InfluxDB

Installation

Install Influx DB

# Red Hat/CentOS/Fedora
cat <<EOF | sudo tee /etc/yum.repos.d/influxdata.repo
[influxdata]
name = InfluxData Repository - Stable
baseurl = https://repos.influxdata.com/stable/\$basearch/main
enabled = 1
gpgcheck = 1
gpgkey = https://repos.influxdata.com/influxdata-archive_compat.key
EOF

yum install influxdb2

Install Influx CLI

從 InfluxDB 2.1 開始，influx CLI 與 influxDB 分開安裝與開發。

Download: Install and use the influx CLI | InfluxDB OSS 2.7 Documentation (influxdata.com)

# amd64
wget https://dl.influxdata.com/influxdb/releases/influxdb2-client-2.7.1-linux-amd64.tar.gz
tar xvzf path/to/influxdb2-client-2.7.1-linux-amd64.tar.gz
mv influx /usr/local/bin/

Start the service

systemctl start influxdb
systemctl status influxdb
systemctl enable influxdb

Set up and initialize DB (v2.7+)

Visit localhost:8086 in a browser
Create a user, bucket and organization names.
The API Tokens will be generated.
Copy the generated token and store it for safe keeping.

InfluxDB configuration

file: /etc/influxdb/config.{toml,yaml,yml,json}

# View the server configurations
influx server-config

config.toml:

bolt-path = "/var/lib/influxdb/influxd.bolt"
engine-path = "/var/lib/influxdb/engine"

Set up the influx CLI (v2.7+)

為了避免每次執行 influx CLI 指令時，需要重複做認證，透過 config create 可以將認證資訊儲存。

influx config create --config-name <config-name> \
  --host-url http://localhost:8086 \
  --org <your-org> \
  --token <your-auth-token> \
  --active
  
influx config ls

# Enter InfluxQL shell
influx v1 shell
> show databases
> quit

# View the server configuration
influx server-config

Schema Design

official tutorial: InfluxDB schema design

Data Elements

timstamp
measurement
tag key
tag value
field key
field value

Where to store data (tag or field)

tag value

資料型式只能是 string
資料長度不宜過長
資料唯一性的筆數不宜過多

field value

資料型式可以是 strings, floats, integers, or boolean。
NOTE: 如果是 strings，寫入資料時必須包含雙引號
不支援 GROUP BY 的查詢語法
適合儲存唯一性的資料
一次寫入多筆資料時，每筆的所有 field value 的組合不可有重複，否則會寫入失敗。
field 資料不會有 index，如果查詢的語法用到 field，效率會很差。

Management

For InfluxDB v2.7

influx v1 shell
> show databases
> quit

For InfluxDB v1.8

Create a new user and database

influx
> CREATE USER admin WITH PASSWORD 'adminpass' WITH ALL PRIVILEGES
> exit

influx -username admin -password adminpass
> set password for admin = 'newpass'
>
> create database mmap_nmon with duration 180d
> create user mon with password 'thisispassword'
> grant ALL on mmap_nmon to mon
> show GRANTS for mon

# In the shell
influx -username admin -password thisispass

# In the InfluxDB CLI
> auth
username:
password

InfluxQL

> show databases
name: databases
name
----
_internal
nmon_reports
nmon2influxdb_log

> show users
user  admin
----  -----
admin true
mon   false

> use nmon_reports
Using database nmon_reports
> show measurements
name: measurements
name
----
CPU_ALL
DISKAVGRIO
DISKAVGWIO
DISKBSIZE
DISKBUSY
DISKREAD
DISKREADSERV
DISKRIO
DISKRXFER
DISKSERV
...

Retention Policy

# for current database
> show retention policies
name    duration  shardGroupDuration replicaN default
----    --------  ------------------ -------- -------
autogen 8760h0m0s 168h0m0s           1        true

# for specified database
> show retention policies on nmon2influxdb_log
name          duration shardGroupDuration replicaN default
----          -------- ------------------ -------- -------
autogen       0s       168h0m0s           1        false
log_retention 48h0m0s  24h0m0s            1        true

# Create a policy
> CREATE RETENTION POLICY "one_day_only" ON "NOAA_water_database" DURATION 1d REPLICATION 1

# Alter the policy
> ALTER RETENTION POLICY "what_is_time" ON "NOAA_water_database" DURATION 3w SHARD DURATION 2h DEFAULT

# Delete a policy
> DROP RETENTION POLICY "what_is_time" ON "NOAA_water_database"

Verify the account

curl -G http://localhost:8086/query -u mon:thisispassword --data-urlencode "q=SHOW DATABASES"
{"results":[{"statement_id":0,"series":[{"name":"databases","columns":["name"],"values":[["mmap_nmon"]]}]}]}

