Elasticsearch实战:常见错误及详细解决方案
1.read_only_allow_delete":“true”
当我们在向某个索引添加一条数据的时候,可能(极少情况)会碰到下面的报错:
{"error": {"root_cause": [{"type": "cluster_block_exception","reason": "blocked by: [FORBIDDEN/12/index read-only / allow delete (api)];"}],"type": "cluster_block_exception","reason": "blocked by: [FORBIDDEN/12/index read-only / allow delete (api)];"},"status": 403
}
上述报错是说索引现在的状态是只读模式(read-only),如果查看该索引此时的状态:
GET z1/_settings
#结果如下
{"z1" : {"settings" : {"index" : {"number_of_shards" : "5","blocks" : {"read_only_allow_delete" : "true"},"provided_name" : "z1","creation_date" : "1556204559161","number_of_replicas" : "1","uuid" : "3PEevS9xSm-r3tw54p0o9w","version" : {"created" : "6050499"}}}}
}
可以看到"read_only_allow_delete" : "true"
,说明此时无法插入数据,当然,我们也可以模拟出来这个错误:
PUT z1
{"mappings": {"doc": {"properties": {"title": {"type":"text"}}}},"settings": {"index.blocks.read_only_allow_delete": true}
}PUT z1/doc/1
{"title": "es真难学"
}
现在我们如果执行插入数据,就会报开始的错误。那么怎么解决呢?
- 清理磁盘,使占用率低于 85%。
- 手动调整该项,具体参考官网
这里介绍一种,我们将该字段重新设置为:
PUT z1/_settings
{"index.blocks.read_only_allow_delete": null
}
现在再查看该索引就正常了,也可以正常的插入数据和查询了。
2. illegal_argument_exception
有时候,在聚合中,我们会发现如下报错:
{"error": {"root_cause": [{"type": "illegal_argument_exception","reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [age] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead."}],"type": "search_phase_execution_exception","reason": "all shards failed","phase": "query","grouped": true,"failed_shards": [{"shard": 0,"index": "z2","node": "NRwiP9PLRFCTJA7w3H9eqA","reason": {"type": "illegal_argument_exception","reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [age] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead."}}],"caused_by": {"type": "illegal_argument_exception","reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [age] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead.","caused_by": {"type": "illegal_argument_exception","reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [age] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead."}}},"status": 400
}
这是怎么回事呢?是因为,聚合查询时,指定字段不能是text
类型。比如下列示例:
PUT z2/doc/1
{"age":"18"
}
PUT z2/doc/2
{"age":20
}GET z2/doc/_search
{"query": {"match_all": {}},"aggs": {"my_sum": {"sum": {"field": "age"}}}
}
当我们向elasticsearch
中,添加一条数据时(此时,如果索引存在则直接新增或者更新文档,不存在则先创建索引),首先检查该age
字段的映射类型。如上示例中,我们添加第一篇文档时(z1
索引不存在),elasticsearch
会自动的创建索引,然后为age
字段创建映射关系(es 就猜此时age
字段的值是什么类型,如果发现是text
类型,那么存储该字段的映射类型就是text
),此时age
字段的值是text
类型,所以,第二条插入数据,age
的值也是text
类型,而不是我们看到的long
类型。我们可以查看一下该索引的mappings
信息:
GET z2/_mapping
#mapping信息如下
{"z2" : {"mappings" : {"doc" : {"properties" : {"age" : {"type" : "text","fields" : {"keyword" : {"type" : "keyword","ignore_above" : 256}}}}}}}
}
上述返回结果发现,age
类型是text
。而该类型又不支持聚合,所以,就会报错了。解决办法就是:
- 如果选择动态创建一篇文档,映射关系取决于你添加的第一条文档的各字段都对应什么类型。而不是我们看到的那样,第一次是
text
,第二次不加引号,就是long
类型了不是这样的。 - 如果嫌弃上面的解决办法麻烦,那就选择手动创建映射关系。首先指定好各字段对应什么类型。后续才不至于出错。
3.Result window is too large
很多时候,我们在查询文档时,一次查询结果很可能会有很多,而 elasticsearch 一次返回多少条结果,由size
参数决定:
GET e2/doc/_search
{"size": 100000,"query": {"match_all": {}}
}
而默认是最多范围一万条,那么当我们的请求超过一万条时(比如有十万条),就会报:
Result window is too large, from + size must be less than or equal to: [10000] but was [100000]. See the scroll api for a more efficient way to request large data sets. This limit can be set by changing the [index.max_result_window] index level setting.
意思是一次请求返回的结果太大,可以另行参考 scroll API
或者设置index.max_result_window
参数手动调整size
的最大默认值:
#kibana中设置
PUT e2/_settings
{"index": {"max_result_window": "100000"}
}
#Python中设置
from elasticsearch import Elasticsearch
es = Elasticsearch()
es.indices.put_settings(index='e2', body={"index": {"max_result_window": 100000}})
如上例,我们手动调整索引e2
的size
参数最大默认值到十万,这时,一次查询结果只要不超过 10 万就都会一次返回。 注意,这个设置对于索引es
的size
参数是永久生效的。
4.持续更新中
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