Fix comment that Vadim found confusing.

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 5eb5896034675298ebcbe27c099d5df474a2549d..4ef37f00fa768e49703232f2c0fb10a1fc28c599 100644 (file)
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -2467,6 +2467,7 @@ StartupXLOG(void)
                        Insert->currpage->xlp_sui = ThisStartUpID;
                else
                        Insert->currpage->xlp_sui = ThisStartUpID + 1;
+               /* rest of buffer was zeroed in XLOGShmemInit */
        }
        else
        {
@@ -2475,10 +2476,8 @@ StartupXLOG(void)
                        ((EndOfLog.xrecoff - 1) / BLCKSZ + 1) * BLCKSZ;
                /*
                 * Tricky point here: readBuf contains the *last* block that the
-                * LastRec record spans, not the one it starts in, which is what we
-                * want.
-                *
-                * XXX - why would we want block LastRec starts in?
+                * LastRec record spans, not the one it starts in.  The last block
+                * is indeed the one we want to use.
                 */
                Assert(readOff == (XLogCtl->xlblocks[0].xrecoff - BLCKSZ) % XLogSegSize);
                memcpy((char *) Insert->currpage, readBuf, BLCKSZ);