查詢表資訊

SHOW MEASUREMENTS  --查詢當前資料庫中含有的表
SHOW FIELD KEYS --查看當前資料庫所有表的欄位
show field keys from <measurement-name>
SHOW series from pay --查看key數據
SHOW TAG KEYS FROM "pay" --查看key中tag key值
SHOW TAG VALUES FROM "pay" WITH KEY = "merId" --查看key中tag 指定key值對應的值
SHOW TAG VALUES FROM cpu WITH KEY IN ("region", "host") WHERE service = 'redis'
DROP SERIES FROM  WHERE ='' --刪除key
SHOW CONTINUOUS QUERIES   --查看連續執行命令
SHOW QUERIES  --查看最後執行命令
KILL QUERY  --結束命令
SHOW RETENTION POLICIES ON mydb  --查看保留數據
show series cardinality on mydb --資料庫總筆數

查詢資料

SELECT * FROM /.*/ LIMIT 1  --查詢當前資料庫下所有表的第一行記錄
select * from pay  order by time desc limit 2
select * from  db_name."POLICIES name".measurement_name --指定查詢資料庫下資料保留中的表資料 POLICIES name資料保留

刪除資料

delete from "query" --刪除表所有資料，則表就不存在了
drop MEASUREMENT "query"   --刪除表（注意會把資料保留刪除使用delete不會）
DELETE FROM cpu
DELETE FROM cpu WHERE time < '2000-01-01T00:00:00Z'
DELETE WHERE time < '2000-01-01T00:00:00Z'
DROP DATABASE “testDB” --刪除資料庫
DROP RETENTION POLICY "dbbak" ON mydb --刪除保留資料為dbbak資料
DROP SERIES from pay where tag_key='' --刪除key中的tag

函數使用

mean: 平均值
sum: 總和
min: 最小值
max: 最大值
count: 總個數
difference: 差異數 (前後筆資料的比較)
non_negative_difference: 正差異數 (前後筆資料的比較)

select * from pay   order by time desc limit 2
select mean(allTime) from pay where time >= today() group by time(10m) time_zone(+8)
select * from pay time_zone(+8) limit 2
SELECT sum(allTime) FROM "pay" WHERE time > now() - 10s
select count(allTime) from pay  where time > now() - 10m  group by time(1s)

select difference("commit_sql") from "snapdb2" where time > now() - 1h limit 10
select non_negative_difference(*) from "snapdb2" where time > now() - 1h limit 10
select non_negative_difference(/commit_sql|rollback_sql/) from "snapdb2" where time > now() - 1h limit 10

User and Privileges

> CREATE USER "todd" WITH PASSWORD '123456'

> SHOW GRANTS for "todd"

> SET PASSWORD FOR "todd" = 'newpassword'

> GRANT READ ON "NOAA_water_database" TO "todd"
> GRANT ALL ON "NOAA_water_database" TO "todd"

> REVOKE ALL PRIVILEGES FROM "todd"
> REVOKE ALL ON "NOAA_water_database" FROM "todd"
> REVOKE WRITE ON "NOAA_water_database" FROM "todd"

> DROP USER "todd"

Covert timestamp to normal datetime

influx -precision rfc3339
# Or, in CLI
> precision rfc3339

Convert InfluxData to csv format

# With CLI
# There is also useful -precision option to set format of timestamp.
influx -database 'database_name' -execute "SELECT * FROM table_name" -format csv > test.csv

influx -username your_user_if_any -password "secret!" -database 'db_name' -host 'localhost' -execute 'SELECT * FROM "db_name"."your_retention_policy_or_nothing"."your_measurement_name" WHERE time > '\''2017-09-05'\'' and time < '\''2017-09-05T23:59:59Z'\'' AND other_conditions_if_required' -format 'csv' > /tmp/your_measurement_name_20170905.csv

# With HTTP-API
# Samples:
# "q=SELECT * FROM \"mymeasurement\" where time > now() - 130d"
# "q=SELECT * FROM \"mymeasurement\" where (time < now() - 130d) and  (time > now() - 260d)"
curl -G 'http://localhost:8086/query' --data-urlencode "db=mydb" --data-urlencode "epoch=#timeunit" --data-urlencode "q=SELECT * FROM \"mymeasurement\" " -H "Accept: application/csv" >  mytargetcsv.csv

Tag Query

> show tag values from {measurement} with key={key}
> show tag values from {measurement} with key={key} where {tag-key}={tag-value}

Services

systemctl start influxdb
systemctl enable influxdb

Learning

[Influxdb] influxdb命令使用