这个 Solr 范围过滤器查询有什么问题? [英] What's wrong with this Solr range filter query?

问题描述

以下过滤器查询返回零个结果(使用 *:* 作为查询):

The following filter query returns zero results (using *:* as query):

-startDate:[* TO *] OR startDate:[* TO NOW/DAY+1DAY]

但如果我只过滤:

-startDate:[* TO *]

我得到 3 个结果.

如果我只过滤:

startDate:[* TO NOW/DAY+1DAY]

我得到了 161 个结果.

I get 161 reults.

为什么合并的 FQ 返回零结果?我想要的是过滤器返回任何开始日期为空或开始日期在今天之前的文档.

Why is the combined FQ returning zero results? What I want is the filter to return any doc whose start date is null or start date is before today.

我使用的是 Solr 4.2.1.2013.03.26.08.26.55

I'm using Solr 4.2.1.2013.03.26.08.26.55

好吧，听起来很奇怪，一位同事建议像这样将括号放在两个部分上:

Well, strange it may sound a colleague suggested putting parenthesis on the two parts like this:

(-startDate:[* TO *]) OR (startDate:[* TO NOW/DAY+1DAY])

不知何故它奏效了.我仍然很好奇为什么这会有所不同.希望有人能有所启发.

And somehow it worked. I'm still curious why that made a difference. Hope someone can shed some light.

谢谢！

推荐答案

Solr 支持纯否定查询.他们这样做，本质上是通过将纯否定扩展为以下内容:

Solr supports pure negative queries. They do this, essentially, by expanding the pure negative to something like:

*:* -startDate:[* TO *]

但是，您将它组合到 BooleanQuery 中的内容，我认为它不再适用于这种逻辑.在 lucene 中，否定查询不会获取任何内容，而是过滤掉由其他肯定查询词带来的匹配项.这与 SQL 查询不同，SQL 查询在某种意义上以隐式 *:* 或完整的结果表开始，并允许您将其缩减.

However, what you combine it in a BooleanQuery, I don't believe it applies this sort of logic anymore. A negative query does not, in lucene, fetch anything, but rather filters out matches brought in by other, positive, query terms. This differs from SQL queries, which in a sense start with an implicit *:*, or a full table of results, and allow you to pare it down.

我相信您的 OR 实际上被忽略了，因为严格来说，它在上下文中没有意义.一般来说，OR 只是语法糖，我相信(field:this OR field:that 等价于 field:this field:that).

I believe your OR is effectively being ignored, since it doesn't, strictly speaking, make sense in context. Generally, OR is just syntactic sugar, I believe (field:this OR field:that is equivalent to field:this field:that).

因此，实际上您的查询是:startDate:[* TO NOW/DAY+1DAY] -startDate:[* TO *]，这使您看到的结果更加明显.当您将它括在括号中时，每个术语查询都会被单独处理，并且您可以访问 solr 对孤独否定查询的支持.

So, in effect your query is: startDate:[* TO NOW/DAY+1DAY] -startDate:[* TO *], which makes the results you see more obvious. When you wrap it in parentheses, then each term query is treated separately, and you gain access to solr's support of lonely negative queries.

如果您需要搜索未设置/空值，则更好的主意是存储一个默认值.*:* 以及像这样的扩展纯否定查询必须扫描整个索引，因此性能非常差.提供默认值将提高性能，并防止出现这种令人困惑的情况.

A much better idea is to store a default value, if you need to search for unset/null values. *:* and by extension pure negative queries like this have to scan the entire index, and so perform very poorly. Providing a default value will improve performance, and prevent this sort of confusing situation.

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