Vector Match
vector match的含义如下
根据一定的规则，对两个vector的label进行匹配，如果匹配成功，则对两个vector进行运算
vector match有两种类型，一个是one to one，一个是one to many或者many to one
one to one
<vector expr> <bin-op> ignoring(<label list>) <vector expr>
<vector expr> <bin-op> on(<label list>) <vector expr>
bin-op 表示运算操作符，”+,-,/,*”等
ignoring 表示忽略某些label来关联两个vector
on 表示根据某些label来关联两个vector
例如vector1{label1,label2,label3}, vector2{label2,label3}, 则
ignoring(label1) 表示通过label2和label3对vector进行匹配
on(label2) 表示通过label2对vector进行匹配
下面以一个实际的例子来说明one to one 的vector match
原始数据如下
#vector1
method_code:http_errors:rate5m{method="get", code="500"} 24
method_code:http_errors:rate5m{method="get", code="404"} 30
method_code:http_errors:rate5m{method="put", code="501"} 3
method_code:http_errors:rate5m{method="post", code="500"} 6
method_code:http_errors:rate5m{method="post", code="404"} 21
#vector2
method:http_requests:rate5m{method="get"} 600
method:http_requests:rate5m{method="del"} 34
method:http_requests:rate5m{method="post"} 120
查询语句如下
method_code:http_errors:rate5m{code="500"} / ignoring(code) method:http_requests:rate5m
首先vector1的label有method，code，vector2的label有method，根据ignoring(code)可知，两个vector是根据method进行关联，可以得到下表所示的match结果
| vector1 | vector2 |
|---|---|
| method_code:http_errors:rate5m{method=”get”, code=”500”} 24 | method:http_requests:rate5m{method=”get”} 600 |
| method_code:http_errors:rate5m{method=”post”, code=”500”} 6 | method:http_requests:rate5m{method=”post”} 120 |
因此，查询结果如下所示：
{method="get"} 0.04 // 24 / 600
{method="post"} 0.05 // 6 / 120
上述查询语句等价于
method_code:http_errors:rate5m{code="500"} / on(method) method:http_requests:rate5m
one to many/many to one
<vector expr> <bin-op> ignoring(<label list>) group_left(<label list>) <vector expr>
<vector expr> <bin-op> ignoring(<label list>) group_right(<label list>) <vector expr>
<vector expr> <bin-op> on(<label list>) group_left(<label list>) <vector expr>
<vector expr> <bin-op> on(<label list>) group_right(<label list>) <vector expr>
group_left 表示many to one
group_right 表示one to many
下面还是以实际数据来说明，原始数据如下：
#vector1
method_code:http_errors:rate5m{method="get", code="500"} 24
method_code:http_errors:rate5m{method="get", code="404"} 30
method_code:http_errors:rate5m{method="put", code="501"} 3
method_code:http_errors:rate5m{method="post", code="500"} 6
method_code:http_errors:rate5m{method="post", code="404"} 21
#vector2
method:http_requests:rate5m{method="get"} 600
method:http_requests:rate5m{method="del"} 34
method:http_requests:rate5m{method="post"} 120
查询语句如下：
method_code:http_errors:rate5m / ignoring(code) group_left method:http_requests:rate5m
上述查询语句表示通过method对两个vector进行匹配，vector1存在两个method=get的metric，两个method=post的metric，vector2各存在一个method=get已经method的metric，所以match结果如下
| vector1 | vector2 |
|---|---|
| method_code:http_errors:rate5m{method=”get”, code=”500”} 24 | method:http_requests:rate5m{method=”get”} 600 |
| method_code:http_errors:rate5m{method=”get”, code=”404”} 30 | method:http_requests:rate5m{method=”get”} 600 |
| method_code:http_errors:rate5m{method=”post”, code=”500”} 6 | method:http_requests:rate5m{method=”post”} 120 |
| method_code:http_errors:rate5m{method=”post”, code=”404”} 21 | method:http_requests:rate5m{method=”post”} 120 |
查询结果如下
{method="get", code="500"} 0.04 // 24 / 600
{method="get", code="404"} 0.05 // 30 / 600
{method="post", code="500"} 0.05 // 6 / 120
{method="post", code="404"} 0.175 // 21 / 120
总结
对于one to one表达的是，vector1和vector2根据on或者ignoring中的label组成的值是唯一的，也就是说vector1和vector2根据label list，不存在两个相同的label value
对于group_left(label list)来说，vector1的label list组成的value可以有多个，而vector2的label list组成的value只能有一个，而group_right(label list)则相反，vector1的值只能有一个，而vector2的值可以有多个
