Meta functions

These functions provide table information including column details and metadata such as hysteresis parameters. These functions are particularly useful for checking if tables contain a designated timestamp column.

table_columns#

table_columns('tableName') returns the schema of a table

Arguments:

tableName is the name of an existing table as a string

Return value:

Returns a table with the following columns:

column - name of the available columns in the table
type - type of the column
indexed - if indexing is applied to this column
indexBlockCapacity - how many row IDs to store in a single storage block on disk
symbolCached - whether or not this symbol column is cached
symbolCapacity - how many distinct values this column of symbol type is expected to have
designated - if this is set as the designated timestamp column for this table

For more details on the meaning and use of these values, see the CREATE TABLE documentation.

Examples:

Get all columns in a table

table_columns('my_table')

column	type	indexed	indexBlockCapacity	symbolCached	symbolCapacity	designated
symb	SYMBOL	true	1048576	false	256	false
price	DOUBLE	false	0	false	0	false
ts	TIMESTAMP	false	0	false	0	true
s	STRING	false	0	false	0	false

Get designated timestamp column

SELECT column, type, designated FROM table_columns('my_table') WHERE designated

column	type	designated
ts	TIMESTAMP	true

Get the count of column types

SELECT type, count() FROM table_columns('my_table');

type	count
SYMBOL	1
DOUBLE	1
TIMESTAMP	1
STRING	1

tables#

tables() returns all tables in the database including table metadata.

Arguments:

tables() does not require arguments.

Return value:

Returns a table.

Examples:

List all tables

tables();

id	name	designatedTimestamp	partitionBy	o3MaxUncommittedRows	o3CommitHysteresisMicros
1	my_table	ts	DAY	500000	300000000
2	device_data	null	NONE	10000	30000000

All tables in reverse alphabetical order

tables() ORDER BY name DESC;

id	name	designatedTimestamp	partitionBy	o3MaxUncommittedRows	o3CommitHysteresisMicros
2	device_data	null	NONE	10000	30000000
1	my_table	ts	DAY	500000	300000000

All tables with a daily partitioning strategy

tables() WHERE partitionBy = 'DAY'

id	name	designatedTimestamp	partitionBy	o3MaxUncommittedRows	o3CommitHysteresisMicros
1	my_table	ts	DAY	500000	300000000