From 5e91ed2bb1123b7bc7a96ee783d50b8b8b2f716b Mon Sep 17 00:00:00 2001
From: Nagesh Dhope <nagesh.dhope@enterprisedb.com>
Date: Wed, 22 Apr 2020 17:54:32 +0530
Subject: [PATCH] Fixed slider jump issue by making an API call to fetch the
 next batch of rows only after a user stops scrolling down. Fixes #3269

---
 web/pgadmin/tools/sqleditor/__init__.py       |  5 +++--
 .../tools/sqleditor/static/js/sqleditor.js    | 19 ++++++++++++-------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/web/pgadmin/tools/sqleditor/__init__.py b/web/pgadmin/tools/sqleditor/__init__.py
index 35e1bf3dc..88bc3c959 100644
--- a/web/pgadmin/tools/sqleditor/__init__.py
+++ b/web/pgadmin/tools/sqleditor/__init__.py
@@ -564,8 +564,6 @@ def fetch(trans_id, fetch_all=None, fetch_till=None):
         else:
             status = 'Success'
             res_len = len(result)
-            if fetch_row_cnt != -1 and res_len == ON_DEMAND_RECORD_COUNT:
-                has_more_rows = True
 
             if res_len:
                 rows_fetched_from = trans_obj.get_fetched_row_cnt()
@@ -574,6 +572,9 @@ def fetch(trans_id, fetch_all=None, fetch_till=None):
                 rows_fetched_to = trans_obj.get_fetched_row_cnt()
                 session_obj['command_obj'] = pickle.dumps(trans_obj, -1)
                 update_session_grid_transaction(trans_id, session_obj)
+
+            if fetch_row_cnt != -1 and rows_fetched_to < conn.rows_affected():
+                has_more_rows = True
     else:
         status = 'NotConnected'
         result = error_msg
diff --git a/web/pgadmin/tools/sqleditor/static/js/sqleditor.js b/web/pgadmin/tools/sqleditor/static/js/sqleditor.js
index d41244ce6..e0a6c99b4 100644
--- a/web/pgadmin/tools/sqleditor/static/js/sqleditor.js
+++ b/web/pgadmin/tools/sqleditor/static/js/sqleditor.js
@@ -1213,12 +1213,17 @@ define('tools.querytool', [
       }.bind(editor_data));
 
       grid.onScroll.subscribe((e, args) => {
-        if (self.handler.has_more_rows && !self.handler.fetching_rows && args.grid.getViewport().bottom > self.handler.rows_fetched_to + self.handler.rows_fetch_batch_count) {
-          // fast scrolling
-          let fetch_till = ((args.grid.getViewport().bottom % self.handler.rows_fetch_batch_count) + 1) * self.handler.rows_fetch_batch_count;
-          self.fetch_next(null, null, fetch_till);
-        } else if (self.handler.has_more_rows && !self.handler.fetching_rows && args.grid.getViewport().bottom + 100 > self.handler.rows_fetched_to) {
-          // gentle scroll
+        clearTimeout($.data(this, 'scrollTimer'));
+        $.data(this, 'scrollTimer', setTimeout(function () {
+          if (self.handler.has_more_rows && !self.handler.fetching_rows && args.grid.getViewport().bottom > self.handler.rows_fetched_to + self.handler.rows_fetch_batch_count) {
+            // fast scrolling using slider
+            let fetch_till = (parseInt(args.grid.getViewport().bottom / self.handler.rows_fetch_batch_count) + 1) * self.handler.rows_fetch_batch_count;
+            self.fetch_next(null, null, fetch_till);
+          }
+        }, 250));
+        // If its gentle scroll, when last 10% of rows are left to scroll then fetch next batch of rows
+        if (self.handler.has_more_rows && !self.handler.fetching_rows && args.grid.getViewport().bottom + (self.handler.rows_fetch_batch_count * 0.1) > self.handler.rows_fetched_to) {
+          // gentle scroll using mouse
           setTimeout(self.fetch_next.bind(self));
         }
       });
@@ -1310,7 +1315,7 @@ define('tools.querytool', [
           $('#btn-download').prop('disabled', false);
           self.handler.trigger('pgadmin-sqleditor:loading-icon:hide');
           self.handler.rows_fetched_to = res.data.rows_fetched_to;
-          self.update_grid_data(res.data.result);
+          setTimeout(() => self.update_grid_data(res.data.result), 100);
           self.handler.fetching_rows = false;
           if (typeof cb == 'function') {
             cb();