Query system data

InfluxDB Cloud Dedicated stores data related to queries, tables, partitions, and compaction in system tables in your cluster. Query data in your cluster’s system tables for information about your cluster.

• Query system tables
• System tables
• System query examples

Query system tables

Use the influxctl query command and SQL to query system tables. Provide the following:

• Enable system tables with the --enable-system-tables command flag.

• Database token: A database token with read permissions on the specified database. Uses the token setting from the influxctl connection profile or the --token command flag.

• Database name: The name of the database to query information about. Uses the database setting from the influxctl connection profile or the --database command flag.

• SQL query: The SQL query to execute. Pass the query in one of the following ways:

  • a string on the command line
  • a path to a file that contains the query
  • a single dash (-) to read the query from stdin

influxctl query \
  --enable-system-tables \
  --database 
DATABASE_NAME
 \
  --token 
DATABASE_TOKEN
 \
  "
SQL_QUERY
"

influxctl query \
  --enable-system-tables \
  --database 
DATABASE_NAME
 \
  --token 
DATABASE_TOKEN
 \
  /path/to/query.sql

cat ./query.sql | influxctl query \
  --enable-system-tables \
  --database 
DATABASE_NAME
 \
  --token 
DATABASE_TOKEN
 \
  - 

Replace the following:

• DATABASE_TOKEN: A database token with read access to the specified database
• DATABASE_NAME: The name of the database to query information about.
• SQL_QUERY: The SQL query to execute. For examples, see System query examples.

When prompted, enter y to acknowledge the potential impact querying system tables may have on your cluster.

System tables

• system.queries
• system.tables
• system.partitions
• system.compactor

system.queries

The system.queries table contains an unpersisted log of queries run against the current InfluxDB Querier to which your query is routed. The query log is specific to the current Querier and is not shared across Queriers in your cluster. Logs are scoped to the specified database.

system.tables

The system.tables table contains information about tables in the specified database.

system.partitions

The system.partitions table contains information about partitions associated with the specified database.

system.compactor

The system.compaction table contains information about compacted partition Parquet files associated with the specified database.

System query examples

• Query logs
  • View all stored query logs
  • View query logs for queries with end-to-end durations above a threshold
• Partitions
  • View partition templates of all tables
  • View the partition template of a specific table
  • View all partitions for a table
  • View the number of partitions per table
  • View the number of partitions for a specific table
• Storage usage
  • View the size of tables in megabytes
  • View the size of a specific table in megabytes
  • View the total size of all compacted partitions per table in bytes
  • View the total size of all compacted partitions in bytes
• Compaction
  • View overall compaction totals for each table
  • View overall compaction totals for a specific table

In the examples below, replace TABLE_NAME with the name of the table you want to query information about.

Query logs

View all stored query logs

SELECT * FROM system.queries

View query logs for queries with end-to-end durations above a threshold

The following returns query logs for queries with an end-to-end duration greater than 50 milliseconds.

SELECT * FROM system.queries WHERE end2end_duration::BIGINT > (50 * 1000000)

Partitions

View partition templates of all tables

SELECT * FROM system.tables

View the partition template of a specific table

SELECT * FROM system.tables WHERE table_name = '
TABLE_NAME
'

View all partitions for a table

SELECT * FROM system.partitions WHERE table_name = '
TABLE_NAME
'

View the number of partitions per table

SELECT
  table_name,
  COUNT(*) AS partition_count
FROM
  system.partitions
GROUP BY
  table_name

View the number of partitions for a specific table

SELECT
  COUNT(*) AS partition_count
FROM
  system.partitions
WHERE
  table_name = '
TABLE_NAME
'

Storage usage

View the size of tables in megabytes

SELECT
  table_name,
  SUM(total_size_mb) AS total_size_mb
FROM
  system.partitions
GROUP BY
  table_name

View the size of a specific table in megabytes

SELECT
  SUM(total_size_mb) AS total_size_mb
FROM
  system.partitions
WHERE
  table_name = '
TABLE_NAME
'

View the total size of all compacted partitions per table in bytes

SELECT
  table_name,
  SUM(total_l0_bytes) + SUM(total_l1_bytes) + SUM(total_l2_bytes) AS total_bytes
FROM
  system.compactor
GROUP BY
  table_name

View the total size of all compacted partitions in bytes

SELECT
  SUM(total_l0_bytes) + SUM(total_l1_bytes) + SUM(total_l2_bytes) AS total_bytes
FROM
  system.compactor

Compaction

View overall compaction totals for each table

SELECT
  table_name,
  SUM(total_l0_files) AS total_l0_files,
  SUM(total_l1_files) AS total_l1_files,
  SUM(total_l2_files) AS total_l2_files,
  SUM(total_l0_bytes) AS total_l0_bytes,
  SUM(total_l1_bytes) AS total_l1_bytes,
  SUM(total_l2_bytes) AS total_l2_bytes
FROM
  system.compactor
GROUP BY
  table_name

View overall compaction totals for a specific table

SELECT
  SUM(total_l0_files) AS total_l0_files,
  SUM(total_l1_files) AS total_l1_files,
  SUM(total_l2_files) AS total_l2_files,
  SUM(total_l0_bytes) AS total_l0_bytes,
  SUM(total_l1_bytes) AS total_l1_bytes,
  SUM(total_l2_bytes) AS total_l2_bytes
FROM
  system.compactor
WHERE
  table_name = '
TABLE_NAME
'