Create External Table

Creates a new external table, which is a local database object whose source data is located externally to the database. The source data can be located either in KiFS; on the cluster, accessible to the database; or remotely, accessible via a pre-defined external data source.

The external table can have its structure defined explicitly, via input parameter create_table_options, which contains many of the options from Create Table; or defined implicitly, inferred from the source data.

Input Parameter Description

NameTypeDescription
table_namestringName of the table to be created, in [schema_name.]table_name format, using standard name resolution rules and meeting table naming criteria.
filepathsarray of stringsA list of file paths from which data will be sourced; For paths in KiFS, use the uri prefix of kifs:// followed by the path to a file or directory. File matching by prefix is supported, e.g. kifs://dir/file would match dir/file_1 and dir/file_2. When prefix matching is used, the path must start with a full, valid KiFS directory name. If an external data source is specified in datasource_name, these file paths must resolve to accessible files at that data source location. Prefix matching is supported. If the data source is hdfs, prefixes must be aligned with directories, i.e. partial file names will not match. If no data source is specified, the files are assumed to be local to the database and must all be accessible to the gpudb user, residing on the path (or relative to the path) specified by the external files directory in the Kinetica configuration file. Wildcards (*) can be used to specify a group of files. Prefix matching is supported, the prefixes must be aligned with directories. If the first path ends in .tsv, the text delimiter will be defaulted to a tab character. If the first path ends in .psv, the text delimiter will be defaulted to a pipe character (|).
modify_columnsmap of string to maps of string to stringsNot implemented yet. The default value is an empty map ( {} ).
create_table_optionsmap of string to strings

Options from Create Table , allowing the structure of the table to be defined independently of the data source. The default value is an empty map ( {} ).

Supported Parameters (keys)Parameter Description
type_idID of a currently registered type.
no_error_if_exists

If true, prevents an error from occurring if the table already exists and is of the given type. If a table with the same name but a different type exists, it is still an error. The default value is false. The supported values are:

  • true
  • false
is_replicated

Affects the distribution scheme for the table's data. If true and the given table has no explicit shard key defined, the table will be replicated. If false, the table will be sharded according to the shard key specified in the given type_id, or randomly sharded, if no shard key is specified. Note that a type containing a shard key cannot be used to create a replicated table. The default value is false. The supported values are:

  • true
  • false
foreign_keysSemicolon-separated list of foreign keys, of the format '(source_column_name [, ...]) references target_table_name(primary_key_column_name [, ...]) [as foreign_key_name]'.
foreign_shard_keyForeign shard key of the format 'source_column references shard_by_column from target_table(primary_key_column)'.
partition_type

Partitioning scheme to use.

Supported ValuesDescription
RANGEUse range partitioning.
INTERVALUse interval partitioning.
LISTUse list partitioning.
HASHUse hash partitioning.
SERIESUse series partitioning.
partition_keysComma-separated list of partition keys, which are the columns or column expressions by which records will be assigned to partitions defined by partition_definitions.
partition_definitionsComma-separated list of partition definitions, whose format depends on the choice of partition_type. See range partitioning, interval partitioning, list partitioning, hash partitioning, or series partitioning for example formats.
is_automatic_partition

If true, a new partition will be created for values which don't fall into an existing partition. Currently, only supported for list partitions. The default value is false. The supported values are:

  • true
  • false
ttlSets the TTL of the table specified in input parameter table_name.
chunk_sizeIndicates the number of records per chunk to be used for this table.
chunk_column_max_memoryIndicates the target maximum data size for each column in a chunk to be used for this table.
chunk_max_memoryIndicates the target maximum data size for all columns in a chunk to be used for this table.
is_result_table

Indicates whether the table is a memory-only table. A result table cannot contain columns with text_search data-handling, and it will not be retained if the server is restarted. The default value is false. The supported values are:

  • true
  • false
strategy_definitionThe tier strategy for the table and its columns.
optionsmap of string to strings

