postgres provider: improve owner check (fixes #9844)

Author: jef-n

src/providers/postgres/qgspostgresconn.cpp

@@ -894,12 +894,15 @@ bool QgsPostgresConn::openCursor( QString cursorName, QString sql )
 {
   if ( mOpenCursors++ == 0 && !mTransaction )
   {
-    QgsDebugMsg( "Starting read-only transaction" );
-    PQexecNR( "BEGIN READ ONLY" );
+    QgsDebugMsg( QString( "Starting read-only transaction: %1" ).arg( mPostgresqlVersion ) );
+    if ( mPostgresqlVersion >= 80000 )
+      PQexecNR( "BEGIN READ ONLY" );
+    else
+      PQexecNR( "BEGIN" );
   }
   QgsDebugMsgLevel( QString( "Binary cursor %1 for %2" ).arg( cursorName ).arg( sql ), 3 );
   return PQexecNR( QString( "DECLARE %1 BINARY CURSOR %2 FOR %3" ).
-                   arg( cursorName ).arg( !mTransaction ? QString() : QString( "WITH HOLD" ) ).arg( sql ) );
+                   arg( cursorName ).arg( !mTransaction ? "" : QString( "WITH HOLD" ) ).arg( sql ) );
 }
 
 bool QgsPostgresConn::closeCursor( QString cursorName )

src/providers/postgres/qgspostgresprovider.cpp

@@ -976,10 +976,11 @@ bool QgsPostgresProvider::hasSufficientPermsAndCapabilities()
 
       sql = QString( "SELECT 1 FROM pg_class,pg_namespace WHERE "
                      "pg_class.relnamespace=pg_namespace.oid AND "
-                     "pg_get_userbyid(relowner)=current_user AND "
+                     "%3 AND "
                      "relname=%1 AND nspname=%2" )
             .arg( quotedValue( mTableName ) )
-            .arg( quotedValue( mSchemaName ) );
+            .arg( quotedValue( mSchemaName ) )
+            .arg( connectionRO()->pgVersion() < 80100 ? "pg_get_userbyid(relowner)=current_user" : "pg_has_role(relowner,'MEMBER')" );
       testAccess = connectionRO()->PQexec( sql );
       if ( testAccess.PQresultStatus() == PGRES_TUPLES_OK && testAccess.PQntuples() == 1 )
       {