I have seen too many "[CRITICAL]:-gpstart failed. (Reason='')
exiting..." errors, and there was nothing in the log. The reason could
be "SSH PATH", "Python modules" or some other issues.

Log the stderr to save debugging efforts.

The 2to3 utility is an officially-supported script to automatically convert
Python 2 code to Python 3.  It's not a complete fix by any means, but it
handles most basic syntax transformations and similar.

This commit is the result of running 2to3 against every Python file in the
gpMgmt directory, so it's quite large and fairly scattershot.  Manual updates
to any code that 2to3 can't handle will come in later commits.

Gphostcache has numerous issues, and has been a pain point for some
time. For this reason, we are removing it.

This commit moves the useful function of gphostcache - the hostname
deduping - to the gparray class, where a list of deduped hostnames is
returned from gpArray.get_hostlist().

There is a FIXME of correctly adding hostname to a newly added or
recovered mirror. The hostname resolution from address was incorrect and
faulty in its logic - an IP address never requires a hostname associated
with it. However, the hostname field in gp_segment_configuration should
be populated somehow - we recommend a "hostname" field addition to any
configuration files that require it. For now, we simple set the
"hostname" to "address" which ultimately delivers the same functionality
as the gphostcache implementation.
Co-authored-by: NTyler Ramer <tramer@vmware.com>
Co-authored-by: NJamie McAtamney <jmcatamney@vmware.com>

base.join_and_indicate_progress() waits for the pool to complete its
work, printing indication dots to stdout once per second. If it takes
less than a second for the pool to complete, we won't print anything
(and we also won't hang for a second waiting for nothing to happen).

The previous implementation required the caller to store a running tally
of how many commands had been added to the pool; that requirement is now
dropped.

Unlike wait_and_printdots(), join_and_indicate_progress() *always*
prints to file. Don't call it if you don't want to print; use
WorkerPool.join() directly.

The pass statement is a no-op intended to be used in empty classes
or other types of stubs. When following other statements in a block
it has no purpose. Remove all such occurrences.
Reviewed-by: NJacob Champion <pchampion@pivotal.io>

Use gpstart '-B' ('--parallel') option value to limit the maximum size
of a thread pool used by gpsegstart to create segments.

gpstart did a cluster-wide check of heap_checksum settings and refused
to start the cluster if this setting was inconsistent. This meant a
round of ssh'ing across the cluster which was causing OOM errors with
large clusters.

This commit moves the heap_checksum validation to gpsegstart.py, and
changes the logic so that only those segments which have the same
heap_checksum setting as master are started.

Author: Jim Doty <jdoty@pivotal.io>
Author: Nadeem Ghani <nghani@pivotal.io>
Author: Shoaib Lari <slari@pivotal.io>

The gprecoverseg tool has been broken after filerep and persistent
tables were removed. This commit cleans it up a little bit and makes
simple incremental mirror recovery work. This does not mean
incremental recovery with pg_rewind is implemented yet though.

Remove the concept of filespaces, revert tablespaces to work the same as
in upstream.

There is some leftovers in management tools. I don't know how to test all
that, and I was afraid of touching things I can't run. Also, we may need
to create replacements for some of those things on top of tablespaces, to
make the management of tablespaces easier, and it might be easier to modify
the existing tools than write them from scratch. (Yeah, you could always
look at the git history, but still.)

Per the discussion on gpdb-dev mailing list, the plan is to cherry-pick
commit 16d8e594 from PostgreSQL 9.2, to make it possible to have a
different path for a tablespace in the primary and its mirror. But that's
not included in this commit yet.

TODO: Make temp_tablespaces work.
TODO: Make pg_dump do something sensible, when dumping from a GPDB 5 cluster
that uses filespaces. Same with pg_upgrade.

Discussion: https://groups.google.com/a/greenplum.org/d/msg/gpdb-dev/sON4lraPEqg/v3lkM587BAAJ

This reverts commit a0fcfc37.

gpstart did a cluster-wide check of heap_checksum settings and refused
to start the cluster if this setting was inconsistent. This meant a
round of ssh'ing across the cluster which was causing OOM errors with
large clusters.

This commit moves the heap_checksum validation to gpsegstart.py, and
changes the logic so that only those segments which have the same
heap_checksum setting as master are started.

Author: Nadeem Ghani <nghani@pivotal.io>
Author: Shoaib Lari <slari@pivotal.io>

The locale information is not used for anything, so no need to collect and
pass it around.

This will no longer spill logfiles from the demo cluster into
the users ~/gpAdminLogs directory. Also it makes it easier to
identify which logfile was created by the last regression test run.

Closes #689
Closes #523