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

Supported Parameters (keys)Parameter Description
bad_record_table_nameName of a table to which records that were rejected are written. The bad-record-table has the following columns: line_number (long), line_rejected (string), error_message (string). When error_handling is abort, bad records table is not populated.
bad_record_table_limitA positive integer indicating the maximum number of records that can be written to the bad-record-table. The default value is '10000'.
bad_record_table_limit_per_inputFor subscriptions, a positive integer indicating the maximum number of records that can be written to the bad-record-table per file/payload. Default value will be bad_record_table_limit and total size of the table per rank is limited to bad_record_table_limit.
batch_sizeNumber of records to insert per batch when inserting data. The default value is '50000'.
column_formatsFor each target column specified, applies the column-property-bound format to the source data loaded into that column. Each column format will contain a mapping of one or more of its column properties to an appropriate format for each property. Currently supported column properties include date, time, & datetime. The parameter value must be formatted as a JSON string of maps of column names to maps of column properties to their corresponding column formats, e.g., '{ "order_date" : { "date" : "%Y.%m.%d" }, "order_time" : { "time" : "%H:%M:%S" } }'. See default_column_formats for valid format syntax.
columns_to_loadSpecifies a comma-delimited list of columns from the source data to load. If more than one file is being loaded, this list applies to all files. Column numbers can be specified discretely or as a range. For example, a value of '5,7,1..3' will insert values from the fifth column in the source data into the first column in the target table, from the seventh column in the source data into the second column in the target table, and from the first through third columns in the source data into the third through fifth columns in the target table. If the source data contains a header, column names matching the file header names may be provided instead of column numbers. If the target table doesn't exist, the table will be created with the columns in this order. If the target table does exist with columns in a different order than the source data, this list can be used to match the order of the target table. For example, a value of 'C, B, A' will create a three column table with column C, followed by column B, followed by column A; or will insert those fields in that order into a table created with columns in that order. If the target table exists, the column names must match the source data field names for a name-mapping to be successful. Mutually exclusive with columns_to_skip.
columns_to_skipSpecifies a comma-delimited list of columns from the source data to skip. Mutually exclusive with columns_to_load.
compression_type

Source data compression type The default value is auto.

Supported ValuesDescription
noneNo compression.
autoAuto detect compression type
gzipgzip file compression.
bzip2bzip2 file compression.
datasource_nameName of an existing external data source from which data file(s) specified in input parameter filepaths will be loaded
default_column_formatsSpecifies the default format to be applied to source data loaded into columns with the corresponding column property. Currently supported column properties include date, time, & datetime. This default column-property-bound format can be overridden by specifying a column property & format for a given target column in column_formats. For each specified annotation, the format will apply to all columns with that annotation unless a custom column_formats for that annotation is specified. The parameter value must be formatted as a JSON string that is a map of column properties to their respective column formats, e.g., '{ "date" : "%Y.%m.%d", "time" : "%H:%M:%S" }'. Column formats are specified as a string of control characters and plain text. The supported control characters are 'Y', 'm', 'd', 'H', 'M', 'S', and 's', which follow the Linux 'strptime()' specification, as well as 's', which specifies seconds and fractional seconds (though the fractional component will be truncated past milliseconds). Formats for the 'date' annotation must include the 'Y', 'm', and 'd' control characters. Formats for the 'time' annotation must include the 'H', 'M', and either 'S' or 's' (but not both) control characters. Formats for the 'datetime' annotation meet both the 'date' and 'time' control character requirements. For example, '{"datetime" : "%m/%d/%Y %H:%M:%S" }' would be used to interpret text as "05/04/2000 12:12:11"
error_handling

Specifies how errors should be handled upon insertion. The default value is abort.

Supported ValuesDescription
permissiveRecords with missing columns are populated with nulls if possible; otherwise, the malformed records are skipped.
ignore_bad_recordsMalformed records are skipped.
abortStops current insertion and aborts entire operation when an error is encountered. Primary key collisions are considered abortable errors in this mode.
external_table_type

Specifies whether the external table holds a local copy of the external data. The default value is materialized.

Supported ValuesDescription
materializedLoads a copy of the external data into the database, refreshed on demand
logicalExternal data will not be loaded into the database; the data will be retrieved from the source upon servicing each query against the external table
file_type

Specifies the type of the file(s) whose records will be inserted. The default value is delimited_text.

Supported ValuesDescription
avroAvro file format
delimited_textDelimited text file format; e.g., CSV, TSV, PSV, etc.
gdbEsri/GDB file format
jsonJson file format
parquetApache Parquet file format
shapefileShapeFile file format
flatten_columns

Specifies how to handle nested columns. The default value is false.

