Support defer loading of dataTables data

CHANGELOG.md

@@ -37,6 +37,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 #### Changed
 
+- Source query results table is no longer populated by default, a query must be submitted first [#638](https://github.com/askap-vast/vast-pipeline/pull/638).
 - Bumped major versions of astropy (5.0) and pyarrow (7.0) [#641](https://github.com/askap-vast/vast-pipeline/pull/641).
 - Addressed future pandas append deprecation, migrated all uses to pd.concat [#643](https://github.com/askap-vast/vast-pipeline/pull/643).
 - Bumped all documentation dependancies to latest versions (incl. mkdocs-material minimum 8.2.4) [#627](https://github.com/askap-vast/vast-pipeline/pull/627).
@@ -90,6 +91,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 #### List of PRs
 
+- [#638](https://github.com/askap-vast/vast-pipeline/pull/638): feat: Support defer loading of dataTables data.
 - [#641](https://github.com/askap-vast/vast-pipeline/pull/641): dep: Drop Python 3.7 and dependency refresh.
 - [#643](https://github.com/askap-vast/vast-pipeline/pull/643): fix: Addressed pandas DataFrame.append deprecation.
 - [#642](https://github.com/askap-vast/vast-pipeline/pull/642): fix: Fix empty groups in parallel association.

static/js/datatables-pipeline.js

@@ -154,6 +154,14 @@ $(document).ready(function() {
         dom : dom,
         buttons: DEFAULT_DATATABLE_BUTTONS
       };
+      // apply deferLoading config, if supplied
+      if (dataConf.hasOwnProperty('deferLoading')) {
+        dataTableConf.deferLoading = dataConf.deferLoading;
+        // change the message printed in the empty table if deferLoading active
+        dataTableConf.initComplete = function(settings, json) {
+          $("td.dataTables_empty").text("Submit a query to view results");
+        }
+      }
     } else {
       // expect that there is a 'data' attribute with the data
       // data are in this format

vast_pipeline/views.py

@@ -1504,6 +1504,7 @@ def SourceQuery(request):
                     'New High Sigma'
                 ],
                 'search': False,
+                'deferLoading': 0,  # don't fetch results until a query is made
             }
         }
     )