extjs 2.0 使用gridPanel加载数据特别慢

extjs 2.0 使用gridPanel加载数据特别慢，后台数据库（sql2008）一共才不到150条，绑定控件后加载时需要将尽2分钟，这是什么原因？网上找了好多的资料，都不行啊，数据绑定主要是通过store里的OnReadData="MyData_Refresh5"，然后调用 后台方法实现的 <ext:GridPanel ID="GridPanel4" runat="server" Title="<font style='font-size:13; font-weight:900; font-family: Arial,Tahoma, '微软雅黑';'>新蒜货源</font>"
                        Width="1240" Height="400" AutoHeight="true" AnchorHorizontal="100%" Cls="x-grid-custom">
                       
                        <Store>
                            <ext:Store ID="Store8" runat="server"  RemotePaging="false" OnReadData="MyData_Refresh5"
                                PageSize="100" >
                                <Proxy>
                                    <ext:PageProxy />
                                </Proxy>
                                <Model>
                                    <ext:Model ID="Model8" runat="server">
                                        <Fields>
                                            <ext:ModelField Name="SaleRecordID" />
                                            <ext:ModelField Name="SerialNo" />
                                            <ext:ModelField Name="LeftCount" />
                                            <ext:ModelField Name="Price" />
                                            <ext:ModelField Name="ProducingArea" />
                                            <ext:ModelField Name="SizeID" />
                                            <ext:ModelField Name="VillageID" />
                                            <ext:ModelField Name="TownID" />
                                            <ext:ModelField Name="Ifresale" />
                                            <ext:ModelField Name="StatusID" />
                                            <ext:ModelField Name="IsMildew" />
                                            <ext:ModelField Name="IsNew" />
                                            <ext:ModelField Name="Updatedatetime" />
                                            <ext:ModelField Name="KindID1" />
                                            <ext:ModelField Name="Rate60" />
                                            <ext:ModelField Name="Rate50" />
                                            <ext:ModelField Name="Rate55" />
                                            <ext:ModelField Name="RateUnder50" />
                                            <ext:ModelField Name="ProductRate" />
                                            <ext:ModelField Name="ColorAndLustreID" />
                                            <ext:ModelField Name="SurfaceID" />
                                            <ext:ModelField Name="SaleRecordsDetailID1" />
                                            <ext:ModelField Name="Deploydatetime" />
                                            <ext:ModelField Name="Packageid1" />
                                            <ext:ModelField Name="AccountType" />
                                            <ext:ModelField Name="LowPrice" />
                                            <ext:ModelField Name="TopPrice" />
                                            <ext:ModelField Name="ShowPrice" />
                                            <ext:ModelField Name="Amountofwater" />
                                            <ext:ModelField Name="CreditID" />
                                            <ext:ModelField Name="GermID" />
                                            <ext:ModelField Name="BadCloveID" />
                                        </Fields>
                                    </ext:Model>
                                </Model>
                            </ext:Store>
                        </Store>
                        
                        <ColumnModel ID="ColumnModel4" runat="server">
                            <Columns>
                                <%--<ext:RowNumbererColumn ID="RowNumbererColumn1" runat="server" Width="35" />--%>
                                <ext:Column ID="Column45" runat="server" Text="编号" DataIndex="SaleRecordID" Width="100"
                                    Align="Center" />
                                <%-- <ext:Column ID="Column46" runat="server" Text="序号" Width="60" DataIndex="SerialNo"
                                    Align="Center" Hidden="true">
                                </ext:Column>--%>
                                <ext:Column ID="Column32" runat="server" Text="县" Width="50" DataIndex="ProducingArea"
                                    Align="Center">
                                </ext:Column>
                                <ext:Column ID="Column39" runat="server" Text="乡/镇" Width="50" DataIndex="TownID"
                                    Align="Center">
                                </ext:Column>
                                <ext:Column ID="Column40" runat="server" Text="品种" Width="40" DataIndex="KindID1"
                                    Align="Center">
                                </ext:Column>
                                <ext:Column ID="Column44" runat="server" Text="干湿度" DataIndex="Amountofwater" Width="65"
                                    Align="Center">
                                </ext:Column>
                                <ext:Column ID="Column49" runat="server" Text="规格" Width="80" DataIndex="SizeID"
                                    Align="Center">
                                </ext:Column>
                                <ext:Column ID="Column60" runat="server" Text="6.0以上(%)" Width="75" DataIndex="Rate60"
                                    Align="Center">
                                </ext:Column>
                                <ext:Column ID="Column61" runat="server" Text="5.0以下(%)" Width="75" DataIndex="Rate50"
                                    Align="Center">
                                </ext:Column>
                                <ext:Column ID="Column62" runat="server" Text="成品率" Width="45" DataIndex="ProductRate"
                                    Align="Center">
                                </ext:Column>
                                <ext:Column ID="Column48" runat="server" Text="单价(元/斤)" Width="70" DataIndex="ShowPrice"
                                    Align="Center">
                                </ext:Column>
                                <ext:Column ID="Column47" runat="server" Text="吨数" Width="40" DataIndex="LeftCount"
                                    Align="Center">
                                </ext:Column>
                                <ext:Column ID="Column42" runat="server" Text="结算" DataIndex="AccountType" Width="40"
                                    Align="Center">
                                </ext:Column>
                               
                                <ext:Column ID="Column56" runat="server" Text="更新时间" DataIndex="Updatedatetime" Width="75"
                                    Align="Center">
                                </ext:Column>
                            </Columns>
                        </ColumnModel>
                 
                        
                        <View>
                            <ext:GridView ID="GridView4" runat="server" LoadingText="正在努力加载数据中..." />
                        </View>
                        <Plugins>
                            <ext:CellEditing ID="CellEditing2" runat="server" />
                        </Plugins>
                        <BottomBar>
                            <ext:PagingToolbar ID="PagingToolbar4" runat="server" />
                        </BottomBar>
                        
                    </ext:GridPanel>
                </Items>
            </ext:Panel>Ext JS