[postgres] Really disable dynamic queue size

nyalldawson · nyalldawson · commit ce74d57b2e41 · 2018-06-16T15:36:23.000+10:00
The original commit speed up some layers, but regressed performance for others. It was decided to revert the dynamic queue feature, but it seems this was never actually done. Fixes #16239, #19203
diff --git a/src/providers/postgres/qgspostgresfeatureiterator.cpp b/src/providers/postgres/qgspostgresfeatureiterator.cpp
@@ -28,13 +28,6 @@
 
 QgsPostgresFeatureIterator::QgsPostgresFeatureIterator( QgsPostgresFeatureSource *source, bool ownSource, const QgsFeatureRequest &request )
   : QgsAbstractFeatureIteratorFromSource<QgsPostgresFeatureSource>( source, ownSource, request )
-  , mFeatureQueueSize( 1 )
-  , mFetched( 0 )
-  , mFetchGeometry( false )
-  , mExpressionCompiled( false )
-  , mOrderByCompiled( false )
-  , mLastFetch( false )
-  , mFilterRequiresGeometry( false )
 {
   if ( request.filterType() == QgsFeatureRequest::FilterFids && request.filterFids().isEmpty() )
   {
@@ -260,8 +253,10 @@ bool QgsPostgresFeatureIterator::fetchFeature( QgsFeature &feature )
 
   if ( mFeatureQueue.empty() && !mLastFetch )
   {
+#if 0 //disabled dynamic queue size
     QElapsedTimer timer;
     timer.start();
+#endif
 
     QString fetch = QStringLiteral( "FETCH FORWARD %1 FROM %2" ).arg( mFeatureQueueSize ).arg( mCursorName );
     QgsDebugMsgLevel( QString( "fetching %1 features." ).arg( mFeatureQueueSize ), 4 );
@@ -299,6 +294,7 @@ bool QgsPostgresFeatureIterator::fetchFeature( QgsFeature &feature )
     }
     unlock();
 
+#if 0 //disabled dynamic queue size
     if ( timer.elapsed() > 500 && mFeatureQueueSize > 1 )
     {
       mFeatureQueueSize /= 2;
@@ -307,6 +303,7 @@ bool QgsPostgresFeatureIterator::fetchFeature( QgsFeature &feature )
     {
       mFeatureQueueSize *= 2;
     }
+#endif
   }
 
   if ( mFeatureQueue.empty() )
diff --git a/src/providers/postgres/qgspostgresfeatureiterator.h b/src/providers/postgres/qgspostgresfeatureiterator.h
@@ -102,13 +102,13 @@ class QgsPostgresFeatureIterator : public QgsAbstractFeatureIteratorFromSource<Q
     QQueue<QgsFeature> mFeatureQueue;
 
     //! Maximal size of the feature queue
-    int mFeatureQueueSize;
+    int mFeatureQueueSize = 2000;
 
     //! Number of retrieved features
-    int mFetched;
+    int mFetched = 0;
 
     //! Sets to true, if geometry is in the requested columns
-    bool mFetchGeometry;
+    bool mFetchGeometry = false;
 
     bool mIsTransactionConnection = false;
 
@@ -119,10 +119,10 @@ class QgsPostgresFeatureIterator : public QgsAbstractFeatureIteratorFromSource<Q
     inline void lock();
     inline void unlock();
 
-    bool mExpressionCompiled;
-    bool mOrderByCompiled;
-    bool mLastFetch;
-    bool mFilterRequiresGeometry;
+    bool mExpressionCompiled = false;
+    bool mOrderByCompiled = false;
+    bool mLastFetch = false;
+    bool mFilterRequiresGeometry = false;
 
     QgsCoordinateTransform mTransform;
     QgsRectangle mFilterRect;

Original file line number	Diff line number	Diff line change
`@@ -28,13 +28,6 @@`
`28`	`28`
`29`	`29`	`QgsPostgresFeatureIterator::QgsPostgresFeatureIterator( QgsPostgresFeatureSource *source, bool ownSource, const QgsFeatureRequest &request )`
`30`	`30`	`: QgsAbstractFeatureIteratorFromSource<QgsPostgresFeatureSource>( source, ownSource, request )`
`31`		`- , mFeatureQueueSize( 1 )`
`32`		`- , mFetched( 0 )`
`33`		`- , mFetchGeometry( false )`
`34`		`- , mExpressionCompiled( false )`
`35`		`- , mOrderByCompiled( false )`
`36`		`- , mLastFetch( false )`
`37`		`- , mFilterRequiresGeometry( false )`
`38`	`31`	`{`
`39`	`32`	`if ( request.filterType() == QgsFeatureRequest::FilterFids && request.filterFids().isEmpty() )`
`40`	`33`	`{`
`@@ -260,8 +253,10 @@ bool QgsPostgresFeatureIterator::fetchFeature( QgsFeature &feature )`
`260`	`253`
`261`	`254`	`if ( mFeatureQueue.empty() && !mLastFetch )`
`262`	`255`	`{`
	`256`	`+#if 0 //disabled dynamic queue size`
`263`	`257`	`QElapsedTimer timer;`
`264`	`258`	`timer.start();`
	`259`	`+#endif`
`265`	`260`
`266`	`261`	`QString fetch = QStringLiteral( "FETCH FORWARD %1 FROM %2" ).arg( mFeatureQueueSize ).arg( mCursorName );`
`267`	`262`	`QgsDebugMsgLevel( QString( "fetching %1 features." ).arg( mFeatureQueueSize ), 4 );`
`@@ -299,6 +294,7 @@ bool QgsPostgresFeatureIterator::fetchFeature( QgsFeature &feature )`
`299`	`294`	`}`
`300`	`295`	`unlock();`
`301`	`296`
	`297`	`+#if 0 //disabled dynamic queue size`
`302`	`298`	`if ( timer.elapsed() > 500 && mFeatureQueueSize > 1 )`
`303`	`299`	`{`
`304`	`300`	`mFeatureQueueSize /= 2;`
`@@ -307,6 +303,7 @@ bool QgsPostgresFeatureIterator::fetchFeature( QgsFeature &feature )`
`307`	`303`	`{`
`308`	`304`	`mFeatureQueueSize *= 2;`
`309`	`305`	`}`
	`306`	`+#endif`
`310`	`307`	`}`
`311`	`308`
`312`	`309`	`if ( mFeatureQueue.empty() )`