Question

下面是我的查询：

1.  SELECT META(m).id, m.sch_name AS name FROM `pricing_qa_1` AS m UNNEST m.pri_sch_ref AS r WHERE m.dtype = "mprisch" AND r  IN( SELECT  RAW META(a).id FROM `pricing_qa_1` AS a UNNEST a.prod_prof AS p UNNEST p.fx_prof AS f UNNEST f.spl_fx AS s WHERE a.dtype = "prisch" AND (f.fx_sch = "25" OR s.fx_sch = "25") ) ORDER BY LOWER(name) ASC

2.  SELECT META(m).id, m.sch_name AS name FROM `pricing_qa_1` AS m UNNEST m.pri_sch_ref AS r WHERE m.dtype = "mprisch" AND r  IN( SELECT  RAW META(a).id FROM `pricing_qa_1` AS a UNNEST a.prod_prof AS p WHERE a.dtype = "prisch" AND (p.prod_cd = "WMOBAC000A1") ) ORDER BY LOWER(name) ASC

显示结果需要2分钟。我需要了解如何调整可能的索引。

Answer 1

首先要尝试的是：

create index dtype_idx on pricing_qa_1(dtype)

您可以使用EXPLAIN the_query查看查询计划并找出正在使用的索引。

有关选择有效索引的更多信息，请尝试本文：

https://blog.couchbase.com/create-right-index-get-right-performance/

Answer 2

您可以尝试以下索引和查询。

CREATE INDEX ix1 ON pricing_qa_1 (LOWER(sch_name),  pri_sch_ref, sch_name) WHERE dtype = "mprisch";
CREATE INDEX ix2 ON pricing_qa_1 (DISTINCT ARRAY p.prod_cd FOR p IN prod_prof END) WHERE dtype = "prisch";

SELECT META(m).id, m.sch_name AS name
FROM `pricing_qa_1` AS m
WHERE m.dtype = "mprisch" AND LOWER(m.sch_name) IS NOT NULL
      AND ANY r IN m.pri_sch_ref SATISFIES r IN ( SELECT RAW META(a).id
                                                  FROM `pricing_qa_1` AS a
                                                  WHERE a.dtype = "prisch"
                                                        AND ANY p IN a.prod_prof SATISFIES p.prod_cd = "WMOBAC000A1" END)
ORDER BY LOWER(m.sch_name) ASC;

SELECT META(m).id, m.sch_name AS name
FROM `pricing_qa_1` AS m
WHERE m.dtype = "mprisch" AND LOWER(m.sch_name) IS NOT NULL
      AND ANY r IN m.pri_sch_ref SATISFIES r IN ( SELECT RAW META(a).id
                                                  FROM `pricing_qa_1` AS a
                                                  WHERE a.dtype = "prisch"
                                                        AND ANY p IN a.prod_prof SATISFIES
                                                                (ANY f IN p.fx_prof SATISFIES f.fx_sch = "25" OR
                                                                 "25" IN f.spl_fx[*].fx_sch END) END)
ORDER BY LOWER(m.sch_name) ASC;

如果子查询结果很小，您还可以尝试以下操作：

 1) Execute subquery first and get the results in application 
 2) Pass the right side of IN clause as query parameter from previous step and 
   execute query as adhoc=true
 3) change ix1 as array index https://docs.couchbase.com/server/6.0/n1ql/n1ql-language-reference/indexing-arrays.html

使用索引调整以下查询

2 个答案: