From 72e373cd4eb3e5451be4dcd975b1e4b87cec9167 Mon Sep 17 00:00:00 2001
From: Konstantin Knizhnik <knizhnik@garret.ru>
Date: Mon, 24 May 2021 12:29:14 +0300
Subject: [PATCH] Fix maintaining of next multixact

---
 pageserver/src/basebackup.rs |  1 -
 pageserver/src/waldecoder.rs | 16 ++++++++--------
 vendor/postgres              |  2 +-
 3 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/pageserver/src/basebackup.rs b/pageserver/src/basebackup.rs
index d0067f3890..36cb0e2ab5 100644
--- a/pageserver/src/basebackup.rs
+++ b/pageserver/src/basebackup.rs
@@ -158,7 +158,6 @@ fn add_pgcontrol_file(
             let mut checkpoint = postgres_ffi::decode_checkpoint(checkpoint_bytes)?;
 
             checkpoint.redo = lsn.0;
-            checkpoint.nextXid.value += 1;
             // TODO: When we restart master there are no active transaction and oldestXid is
             // equal to nextXid if there are no prepared transactions.
             // Let's ignore them for a while...
diff --git a/pageserver/src/waldecoder.rs b/pageserver/src/waldecoder.rs
index b94a471a66..8edfe0bcc7 100644
--- a/pageserver/src/waldecoder.rs
+++ b/pageserver/src/waldecoder.rs
@@ -574,10 +574,10 @@ pub fn decode_wal_record(checkpoint: &mut CheckPoint, record: Bytes) -> DecodedW
         xlogrec.xl_rmid,
         xlogrec.xl_info
     );
-    if xlogrec.xl_xid > checkpoint.nextXid.value as u32 {
+    if xlogrec.xl_xid >= checkpoint.nextXid.value as u32 {
         // TODO: handle XID wraparound
         checkpoint.nextXid = FullTransactionId {
-            value: (checkpoint.nextXid.value & 0xFFFFFFFF00000000) | xlogrec.xl_xid as u64,
+            value: (checkpoint.nextXid.value & 0xFFFFFFFF00000000) | (xlogrec.xl_xid+1) as u64,
         };
     }
     let remaining = xlogrec.xl_tot_len - SizeOfXLogRecord;
@@ -1080,18 +1080,18 @@ pub fn decode_wal_record(checkpoint: &mut CheckPoint, record: Bytes) -> DecodedW
                 blk.blkno = blkno;
                 blocks.push(blk);
             }
-            if xlrec.mid > checkpoint.nextMulti {
-                checkpoint.nextMulti = xlrec.mid;
+            if xlrec.mid >= checkpoint.nextMulti {
+                checkpoint.nextMulti = xlrec.mid+1;
             }
-            if xlrec.moff > checkpoint.nextMultiOffset {
-                checkpoint.nextMultiOffset = xlrec.moff;
+            if xlrec.moff+xlrec.nmembers > checkpoint.nextMultiOffset {
+                checkpoint.nextMultiOffset = xlrec.moff+xlrec.nmembers;
             }
             let max_xid = xlrec
                 .members
                 .iter()
                 .fold(checkpoint.nextXid.value as u32, |acc, mbr| {
-                    if mbr.xid > acc {
-                        mbr.xid
+                    if mbr.xid >= acc {
+                        mbr.xid+1
                     } else {
                         acc
                     }
diff --git a/vendor/postgres b/vendor/postgres
index 1ac4f5b6b1..fd9de093b0 160000
--- a/vendor/postgres
+++ b/vendor/postgres
@@ -1 +1 @@
-Subproject commit 1ac4f5b6b1fe7a4e4cc5b0c5e209999fdc2310ba
+Subproject commit fd9de093b0e115459c8816895d2ac37da2599aca