Subject: [PATCH 1/2] Add start timestamp to PGPROC

From: Kyotaro Horiguchi <[email-masked]>
Date: Fri, 1 Feb 2019 09:45:48 +0900

A ProcArray element may be allocated to another session while
investigating. Pid is not fully relialble for cheking that because of
the possibility of reusing. Add start timestamp to resolve the issue.
---
 src/backend/storage/lmgr/proc.c | 2 ++
 src/include/storage/proc.h      | 1 +
 2 files changed, 3 insertions(+)

diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 89c80fb687..a63309a432 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -373,6 +373,8 @@ InitProcess(void)
 	MyProc->fpLocalTransactionId = InvalidLocalTransactionId;
 	MyPgXact->xid = InvalidTransactionId;
 	MyPgXact->xmin = InvalidTransactionId;
+	/* set this before pid to get rid of wrong pair with pid */
+	MyProc->starttimestamp = MyStartTimestamp;
 	MyProc->pid = MyProcPid;
 	/* backendId, databaseId and roleId will be filled in later */
 	MyProc->backendId = InvalidBackendId;
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index d203acbb30..2cebdd2646 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -108,6 +108,7 @@ struct PGPROC
 								 * else InvalidLocalTransactionId */
 	int			pid;			/* Backend's process ID; 0 if prepared xact */
 	int			pgprocno;
+	uint64		starttimestamp;	/* Backend's start timestamp */
 
 	/* These fields are zero while a backend is still starting up: */
 	BackendId	backendId;		/* This backend's backend ID (if assigned) */
-- 
2.16.3

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