When constructing the connectionstring for connecting to the QEs,
ensure we don't overflow the assigned buffer.
Reviewed-by: NGang Xiong <gxiong@pivotal.io>

Code had these two variables (GUCs), serving same purpose. GpIdentity.segindex
is set to content-id, based on command line argument at start-up and inherited
by all processes from postmaster. Whereas Gp_segment, was session level guc only
set for backends, by dispatching the same from QD. So. essentially Gp_segment
was not available and had incorrect value in auxiliary processes.

Hence replaced all usages with GpIdentity.segindex. As a side effect log files
now have correct value reported for segment number (content-id) in each and
every line of file, irrespective of which process generated the log message.

Discussion:
https://groups.google.com/a/greenplum.org/forum/#!msg/gpdb-dev/Yr8-LZIiNfA/ob4KLgmkAQAJ

This ftsEnabled variable is no longer necessary because FTS is always
enabled now. Back in 4.3.x and 5.x, this variable was a representation
of whether or not the cluster had filerep mirrors.

Author: Xin Zhang <xzhang@pivotal.io>
Author: Jimmy Yih <jyih@pivotal.io>

Signed-off-by: NAdam Lee <ali@pivotal.io>

This bumps the copyright years to the appropriate years after not
having been updated for some time.  Also reformats existing code
headers to match the upstream style to ensure consistency.

It was getting in the way of backporting commit 9b1b9446f5 from PostgreSQL,
which added an '#include "storage/lock.h"' to resowner.h, forming a cycle.

The include was only needed for the decalaration of awaitedOwner global
variable. Replace "ResourceOwner" with the equivalent "struct
ResourceOwnerData *" to avoid it.

This revealed a bunch of other files that were relying on resowner.h
being indirectly included through lock.h. Include resowner.h directly
in those files.

The ResPortalIncrement.owner field was not used for anything, so instead
of including resowner.h in that file, just remove the field that needed
it.

The whole cdb directory was shipped to end users and all header files
that cdb*.h included are also need to be shipped to make checkinc.py
pass. However, exposing gp_libpq_fe/*.h will confuse customer because
they are almost the same as libpq/*, as Heikki's suggestion, we should
keep gp_libpq_fe/* unchanged. So to make system work, we include
gp-libpg-fe.h and gp-libpq-int.h directly in c files that need them

StringInfo is more appropriate in backend code. (Unless the buffer needs to
be used in a thread.)

In the passing, rename the 'conn' static variable in cdbfilerepconnclient.c.
It seemed overly generic.

Implement resgroup memory limit.

In a resgroup we divide the memory into several slots, the number
depends on the concurrency setting in the resgroup. Each slot has a
reserved quota of memory, all the slots also share some shared memory
which can be acquired preemptively.

Some GUCs and resgroup options are defined to adjust the exact allocation
policy:

resgroup options:
- memory_shared_quota
- memory_spill_ratio

GUCs:
- gp_resource_group_memory_limit
Signed-off-by: NNing Yu <nyu@pivotal.io>

If QD receives a SIGINT and calls CHECK_FOR_INTERRUPTS after finishing Gang creation, but before recording this Gang in global variables like primaryWriterGang, this Gang would not be destroyed, hence next time QD wants to create a new writer Gang, it would find existing writer Gang on segments, and report snapshot collision error.

This commit reverted the recreation logic for primary writer gang involved in commit e28c84b2 which make some
test cases got unexpected answer files, this commit also improved getAvailableGang() so it can go through the
whole freelist of reader gangs until it found a healthy gang.

On the first iteration we know the structs are empty, but when coming
into create_gang_retry we must ensure that they have been freed. Move
to Assertions rather than setting NULL since that's already performed
before returning to the retry label.

Initially per a false positive gripe in Coverity.

Signed-off-by: NKenan Yao <kyao@pivotal.io>

1. Remove retry mechanism for reader gang and non "in recovery mode" error, gp_segment_connect_timeout is default
set to 10 mins, so it should be long enough to say we temporary lost the segments.

2. Fix "in recovery mode" retry mechanism, original codes can not recognize a in-recovery-mode error.

3. Add failure details. "failed to acquire resources on one or more segments" hide too many details.