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我正在执行一个 influxSQL 查询，该查询在 1 分钟内返回结果。询问 ：

select SUM(call_duration) as total_duration,Count(Distinct(recipient_id)) as total_recipients from xyz where target_id = '1';

单独的查询，如

select Count(Distinct(recipient_id)) as total_recipients from xyz where target_id = '1';

select SUM(call_duration) as total_duration from xyz where target_id = '1';

也需要超过 1 分钟才能返回。

而查询

select MAX(call_duration), MIN(call_duration) from xyz where target_id = '1';

返回结果非常快，在几秒钟内，如 3-4 秒。

表（测量值）xyz 非常大。有超过 1000 万条记录符合这个 where 条件。call_duration 和 recipient_id 是 Fields 而 target_id 是 Tag

虽然 MIN 和 MAX 函数返回结果非常快，但我怀疑为什么 SUM 需要更多时间？

InfluxDB 版本：1.7.4 机器配置 - AWS EC2 - t2.medium（4 GB RAM）

配置文件：

[meta]
dir = "/var/lib/influxdb/meta"
[data]
dir = "/var/lib/influxdb/data"
wal-dir = "/var/lib/influxdb/wal"
series-id-set-cache-size = 100
[coordinator]
[retention]
[shard-precreation]
[monitor]
[http]
enabled = true
auth-enabled = true
log-enabled = true
access-log-path = "/var/log/influxdb/http_access.log"
write-tracing = false
max-body-size = 0
max-concurrent-write-limit = 0
[logging]
[subscriber]
[[graphite]]
[[collectd]]
[[opentsdb]]
[[udp]]
[continuous_queries]
[tls]

我认为结果应该在 5-6 秒内返回

EXPLAIN select MIN(call_duration) from xyz where target_id='1';
QUERY PLAN
----------
EXPRESSION: min(call_duration::float)
NUMBER OF SHARDS: 21
NUMBER OF SERIES: 85134
CACHED VALUES: 0
NUMBER OF FILES: 24642
NUMBER OF BLOCKS: 31608
SIZE OF BLOCKS: 65520278

EXPLAIN select MAX(call_duration) from xyz where target_id='1';
QUERY PLAN
----------
EXPRESSION: max(call_duration::float)
NUMBER OF SHARDS: 21
NUMBER OF SERIES: 85134
CACHED VALUES: 0
NUMBER OF FILES: 24642
NUMBER OF BLOCKS: 31608
SIZE OF BLOCKS: 65520278

EXPLAIN select SUM(call_duration) as total_call_duration from xyz where target_id='1';
QUERY PLAN
----------
EXPRESSION: sum(call_duration::float)
NUMBER OF SHARDS: 21
NUMBER OF SERIES: 85134
CACHED VALUES: 0
NUMBER OF FILES: 24642
NUMBER OF BLOCKS: 31608
SIZE OF BLOCKS: 65520278

EXPLAIN select Count(Distinct(recipient_id)) as total_recipients from xyz where target_id='1';
QUERY PLAN
----------
EXPRESSION: recipient_id::integer
NUMBER OF SHARDS: 21
NUMBER OF SERIES: 85134
CACHED VALUES: 0
NUMBER OF FILES: 24642
NUMBER OF BLOCKS: 31608
SIZE OF BLOCKS: 82448255
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