will_paginate 和 geokit 不当行为（双重查询）

Question

我正在使用 will_paginate 对 geokit 搜索结果进行分页。该代码可以工作，但是，在查看日志时，使用以下 will_paginate 调用时，它会加倍 geokit 查询：

@posts = Post.paginate :page => params[:page], :per_page => 1, 
                        :origin => @search, :within => @miles, :include => :user

这是原始的非分页调用，按预期工作（单个查询）：

@posts = Post.find(:all, :origin => @search, :within => @miles, :include => :user)

以下是使用时的日志输出第一个 will_paginate 调用：

Processing PostsController#search (for 127.0.0.1 at 2010-06-03 22:10:29) [POST]
  Parameters: {"commit"=>"Search", "action"=>"search", "authenticity_token"=>"K9Btfu6p7pz2mt+lWH0Fx0O7qj+0QY21JpfgyWT738I=", "controller"=>"posts", "location"=>"new york"}
Google geocoding. Address: new york. Result: <?xml version="1.0" encoding="UTF-8" ?>
<kml xmlns="http://earth.google.com/kml/2.0"><Response>
  <name>new york</name>
  <Status>
    <code>200</code>
    <request>geocode</request>
  </Status>
  <Placemark id="p1">
    <address>New York, NY, USA</address>
    <AddressDetails Accuracy="4" xmlns="urn:oasis:names:tc:ciq:xsdschema:xAL:2.0"><Country><CountryNameCode>US</CountryNameCode><CountryName>USA</CountryName><AdministrativeArea><AdministrativeAreaName>NY</AdministrativeAreaName><SubAdministrativeArea><SubAdministrativeAreaName>New York</SubAdministrativeAreaName><Locality><LocalityName>New York</LocalityName></Locality></SubAdministrativeArea></AdministrativeArea></Country></AddressDetails>
    <ExtendedData>
      <LatLonBox north="40.8494506" south="40.5788125" east="-73.7498541" west="-74.2620917" />
    </ExtendedData>
    <Point><coordinates>-74.0059729,40.7142691,0</coordinates></Point>
  </Placemark>
</Response></kml>
  Post Load (0.7ms)   SELECT *, 
 (ACOS(least(1,COS(0.710598048337988)*COS(-1.2916478932467)*COS(RADIANS(posts.lat))*COS(RADIANS(posts.lng))+
 COS(0.710598048337988)*SIN(-1.2916478932467)*COS(RADIANS(posts.lat))*SIN(RADIANS(posts.lng))+
 SIN(0.710598048337988)*SIN(RADIANS(posts.lat))))*3963.19)
 AS distance FROM `posts` WHERE (((posts.lat>40.352844467866 AND posts.lat<41.075693732134 AND posts.lng>-74.4827993840952 AND posts.lng<-73.5291464159048)) AND (
 (ACOS(least(1,COS(0.710598048337988)*COS(-1.2916478932467)*COS(RADIANS(posts.lat))*COS(RADIANS(posts.lng))+
 COS(0.710598048337988)*SIN(-1.2916478932467)*COS(RADIANS(posts.lat))*SIN(RADIANS(posts.lng))+
 SIN(0.710598048337988)*SIN(RADIANS(posts.lat))))*3963.19)
 <= 25)) LIMIT 0, 1
  Post Columns (2.4ms)   SHOW FIELDS FROM `posts`
  User Columns (2.2ms)   SHOW FIELDS FROM `users`
  User Load (0.4ms)   SELECT * FROM `users` WHERE (`users`.`id` = 1) 
Google geocoding. Address: new york. Result: <?xml version="1.0" encoding="UTF-8" ?>
<kml xmlns="http://earth.google.com/kml/2.0"><Response>
  <name>new york</name>
  <Status>
    <code>200</code>
    <request>geocode</request>
  </Status>
  <Placemark id="p1">
    <address>New York, NY, USA</address>
    <AddressDetails Accuracy="4" xmlns="urn:oasis:names:tc:ciq:xsdschema:xAL:2.0"><Country><CountryNameCode>US</CountryNameCode><CountryName>USA</CountryName><AdministrativeArea><AdministrativeAreaName>NY</AdministrativeAreaName><SubAdministrativeArea><SubAdministrativeAreaName>New York</SubAdministrativeAreaName><Locality><LocalityName>New York</LocalityName></Locality></SubAdministrativeArea></AdministrativeArea></Country></AddressDetails>
    <ExtendedData>
      <LatLonBox north="40.8494506" south="40.5788125" east="-73.7498541" west="-74.2620917" />
    </ExtendedData>
    <Point><coordinates>-74.0059729,40.7142691,0</coordinates></Point>
  </Placemark>
</Response></kml>
  SQL (0.4ms)   SELECT count(*) AS count_all FROM `posts` WHERE (((posts.lat>40.352844467866 AND posts.lat<41.075693732134 AND posts.lng>-74.4827993840952 AND posts.lng<-73.5291464159048)) AND (
 (ACOS(least(1,COS(0.710598048337988)*COS(-1.2916478932467)*COS(RADIANS(posts.lat))*COS(RADIANS(posts.lng))+
 COS(0.710598048337988)*SIN(-1.2916478932467)*COS(RADIANS(posts.lat))*SIN(RADIANS(posts.lng))+
 SIN(0.710598048337988)*SIN(RADIANS(posts.lat))))*3963.19)
 <= 25)) 
Rendering template within layouts/application

如您所见，KML/XML 和 SQL 查询增加了一倍。知道发生了什么事以及如何解决它吗？谢谢！

-托尼

Answer 1

实际上这是标准行为。 will_paginate首先统计记录数，然后检索20行，具体取决于可见页面和页面上的行数
（因此查询并不完全相同）。

需要计数来显示页数。

但是您的日志记录对我来说并不完全有意义，因为 will_paginate 查询会将数量限制为 20（或任何页面大小），而且显示的查询并不完全相同：例如，我看到不同的条件。