wsrep_check_opts doesn't check for default values

[Raghavendra D Prabhu]

As discussed in https://bugs.launchpad.net/percona-xtradb-cluster/+bug/1242867/comments/3 (and comment before that), wsrep_check_opts only checks if the opt/value has been specified in cnf or command line explicitly.

For example, binlog_format is STATEMENT by default. So, if it is not set in my.cnf, it doesn't fail, only when it is explicitly set it fails.

============
sudo /pxc/bin/mysqld --defaults-file=/pxc/etc/my.cnf.local --basedir=/pxc --user=mysql --wsrep-cluster-address="gcomm://?pc.ignore_sb=true" --wsrep-start-position='5805bbc4-3038-11e3-937d-aa946afe7370:100' --binlog_format=MIXED
131022 19:29:24 [Warning] WSREP: wsrep_sst_receive_address is set to '127.0.0.1:4001' which makes it impossible for another host to reach this one. Please set it to the address which this node can be connected at by other cluster members.
131022 19:29:24 [ERROR] WSREP: Only binlog_format = 'ROW' is currently supported. Configured value: 'MIXED'. Please adjust your configuration.
131022 19:29:24 [ERROR] Aborting
======================

So, it needs to be either fixed to check for default values or the default have to be adjusted appropriately. Latter is simpler but may break compatibility with mysql.

[Raghavendra D Prabhu (raghavendra-prabhu)]

Also, even though it may be fine to set defaults, it may be problematic when that pxc node is used as an async slave or for any other purpose.

Specifically, following options:

"wsrep_slave_threads", "1"
"bind_address", "0.0.0.0"
"wsrep_sst_method", "rsync"
"wsrep_sst_receive_address","AUTO"
"binlog_format", "ROW"
"wsrep_provider", "none"
"query_cache_type", "0"
"query_cache_size", "0"
"locked_in_memory", "0"
"wsrep_cluster_address", "0"
"locks_unsafe_for_binlog", "0"
"autoinc_lock_mode", "1"

Out of the above, the options with bad defaults are:

"binlog_format", (STATEMENT)
"query_cache_type", (1)
"autoinc_lock_mode" (1)

==============================

This should also avoid people crashing their nodes with bad
defaults and reporting bugs on that :) (seen many bugs with STMT
binlog_format).

[Raghavendra D Prabhu (raghavendra-prabhu)]

Since the defaults are for the above three variables are values which are not just bad but also incorrect (for galera), adjusting defaults makes sense here.

[Raghavendra D Prabhu (raghavendra-prabhu)]

Since, following are required for proper functioning, changed as following:

"binlog_format", (STATEMENT) => ROW
"autoinc_lock_mode" (1) => 2

[Raghavendra D Prabhu (raghavendra-prabhu)]

The " "autoinc_lock_mode" (1) => 2" has been added but wsrep logic prevents it when parallel threads are there. Hence, this change has not been noted in documentation (so you still need to provide in my.cnf). This will be dealt with in a separate issue.

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PXC-1486