Supported ValuesDescription
trueBreak up nested columns to multiple columns
falseTreat nested columns as json columns instead of flattening
gdal_configuration_optionsComma separated list of gdal conf options, for the specific requets: key=value
ignore_existing_pk

Specifies the record collision error-suppression policy for inserting into a table with a primary key, only used when not in upsert mode (upsert mode is disabled when update_on_existing_pk is false). If set to true, any record being inserted that is rejected for having primary key values that match those of an existing table record will be ignored with no error generated. If false, the rejection of any record for having primary key values matching an existing record will result in an error being reported, as determined by error_handling. If the specified table does not have a primary key or if upsert mode is in effect (update_on_existing_pk is true), then this option has no effect. The default value is false.

Supported ValuesDescription
trueIgnore new records whose primary key values collide with those of existing records
falseTreat as errors any new records whose primary key values collide with those of existing records
ingestion_mode

Whether to do a full load, dry run, or perform a type inference on the source data. The default value is full.

Supported ValuesDescription
fullRun a type inference on the source data (if needed) and ingest
dry_runDoes not load data, but walks through the source data and determines the number of valid records, taking into account the current mode of error_handling.
type_inference_onlyInfer the type of the source data and return, without ingesting any data. The inferred type is returned in the response.
jdbc_fetch_sizeThe JDBC fetch size, which determines how many rows to fetch per round trip. The default value is '50000'.
kafka_consumers_per_rankNumber of Kafka consumer threads per rank (valid range 1-6). The default value is '1'.
kafka_group_idThe group id to be used when consuming data from a Kafka topic (valid only for Kafka datasource subscriptions).
kafka_offset_reset_policy

Policy to determine whether the Kafka data consumption starts either at earliest offset or latest offset. The default value is earliest. The supported values are:

  • earliest
  • latest
kafka_optimistic_ingest

Enable optimistic ingestion where Kafka topic offsets and table data are committed independently to achieve parallelism. The default value is false. The supported values are:

  • true
  • false
kafka_subscription_cancel_afterSets the Kafka subscription lifespan (in minutes). Expired subscription will be cancelled automatically.
kafka_type_inference_fetch_timeoutMaximum time to collect Kafka messages before type inferencing on the set of them.
layerGeo files layer(s) name(s): comma separated.
loading_mode

Scheme for distributing the extraction and loading of data from the source data file(s). This option applies only when loading files that are local to the database The default value is head.

Supported ValuesDescription
headThe head node loads all data. All files must be available to the head node.
distributed_sharedThe head node coordinates loading data by worker processes across all nodes from shared files available to all workers. NOTE: Instead of existing on a shared source, the files can be duplicated on a source local to each host to improve performance, though the files must appear as the same data set from the perspective of all hosts performing the load.
distributed_localA single worker process on each node loads all files that are available to it. This option works best when each worker loads files from its own file system, to maximize performance. In order to avoid data duplication, either each worker performing the load needs to have visibility to a set of files unique to it (no file is visible to more than one node) or the target table needs to have a primary key (which will allow the worker to automatically deduplicate data). NOTE: If the target table doesn't exist, the table structure will be determined by the head node. If the head node has no files local to it, it will be unable to determine the structure and the request will fail. If the head node is configured to have no worker processes, no data strictly accessible to the head node will be loaded.
local_time_offsetApply an offset to Avro local timestamp columns.
max_records_to_loadLimit the number of records to load in this request: if this number is larger than batch_size, then the number of records loaded will be limited to the next whole number of batch_size (per working thread).
num_tasks_per_rankNumber of tasks for reading file per rank. Default will be system configuration parameter, external_file_reader_num_tasks.
poll_intervalIf true, the number of seconds between attempts to load external files into the table. If zero, polling will be continuous as long as data is found. If no data is found, the interval will steadily increase to a maximum of 60 seconds. The default value is '0'.
primary_keysComma separated list of column names to set as primary keys, when not specified in the type.
refresh_method

Method by which the table can be refreshed from its source data. The default value is manual.

Supported ValuesDescription
manualRefresh only occurs when manually requested by invoking the refresh action of Alter Table on this table.
on_startRefresh table on database startup and when manually requested by invoking the refresh action of Alter Table on this table.
schema_registry_schema_nameName of the Avro schema in the schema registry to use when reading Avro records.
shard_keysComma separated list of column names to set as shard keys, when not specified in the type.
skip_linesSkip number of lines from begining of file.
subscribe

Continuously poll the data source to check for new data and load it into the table. The default value is false. The supported values are:

  • true
  • false
table_insert_mode

Insertion scheme to use when inserting records from multiple shapefiles. The default value is single.

