/get/records/bycolumn

URL: http://<db.host>:<db.port>/get/records/bycolumn

For a given table, retrieves the values from the requested column(s). Maps of column name to the array of values as well as the column data type are returned. This endpoint supports pagination with the input parameter offset and input parameter limit parameters.

Window functions, which can perform operations like moving averages, are available through this endpoint as well as /create/projection.

When using pagination, if the table (or the underlying table in the case of a view) is modified (records are inserted, updated, or deleted) during a call to the endpoint, the records or values retrieved may differ between calls based on the type of the update, e.g., the contiguity across pages cannot be relied upon.

If input parameter table_name is empty, selection is performed against a single-row virtual table. This can be useful in executing temporal (NOW()), identity (USER()), or constant-based functions (GEODIST(-77.11, 38.88, -71.06, 42.36)).

The response is returned as a dynamic schema. For details see: dynamic schemas documentation.

Input Parameter Description

Name

Type

Description

table_name

string

Name of the table or view on which this operation will be performed, in [schema_name.]table_name format, using standard name resolution rules. An empty table name retrieves one record from a single-row virtual table, where columns specified should be constants or constant expressions.

column_names

array of strings

The list of column values to retrieve.

offset

long

A positive integer indicating the number of initial results to skip (this can be useful for paging through the results). The default value is 0.The minimum allowed value is 0. The maximum allowed value is MAX_INT.

limit

long

A positive integer indicating the maximum number of results to be returned, or END_OF_SET (-9999) to indicate that the maximum number of results allowed by the server should be returned. The number of records returned will never exceed the server's own limit, defined by the max_get_records_size parameter in the server configuration. Use output parameter has_more_records to see if more records exist in the result to be fetched, and input parameter offset & input parameter limit to request subsequent pages of results. The default value is -9999.

encoding

string

Specifies the encoding for returned records; either binary or json. The default value is binary. The supported values are:

binary
json

options

map of string to strings

The default value is an empty map ( {} ).

Supported Parameters (keys)	Parameter Description
expression	Optional filter expression to apply to the table.
sort_by	Optional column that the data should be sorted by. Used in conjunction with sort_order. The order_by option can be used in lieu of sort_by / sort_order. The default value is ''.
sort_order	String indicating how the returned values should be sorted - ascending or descending. If sort_order is provided, sort_by has to be provided. The default value is ascending. The supported values are: ascending descending
order_by	Comma-separated list of the columns to be sorted by as well as the sort direction, e.g., 'timestamp asc, x desc'. The default value is ''.
convert_wkts_to_wkbs	If true, then WKT string columns will be returned as WKB bytes. The default value is false. The supported values are: true false
route_to_tom	For multihead record retrieval without shard key expression - specifies from which tom to retrieve data.

Output Parameter Description

The GPUdb server embeds the endpoint response inside a standard response structure which contains status information and the actual response to the query. Here is a description of the various fields of the wrapper:

Name

Type

Description

status

String

'OK' or 'ERROR'

message

String

Empty if success or an error message

data_type

String

'get_records_by_column_response' or 'none' in case of an error

data

String

Empty string

data_str

JSON or String

This embedded JSON represents the result of the /get/records/bycolumn endpoint:

Name	Type	Description
table_name	string	The same table name as was passed in the parameter list.
response_schema_str	string	Avro schema of output parameter binary_encoded_response or output parameter json_encoded_response.
binary_encoded_response	bytes	Avro binary encoded response.
json_encoded_response	string	Avro JSON encoded response.
total_number_of_records	long	Total/Filtered number of records.
has_more_records	boolean	Too many records. Returned a partial set.
info	map of string to strings	Additional information.

Empty string in case of an error.