kaminari - Neo4j.rb - 使用 Kaminari 分页的索引太慢

Question

这是我的 Controller (索引已排序):

  def index
    if params[:limit]
      @bisacs = Bisac.order(:bisac_code).page(params[:page]).per(params[:limit])
    else
      @bisacs = Bisac.order(:bisac_code).page(params[:page])
    end
  end

这是执行的查询(在我看来太多而且太慢，第一页需要 6-7 秒或导航到下一页/最后一页:

Started GET "/bisacs" for 127.0.0.1 at 2015-08-11 13:16:33 -0400
Processing by BisacsController#index as HTML
  Rendered home/_main_links.html.erb (0.2ms)
 CYPHER 358ms MATCH (result_bisac:`Bisac`) RETURN count(result_bisac) AS result_bisac 
 CYPHER 389ms MATCH (result_bisac:`Bisac`) RETURN result_bisac ORDER BY result_bisac.bisac_code SKIP {skip_0} LIMIT {limit_25} | {:skip_0=>0, :limit_25=>25}
 CYPHER 119ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319299}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319299}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24320808}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24320808}
 CYPHER 120ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319262}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319262}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24320349}
 CYPHER 120ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24320349}
 CYPHER 120ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24318456}
 CYPHER 119ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24318456}
 CYPHER 119ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24320054}
 CYPHER 116ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24320054}
 CYPHER 119ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24321703}
 CYPHER 119ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24321703}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319503}
 CYPHER 117ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319503}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24321755}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24321755}
 CYPHER 116ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319313}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319313}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24321376}
 CYPHER 119ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24321376}
 CYPHER 119ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24321021}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24321021}
 CYPHER 123ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319280}
 CYPHER 119ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319280}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24318845}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24318845}
 CYPHER 122ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24320822}
 CYPHER 119ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24320822}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24318841}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24318841}
 CYPHER 119ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24321956}
 CYPHER 117ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24321956}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319031}
 CYPHER 119ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319031}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24320070}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24320070}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24322195}
 CYPHER 116ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24322195}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319124}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319124}
 CYPHER 119ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24322258}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24322258}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24318767}
 CYPHER 121ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24318767}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24320583}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24320583}
 CYPHER 118ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319086}
 CYPHER 117ms MATCH n WHERE (ID(n) = {ID_n}) WITH n RETURN ID(n) | {:ID_n=>24319086}
  Rendered bisacs/index.html.erb within layouts/application (6722.1ms)
Completed 200 OK in 7096ms (Views: 7095.5ms)

如何改进？为什么这25个节点要一个一个抓取？

在 Neo4j 控制台中检索所有 3983 代码仅需 1 秒左右:

MATCH (result_bisac:`Bisac`) RETURN result_bisac ORDER BY result_bisac.bisac_code;
Returned 3983 rows in 1064 ms, displaying first 1000 rows.

Answer 1

嗯，好的，所以这是另一个有点尴尬的答案；)

如果您将以下内容放入您的配置中(config/environments/development.rb 或 config/application.rb)它应该会修复它:

config.neo4j._active_record_destroyed_behavior = true

说明:gem 实现 ActiveNode#exists? 方法与 ActiveRecord#exists? 方法略有不同。在 ActiveRecord 中，它只是检查对象是否在内存中的某个点被销毁。在 ActiveNode 中，我们正在对实际数据库进行检查(也许我们在某些时候需要查询缓存)。

所以，长话短说，我们不想立即引入此更改，因为它是一个重大更改，所以我放入了一个配置变量来暂时修复它。配置变量在 6.0 版本中不应该是必需的