This commit allows GTM-Standby to connect to GTM anytime. Without this patch,

GTM-Standby must connect to GTM before any clients are connected.   This patch
eliminates this restriction.

In this patch, I used thr_lock RW lock which was not used so far.  When GTM-Standby
connects to GTM, GTM recognizes that this is another GTM (then, standby) and
registers this as another GTM, which will be used later by main thread and
worker thread.

For running worker thread to begin backup to standby, it must connect to it.
Before backup from each running worker threads begin, all the existing transaction
status and sequence status must be backed up.   For this purpose, when GTM-standby
connects to GTM, it issues new message MSG_BEGIN_BACKUP.   When GTM receives this,
GTM locks all the worker thread to make status static.   Then GTM-Standby issues
commands to backup everything.    When backup is done, GTM-Standby issues
MSG_END_BACKUP, whcih release the lock of each worker thread.

When the lock is released, each worker thread checks if there're new GTM-Standby
connected.  If so, each worker thread connects to GTM-Standby and begin backup
of each worker thread.

There're no update in the document.

Affected files are:

	modified:   src/backend/utils/mmgr/mcxt.c
	modified:   src/gtm/client/fe-protocol.c
	modified:   src/gtm/client/gtm_client.c
	modified:   src/gtm/common/gtm_serialize.c
	modified:   src/gtm/common/mcxt.c
	modified:   src/gtm/gtm_ctl/Makefile
	modified:   src/gtm/main/Makefile
	modified:   src/gtm/main/gtm_opt.c
	modified:   src/gtm/main/gtm_standby.c
	modified:   src/gtm/main/gtm_thread.c
	modified:   src/gtm/main/main.c
	modified:   src/gtm/proxy/Makefile
	modified:   src/gtm/proxy/gtm_proxy_opt.c
	modified:   src/gtm/recovery/Makefile
	renamed:    src/gtm/recovery/register.c -> src/gtm/recovery/register_common.c
	new file:   src/gtm/recovery/register_gtm.c
	modified:   src/include/gen_alloc.h
	modified:   src/include/gtm/gtm.h
	modified:   src/include/gtm/gtm_c.h
	modified:   src/include/gtm/gtm_client.h
	modified:   src/include/gtm/gtm_msg.h
	modified:   src/include/gtm/gtm_opt.h
	modified:   src/include/gtm/gtm_standby.h
	modified:   src/include/gtm/gtm_txn.h
	modified:   src/include/gtm/register.h

1 files changed, 7 insertions, 1 deletions

diff --git a/src/backend/utils/mmgr/mcxt.c b/src/backend/utils/mmgr/mcxt.c
index 887241be0a..92473a3b43 100644
--- a/src/backend/utils/mmgr/mcxt.c
+++ b/src/backend/utils/mmgr/mcxt.c
@@ -739,10 +739,16 @@ void *current_memcontext()
 	return((void *)CurrentMemoryContext);
 }
 
+void *allocTopCxt(size_t s)
+{
+	return MemoryContextAlloc(TopMemoryContext, (Size)s);
+}
+
 Gen_Alloc genAlloc_class = {(void *)MemoryContextAlloc,
 							(void *)MemoryContextAllocZero,
 							(void *)repalloc,
 							(void *)pfree,
-							(void *)current_memcontext};
+							(void *)current_memcontext,
+							(void *)allocTopCxt};
 
 #endif