaction on master
>>> 3) Stop immediate on standby to force replay
>>> 4) commit prepare transaction on master
>>> 5) When starting the standby, it remains stuck here:
>>
>> Hm, I wasn’t able to reproduce that. Do you mean following scenario or am I
>> missing something?
>>
>> (async replication)
>>
>> $node_master->psql('postgres', "
>> begin;
>> insert into t values (1);
>> prepare transaction 'x';
>> ");
>> $node_slave->teardown_node;
>> $node_master->psql('postgres',"commit prepared 'x'");
>> $node_slave->start;
>> $node_slave->psql('postgres',"select count(*) from pg_prepared_xacts",
>> stdout => \$psql_out);
>> is($psql_out, '0', "Commit prepared on master while slave is down.");
>
> Actually, not exactly, the transaction prepared on master created a
> table. Sorry for the lack of precisions in my review.
Sorry for delay.
Actually I can’t reproduce that again, tried with following tx:
begin;
insert into t values(0);
create table t1(id int);
insert into t1 values(1);
create table t2(id int);
insert into t2 values(2);
savepoint s1;
drop table t1;
select * from t for update;
select * from t2 for share;
prepare transaction 'x’;
use strict;
use warnings;
use PostgresNode;
use TestLib;
use Test::More tests => 2;
# Setup master node
my $node_master = get_new_node("master");
$node_master->init(allows_streaming => 1);
$node_master->append_conf('postgresql.conf', qq(
max_prepared_transactions = 10
));
$node_master->start;
$node_master->backup('master_backup');
$node_master->psql('postgres', "create table t(id int)");
# Setup slave node
my $node_slave = get_new_node('slave');
$node_slave->init_from_backup($node_master, 'master_backup', has_streaming => 1);
$node_slave->start;
my $psql_out = '';
my $psql_rc = '';
$node_master->psql('postgres', "
begin;
insert into t values(0);
create table t1(id int);
insert into t1 values(1);
create table t2(id int);
insert into t2 values(2);
savepoint s1;
drop table t1;
select * from t for update;
select * from t2 for share;
prepare transaction 'x';
");
sleep 2; # wait for changes to arrive on slave
$node_slave->teardown_node;
$node_master->psql('postgres',"commit prepared 'x'");
$node_slave->start;
$node_slave->psql('postgres',"select count(*) from pg_prepared_xacts", stdout => \$psql_out);
is($psql_out, '0', "Commit prepared on master while slave is down.");
$node_slave->psql('postgres',"select sum(id) from t2", stdout => \$psql_out);
is($psql_out, '2', "Check that tx changes are visible.");
--
Stas Kelvich
Postgres Professional: http://www.postgrespro.com
Russian Postgres Company
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