From c1fe0cb8e9aeb39c9964dda99f8ec9201e095fc2 Mon Sep 17 00:00:00 2001
From: Volodymyr Mostepaniuk <mostepaniukvm@gmail.com>
Date: Tue, 9 Feb 2021 19:29:55 +0200
Subject: [PATCH 1/3] Put sequence id from last changes request.

---
 src/Replication.php | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/src/Replication.php b/src/Replication.php
index d2a7272..2a739c6 100644
--- a/src/Replication.php
+++ b/src/Replication.php
@@ -192,18 +192,17 @@ public function getReplicationLog()
      */
     public function putReplicationLog(array $response) {
         $sessionId = \md5((\microtime(true) * 1000000));
-        $sourceInfo = $this->source->getDatabaseInfo($this->source->getDatabase());
         $data = [
             '_id' => '_local/' . $this->task->getRepId(),
             'history' => [
-                'recorded_seq' => $sourceInfo['update_seq'],
+                'recorded_seq' => $response['end_last_seq'],
                 'session_id' => $sessionId,
                 'start_time' => $this->startTime->format('D, d M Y H:i:s e'),
                 'end_time' => $this->endTime->format('D, d M Y H:i:s e'),
             ],
             'replication_id_version' => 3,
             'session_id' => $sessionId,
-            'source_last_seq' => $sourceInfo['update_seq']
+            'source_last_seq' => $response['end_last_seq'],
         ];
 
         if (isset($response['doc_write_failures'])) {
@@ -473,9 +472,7 @@ public function locateChangedDocumentsAndReplicate($printStatus, $getFinalReport
             if (isset($changes['results'][0]['seq'])) {
                 $finalResponse['start_last_seq'] = $changes['results'][0]['seq'];
             }
-            if (isset($changes['last_seq'])) {
-                $finalResponse['end_last_seq'] = $changes['last_seq'];
-            }
+            $finalResponse['end_last_seq'] = $since;
             foreach ($response['multipartResponse'] as $docID => $res) {
                 // Add the response of posting each revision of the
                 // doc that had attachments.

From 9d9f0fafffe4a5ec2e345a7f33ff0669107d0ee4 Mon Sep 17 00:00:00 2001
From: Volodymyr Mostepaniuk <mostepaniukvm@gmail.com>
Date: Tue, 16 Feb 2021 15:54:12 +0200
Subject: [PATCH 2/3] Return previous code as fallback.

---
 src/Replication.php | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/Replication.php b/src/Replication.php
index 2a739c6..c26fef0 100644
--- a/src/Replication.php
+++ b/src/Replication.php
@@ -192,17 +192,26 @@ public function getReplicationLog()
      */
     public function putReplicationLog(array $response) {
         $sessionId = \md5((\microtime(true) * 1000000));
+        if (!empty($response['end_last_seq'])) {
+          $last_sequence_id = $response['end_last_seq'];
+        }
+        else {
+          // For some reason end_last_seq was 0 on production. Use previous
+          // code as fallback value.
+          $sourceInfo = $this->source->getDatabaseInfo($this->source->getDatabase());
+          $last_sequence_id = $sourceInfo['update_seq'];
+        }
         $data = [
             '_id' => '_local/' . $this->task->getRepId(),
             'history' => [
-                'recorded_seq' => $response['end_last_seq'],
+                'recorded_seq' => $last_sequence_id,
                 'session_id' => $sessionId,
                 'start_time' => $this->startTime->format('D, d M Y H:i:s e'),
                 'end_time' => $this->endTime->format('D, d M Y H:i:s e'),
             ],
             'replication_id_version' => 3,
             'session_id' => $sessionId,
-            'source_last_seq' => $response['end_last_seq'],
+            'source_last_seq' => $last_sequence_id,
         ];
 
         if (isset($response['doc_write_failures'])) {

From 3d4b66fc909010655938ab76fbe99096e7018093 Mon Sep 17 00:00:00 2001
From: Volodymyr Mostepaniuk <mostepaniukvm@gmail.com>
Date: Tue, 16 Feb 2021 16:56:56 +0200
Subject: [PATCH 3/3] Subtract 5 minutes to prevent race condition issue.

---
 src/Replication.php | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/Replication.php b/src/Replication.php
index c26fef0..647ed4f 100644
--- a/src/Replication.php
+++ b/src/Replication.php
@@ -196,10 +196,11 @@ public function putReplicationLog(array $response) {
           $last_sequence_id = $response['end_last_seq'];
         }
         else {
-          // For some reason end_last_seq was 0 on production. Use previous
-          // code as fallback value.
+          // For some reason end_last_seq was 0 on production for some cases.
+          // Use previous code as fallback value just subtract 5 minutes to
+          // prevent race condition issue.
           $sourceInfo = $this->source->getDatabaseInfo($this->source->getDatabase());
-          $last_sequence_id = $sourceInfo['update_seq'];
+          $last_sequence_id = $sourceInfo['update_seq'] - 5 * 60 * 1000000;
         }
         $data = [
             '_id' => '_local/' . $this->task->getRepId(),