Add QgsApplication::maxConcurrentConnectionsPerPool()

python/core/auto_generated/qgsapplication.sip.in

@@ -797,6 +797,13 @@ Do not include generated variables (like system name, user name etc.)
 Set a single custom expression variable.
 
 .. versionadded:: 3.0
+%End
+
+    int maxConcurrentConnectionsPerPool() const;
+%Docstring
+The maximum number of concurrent connections per connections pool
+
+.. versionadded:: 3.4
 %End
 
 %If (ANDROID)

src/core/qgsapplication.cpp

@@ -85,6 +85,8 @@
 #include <cpl_conv.h> // for setting gdal options
 #include <sqlite3.h>
 
+#define CONN_POOL_MAX_CONCURRENT_CONNS      6
+
 QObject *ABISYM( QgsApplication::mFileOpenEventReceiver );
 QStringList ABISYM( QgsApplication::mFileOpenEventList );
 QString ABISYM( QgsApplication::mPrefixPath );
@@ -1461,6 +1463,10 @@ void QgsApplication::setCustomVariable( const QString &name, const QVariant &val
   emit instance()->customVariablesChanged();
 }
 
+int QgsApplication::maxConcurrentConnectionsPerPool() const
+{
+  return CONN_POOL_MAX_CONCURRENT_CONNS;
+}
 
 QString QgsApplication::nullRepresentation()
 {

src/core/qgsapplication.h

@@ -732,6 +732,13 @@ class CORE_EXPORT QgsApplication : public QApplication
      */
     static void setCustomVariable( const QString &name, const QVariant &value );
 
+    /**
+     * The maximum number of concurrent connections per connections pool
+     *
+     * \since QGIS 3.4
+     */
+    int maxConcurrentConnectionsPerPool() const;
+
 #ifdef SIP_RUN
     SIP_IF_FEATURE( ANDROID )
     //dummy method to workaround sip generation issue

src/core/qgsconnectionpool.h

@@ -19,6 +19,7 @@
 #define SIP_NO_FILE
 
 #include "qgis.h"
+#include "qgsapplication.h"
 #include <QCoreApplication>
 #include <QMap>
 #include <QMutex>
@@ -29,7 +30,6 @@
 #include <QThread>
 
 
-#define CONN_POOL_MAX_CONCURRENT_CONNS      6
 #define CONN_POOL_EXPIRATION_TIME           60    // in seconds
 
 
@@ -59,8 +59,6 @@ class QgsConnectionPoolGroup
 {
   public:
 
-    static const int MAX_CONCURRENT_CONNECTIONS;
-
     struct Item
     {
       T c;
@@ -69,7 +67,7 @@ class QgsConnectionPoolGroup
 
     QgsConnectionPoolGroup( const QString &ci )
       : connInfo( ci )
-      , sem( CONN_POOL_MAX_CONCURRENT_CONNS )
+      , sem( QgsApplication::instance()->maxConcurrentConnectionsPerPool() )
     {
     }