mongoDB .Net,Asp.Net高效分页类

最近在研究mongodb，发现她的性能比mysql好很多，但具体快多少还没有测试过。

项目组最近在策划新的游戏，我们程序都开始准备相关的东西，首先是游戏的后台，由于用mongodb，所以整个框架都得重新写过，分页类也不例外。本来分页是用skip+limit的，但有一次我不知道手哪里痒了，弄了100w数据进去，发现这种分页方法的效率骤然下降，从第一页翻到最后一页竟然要0.9s，而且只是100w数据，效率实在太低了，因为考虑到操作日志，消费日志这些大表，百万级数据是很正常的事情，所以这样的分页是伤不起的，所以我决定改进一下分页的算法。

从网上找到资料，原来对于大数据量的分页，都不用skip+limit的，是通过改变查询规则来起到分页的效果。由于不用略过，所以无聊数据量有多大，时间复杂度的波动不大。

这个是根据，实现原理是通过数据库主键ID来进行查询分页

　　 //操作数据库帮助类

protected MongoDBConnector_Local_NoAuth conn = new MongoDBConnector_Local_NoAuth();

//存放分页连对应主键ID，然后通过ID进行查询
protected Dictionary<int, int> docId = new Dictionary<int, int>();

/// <summary>
 /// 获取数据并进行分页计算
 /// </summary>
 /// <param name="t">这个用户查询</param>
 /// <param name="PageSize">分页大小</param>
 /// <param name="CurrentPageIndex">当前页数</param>
 /// <param name="PageLink">分页的页面：比如Default.aspx</param>
 /// <param name="homepage">这个是输出参数，输出分页连</param>
 /// <returns>查询到数据</returns>

public IList<Answer> GetList(string t, int PageSize, int CurrentPageIndex, string PageLink, out string homepage)
 {
 //获取数据库
 MongoDatabase database = conn.DataBase_Select_ReturnDB("Ask");
 //获取数据
 MongoCollection<Answer> mcollection = database.GetCollection<Answer>("Answer");
 QueryConditionList query = null;//定义查询条件
 int id = 0;
 object obj = HttpContext.Current.Session["ids"];//读取缓存数据

