multi-install PostgresNode fails with older postgres versions

Andrew,

While developing some cross version tests, I noticed that PostgresNode::init fails for postgres versions older than 9.3, like so:

# Checking port 52814
# Found port 52814
Name: 9.2.24
Data directory: /Users/mark.dilger/hydra/postgresnode.review/src/test/modules/test_cross_version/tmp_check/t_001_verify_paths_9.2.24_data/pgdata
Backup directory: /Users/mark.dilger/hydra/postgresnode.review/src/test/modules/test_cross_version/tmp_check/t_001_verify_paths_9.2.24_data/backup
Archive directory: /Users/mark.dilger/hydra/postgresnode.review/src/test/modules/test_cross_version/tmp_check/t_001_verify_paths_9.2.24_data/archives
Connection string: port=52814 host=/var/folders/6n/3f4vwbnn7fz5qk0xqhgbjrkw0000gp/T/L_A2w1x7qb
Log file: /Users/mark.dilger/hydra/postgresnode.review/src/test/modules/test_cross_version/tmp_check/log/001_verify_paths_9.2.24.log
# Running: initdb -D /Users/mark.dilger/hydra/postgresnode.review/src/test/modules/test_cross_version/tmp_check/t_001_verify_paths_9.2.24_data/pgdata -A trust -N
initdb: invalid option -- N
Try "initdb --help" for more information.
Bail out!  system initdb failed

The problem is clear enough; -N/--nosync was added in 9.3, and PostgresNode::init is passing -N to initdb unconditionally. I wonder if during PostgresNode::new a call should be made to pg_config and the version information grep'd out so that version specific options to various functions (init, backup, etc) could hinge on the version of postgres being used?

You could also just remove the -N option, but that would slow down all tests for everybody, so I'm not keen to do that.  Or you could remove -N in cases where $node->{_install_path} is defined, which would be far more acceptable.  I'm leaning towards using the output of pg_config, though, since this problem is likely to come up again with other options/commands.

Thoughts?

—
Mark Dilger
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company