Make number of rows to prefetch when doing lazy population configuarable

Add a new option to the settings dialog to allow changing the number of
rows to get at a time.

src/PreferencesDialog.cpp

@@ -43,6 +43,7 @@ void PreferencesDialog::loadSettings()
     ui->encodingComboBox->setCurrentIndex(ui->encodingComboBox->findText(getSettingsValue("db", "defaultencoding").toString(), Qt::MatchFixedString));
     ui->locationEdit->setText(getSettingsValue("db", "defaultlocation").toString());
     ui->foreignKeysCheckBox->setChecked(getSettingsValue("db", "foreignkeys").toBool());
+    ui->spinPrefetchSize->setValue(getSettingsValue("db", "prefetchsize").toInt());
 
     for(int i=0;i<ui->treeSyntaxHighlighting->topLevelItemCount();i++)
     {
@@ -63,6 +64,7 @@ void PreferencesDialog::saveSettings()
     setSettingsValue("db", "defaultencoding", ui->encodingComboBox->currentText());
     setSettingsValue("db", "defaultlocation", ui->locationEdit->text());
     setSettingsValue("db", "foreignkeys", ui->foreignKeysCheckBox->isChecked());
+    setSettingsValue("db", "prefetchsize", ui->spinPrefetchSize->value());
 
     for(int i=0;i<ui->treeSyntaxHighlighting->topLevelItemCount();i++)
     {
@@ -120,6 +122,10 @@ QVariant PreferencesDialog::getSettingsDefaultValue(const QString& group, const
     if(group == "db" && name == "foreignkeys")
         return true;
 
+    // db/prefetchsize?
+    if(group == "db" && name == "prefetchsize")
+        return 50000;
+
     // MainWindow/geometry?
     if(group == "MainWindow" && name == "geometry")
         return "";

src/PreferencesDialog.ui

@@ -102,6 +102,26 @@
          </item>
         </layout>
        </item>
+       <item row="3" column="0">
+        <widget class="QLabel" name="label_2">
+         <property name="text">
+          <string>&amp;Prefetch block size</string>
+         </property>
+         <property name="buddy">
+          <cstring>spinPrefetchSize</cstring>
+         </property>
+        </widget>
+       </item>
+       <item row="3" column="1">
+        <widget class="QSpinBox" name="spinPrefetchSize">
+         <property name="minimum">
+          <number>255</number>
+         </property>
+         <property name="maximum">
+          <number>1000000</number>
+         </property>
+        </widget>
+       </item>
       </layout>
      </widget>
      <widget class="QWidget" name="tab_2">
@@ -271,6 +291,7 @@
   <tabstop>foreignKeysCheckBox</tabstop>
   <tabstop>locationEdit</tabstop>
   <tabstop>setLocationButton</tabstop>
+  <tabstop>spinPrefetchSize</tabstop>
   <tabstop>treeSyntaxHighlighting</tabstop>
   <tabstop>buttonBox</tabstop>
  </tabstops>
@@ -331,8 +352,8 @@
    <slot>showColourDialog(QTreeWidgetItem*,int)</slot>
    <hints>
     <hint type="sourcelabel">
-     <x>223</x>
+     <x>103</x>
-     <y>92</y>
+     <y>53</y>
     </hint>
     <hint type="destinationlabel">
      <x>395</x>

src/sqlitetablemodel.cpp

@@ -1,6 +1,6 @@
 #include "sqlitetablemodel.h"
 #include "sqlitedb.h"
-
+#include "PreferencesDialog.h"
 #include <QDebug>
 
 SqliteTableModel::SqliteTableModel(QObject* parent, DBBrowserDB* db)
@@ -9,7 +9,7 @@ SqliteTableModel::SqliteTableModel(QObject* parent, DBBrowserDB* db)
     , m_rowCount(0)
     , m_iSortColumn(0)
     , m_sSortOrder("ASC")
-    , m_chunkSize(50000)
+    , m_chunkSize(PreferencesDialog::getSettingsValue("db", "prefetchsize").toInt())
     , m_valid(false)
 {
 }