//缓存为空，重新开始查询
 if (object.Equals(obj, null))
 {
 query = Query.GT("ID", 0);
 }//分页连处理
 else if (CurrentPageIndex ==1)
 {
 query = Query.GT("ID", 0);
 }
 else
 {//读取条件生成查询
 Dictionary<int, int> docKey = obj as Dictionary<int, int>;
 id = docKey[CurrentPageIndex];
 query = Query.GT("ID", id);
 }
 int recordCount = Convert.ToInt32(mcollection.Count());
 int mpage = recordCount / PageSize + (recordCount % PageSize > 0 ? 1 : 0);
 int PageNo = Math.Min(Convert.ToInt32(start) / PageSize + 1, mpage);
 homepage = PageLink_aspx(PageLink, t, CurrentPageIndex, recordCount, mpage);
 MongoCursor<Answer> mcursor = mcollection.Find(query).SetLimit(20).SetSortOrder(SortBy.Ascending("ID"));
 //判断1到6页不变
 if (CurrentPageIndex - 6 <= 0)
 {
 query = Query.GT("ID", 1);
 IList<Answer> alist = mcollection.Find(query).SetLimit(220).SetSortOrder(SortBy.Ascending("ID")).ToList<Answer>();
 int cnt = alist.Count();
 int index = 0;
 int page = cnt / 20;
 for (int i = 0; i < page; i++)
 {
 index = i + 1;
 docId.Add(index, alist[i * 20].ID);
 }
 int ys = cnt % 20;
 if (ys != 0)
 docId.Add(index + 1, alist[cnt - ys].ID);
 HttpContext.Current.Session["ids"] = docId;
 }
 else
 {
 //处理左边数据
 docId.Clear();
 query = Query.LTE("ID", id);
 IList<Answer> alist_left = mcollection.Find(query).SetLimit(120).SetSortOrder(SortBy.Descending("ID")).ToList<Answer>();
 int start_left = CurrentPageIndex - 6;
 int cnt_left = alist_left.Count;
 int page_left = cnt_left / 20;
 for (int i = page_left-1; i>=0; i--)
 {
 start_left = start_left + 1;
 docId.Add(start_left, alist_left[i * 20].ID);
 }
 int ys_left = cnt_left % 20;
 if (ys_left != 0)
 docId.Add(start_left + 1, alist_left[cnt_left - ys_left].ID);
 //获取分页连右边数据
 query = Query.GT("ID", id);
 IList<Answer> alist_right = mcollection.Find(query).SetLimit(120).SetSortOrder(SortBy.Ascending("ID")).ToList<Answer>();
 int start_right = start_left;
 int cnt_right = alist_right.Count;
 int page_right = cnt_right / 20;
 for (int i = 0; i < page_right; i++)
 {
 if (i == 0)
 continue;
 start_right = start_right + 1;
 docId.Add(start_right, alist_right[i * 20].ID);
 }
 int ys_right = cnt_left % 20;
 if (ys_left != 0)
 docId.Add(start_right + 1, alist_right[cnt_right - ys_right].ID);
 HttpContext.Current.Session["ids"] = docId;
 }
 return mcursor.ToList<Answer>();
 }
 /// <summary>
 /// 动态分页链接
 /// </summary>
 /// <param name="HomePageStr">分页页面名称</param>
 /// <param name="t">查询条件做URL地址进行传参</param>
 /// <param name="PageNo">当前页数</param>
 /// <param name="totalCnt">总记录数</param>
 /// <param name="mpage">总页数</param>
 /// <returns></returns>
 public string PageLink_aspx(string HomePageStr, string t, int PageNo, int totalCnt, int mpage)
 {
 int i, j, k;
 string homelink;
 string homepage;
 homepage = "";
 homelink = HomePageStr
;
 homepage = homepage + "第 " + (PageNo).ToString() + " / " + mpage.ToString() + " 页  共" + totalCnt + "条 ";
 if (PageNo > 1)
 {
 homepage += " <a href=\"" + homelink + "?start=1" + t + "\">首页</a> ";
 homepage = homepage + " <a href=\"" + homelink + "?start=" + Convert.ToString((PageNo - 1)) + t + "\">上一页 </a> ";
 }
 else { homepage = homepage + " 上一页 "; }
 if (PageNo <= 5)
 {
 i = 1;
 }
 else
 {
 i = PageNo - 5;
 }
 k = i + 10;
 if (k > mpage) { k = mpage; }
 for (j = i; j <= k; j++)
 {
 if (j == PageNo) { homepage = homepage + "" + Convert.ToString(j) + " "; }
 else if (j == 1) { homepage = homepage + "<a href=\"" + homelink + "?start=1" + t + "\" >[" + Convert.ToString(j) + "]</a> "; }
 else { homepage = homepage + "<a href=\"" + HomePageStr + "?start=" + j + t + "\">[" + Convert.ToString(j) + "]</a> "; }
 }
 if (PageNo < mpage)
 {
 homepage = homepage + " <a href=\"" + HomePageStr + "?start=" + Convert.ToString((PageNo + 1)) + t + "\">下一页</a> ";
 homepage += " <a href=\"" + HomePageStr + "?start=" + mpage + t + "\">最后一页</a> ";
 }
 else { homepage = homepage + " 下一页 "; }
 return homepage;
 }

//其实还有一个功能没有实现，由于时间关系，最后一页我没有实现，相信大家看到这里，应该可以自己实现最后一页了哈

posted @ 2012-03-29 00:41 yuanchun 阅读(1288) 评论(0) 收藏举报

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mongoDB .Net,Asp.Net高效分页类

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