ReadRecord wrongly assumes randAccess after 38a957316d.

From 504600f918376f36d8d4d3ccb34e5d004ef8b4df Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Tue, 28 Jan 2020 18:58:05 +0900
Subject: [PATCH] Fix randAccess setting in ReadRecrod

Before the commit 38a957316d, the function assumes random access at
the initial state, on which a valid LSN is given as RecPtr. After the
commit XLogBeginRead initializes reader state by setting ReadRecPtr to
invalid. However ReadRecord was wrongly changed so that a valid
ReadRecPtr is assumed as the initial state. Fix it.
---
 src/backend/access/transam/xlog.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 882d5e8a73..6e09ded597 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -4265,7 +4265,7 @@ ReadRecord(XLogReaderState *xlogreader, int emode,
 	/* Pass through parameters to XLogPageRead */
 	private->fetching_ckpt = fetching_ckpt;
 	private->emode = emode;
-	private->randAccess = (xlogreader->ReadRecPtr != InvalidXLogRecPtr);
+	private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr);
 
 	/* This is the first attempt to read this page. */
 	lastSourceFailed = false;
-- 
2.18.2