Supported ValuesDescription
singleInsert all records into a single table.
table_per_fileInsert records from each file into a new table corresponding to that file.
text_comment_stringSpecifies the character string that should be interpreted as a comment line prefix in the source data. All lines in the data starting with the provided string are ignored. For delimited_text file_type only. The default value is '#'.
text_delimiterSpecifies the character delimiting field values in the source data and field names in the header (if present). For delimited_text file_type only. The default value is ','.
text_escape_characterSpecifies the character that is used to escape other characters in the source data. An 'a', 'b', 'f', 'n', 'r', 't', or 'v' preceded by an escape character will be interpreted as the ASCII bell, backspace, form feed, line feed, carriage return, horizontal tab, & vertical tab, respectively. For example, the escape character followed by an 'n' will be interpreted as a newline within a field value. The escape character can also be used to escape the quoting character, and will be treated as an escape character whether it is within a quoted field value or not. For delimited_text file_type only.
text_has_header

Indicates whether the source data contains a header row. For delimited_text file_type only. The default value is true. The supported values are:

  • true
  • false
text_header_property_delimiterSpecifies the delimiter for column properties in the header row (if present). Cannot be set to same value as text_delimiter. For delimited_text file_type only. The default value is '|'.
text_null_stringSpecifies the character string that should be interpreted as a null value in the source data. For delimited_text file_type only. The default value is '\N'.
text_quote_characterSpecifies the character that should be interpreted as a field value quoting character in the source data. The character must appear at beginning and end of field value to take effect. Delimiters within quoted fields are treated as literals and not delimiters. Within a quoted field, two consecutive quote characters will be interpreted as a single literal quote character, effectively escaping it. To not have a quote character, specify an empty string. For delimited_text file_type only. The default value is '"'.
text_search_columnsAdd 'text_search' property to internally inferenced string columns. Comma seperated list of column names or '*' for all columns. To add 'text_search' property only to string columns greater than or equal to a minimum size, also set the text_search_min_column_length
text_search_min_column_lengthSet the minimum column size for strings to apply the 'text_search' property to. Used only when text_search_columns has a value.
truncate_strings

If set to true, truncate string values that are longer than the column's type size. The default value is false. The supported values are:

  • true
  • false
truncate_table

If set to true, truncates the table specified by input parameter table_name prior to loading the file(s). The default value is false. The supported values are:

  • true
  • false
type_inference_mode

Optimize type inferencing for either speed or accuracy. The default value is speed.

Supported ValuesDescription
accuracyScans data to get exactly-typed & sized columns for all data scanned.
speedScans data and picks the widest possible column types so that 'all' values will fit with minimum data scanned
remote_queryRemote SQL query from which data will be sourced
remote_query_filter_columnName of column to be used for splitting remote_query into multiple sub-queries using the data distribution of given column
remote_query_increasing_columnColumn on subscribed remote query result that will increase for new records (e.g., TIMESTAMP).
remote_query_partition_columnAlias name for remote_query_filter_column.
update_on_existing_pk

Specifies the record collision policy for inserting into a table with a primary key. If set to true, any existing table record with primary key values that match those of a record being inserted will be replaced by that new record (the new data will be 'upserted'). If set to false, any existing table record with primary key values that match those of a record being inserted will remain unchanged, while the new record will be rejected and the error handled as determined by ignore_existing_pk & error_handling. If the specified table does not have a primary key, then this option has no effect. The default value is false.

Supported ValuesDescription
trueUpsert new records when primary keys match existing records
falseReject new records when primary keys match existing records

Output Parameter Description

NameTypeDescription
table_namestringValue of input parameter table_name.
type_idstringID of the currently registered table structure type for this external table
type_definitionstringA JSON string describing the columns of the created external table
type_labelstringThe user-defined description associated with the table's structure
type_propertiesmap of string to arrays of stringsA mapping of each external table column name to an array of column properties associated with that column
count_insertedlongNumber of records inserted into the external table.
count_skippedlongNumber of records skipped, when not running in abort error handling mode.
count_updatedlong[Not yet implemented] Number of records updated within the external table.
infomap of string to stringsAdditional information.
filesarray of strings