gpload

Control File Format

The gpload control file uses the YAML 1.1 document format and then implements its own schema for defining the various steps of a Greenplum Database load operation. The control file must be a valid YAML document.

The gpload program processes the control file document in order and uses indentation (spaces) to determine the document hierarchy and the relationships of the sections to one another. The use of white space is significant. White space should not be used simply for formatting purposes, and tabs should not be used at all.

The basic structure of a load control file is:

--- VERSION: 1.0.0.1 DATABASE: db_name USER: db_username HOST: master_hostname PORT: master_port GPLOAD: INPUT: - SOURCE: LOCAL_HOSTNAME: - hostname_or_ip PORT: http_port | PORT_RANGE: [start_port_range, end_port_range] FILE: - /path/to/input_file SSL: true | false CERTIFICATES_PATH: /path/to/certificates - FULLY_QUALIFIED_DOMAIN_NAME: true | false - COLUMNS: - field_name: data_type - TRANSFORM: 'transformation' - TRANSFORM_CONFIG: 'configuration-file-path' - MAX_LINE_LENGTH: integer - FORMAT: text | csv - DELIMITER: 'delimiter_character' - ESCAPE: 'escape_character' | 'OFF' - NULL_AS: 'null_string' - FILL_MISSING_FIELDS: true | false - FORCE_NOT_NULL: true | false - QUOTE: 'csv_quote_character' - HEADER: true | false - ENCODING: database_encoding - ERROR_LIMIT: integer - LOG_ERRORS: true | false EXTERNAL: - SCHEMA: schema | '%' OUTPUT: - TABLE: schema.table_name - MODE: insert | update | merge - MATCH_COLUMNS: - target_column_name - UPDATE_COLUMNS: - target_column_name - UPDATE_CONDITION: 'boolean_condition' - MAPPING: target_column_name: source_column_name | 'expression' PRELOAD: - TRUNCATE: true | false - REUSE_TABLES: true | false - STAGING_TABLE: external_table_name - FAST_MATCH: true | false SQL: - BEFORE: "sql_command" - AFTER: "sql_command" VERSION Optional. The version of the gpload control file schema. The current version is 1.0.0.1. DATABASE Optional. Specifies which database in the Greenplum Database system to connect to. If not specified, defaults to $PGDATABASE if set or the current system user name. You can also specify the database on the command line using the -d option. USER Optional. Specifies which database role to use to connect. If not specified, defaults to the current user or $PGUSER if set. You can also specify the database role on the command line using the -U option. If the user running gpload is not a Greenplum Database superuser, then the appropriate rights must be granted to the user for the load to be processed. See the Greenplum Database Reference Guide for more information. HOST Optional. Specifies Greenplum Database master host name. If not specified, defaults to localhost or $PGHOST if set. You can also specify the master host name on the command line using the -h option. PORT Optional. Specifies Greenplum Database master port. If not specified, defaults to 5432 or $PGPORT if set. You can also specify the master port on the command line using the -p option. GPLOAD Required. Begins the load specification section. A GPLOAD specification must have an INPUT and an OUTPUT section defined. INPUT Required. Defines the location and the format of the input data to be loaded. gpload will start one or more instances of the file distribution program on the current host and create the required external table definition(s) in Greenplum Database that point to the source data. Note that the host from which you run gpload must be accessible over the network by all Greenplum Database hosts (master and segments). SOURCE Required. The SOURCE block of an INPUT specification defines the location of a source file. An INPUT section can have more than one SOURCE block defined. Each SOURCE block defined corresponds to one instance of the file distribution program that will be started on the local machine. Each SOURCE block defined must have a FILE specification.

For more information about using the gpfdist parallel file server and single and multiple gpfdist instances, see .

LOCAL_HOSTNAME Optional. Specifies the host name or IP address of the local machine on which gpload is running. If this machine is configured with multiple network interface cards (NICs), you can specify the host name or IP of each individual NIC to allow network traffic to use all NICs simultaneously. The default is to use the local machine's primary host name or IP only. PORT Optional. Specifies the specific port number that the file distribution program should use. You can also supply a PORT_RANGE to select an available port from the specified range. If both PORT and PORT_RANGE are defined, then PORT takes precedence. If neither PORT or PORT_RANGE are defined, the default is to select an available port between 8000 and 9000.

If multiple host names are declared in LOCAL_HOSTNAME, this port number is used for all hosts. This configuration is desired if you want to use all NICs to load the same file or set of files in a given directory location.

PORT_RANGE Optional. Can be used instead of PORT to supply a range of port numbers from which gpload can choose an available port for this instance of the file distribution program. FILE Required. Specifies the location of a file, named pipe, or directory location on the local file system that contains data to be loaded. You can declare more than one file so long as the data is of the same format in all files specified.

If the files are compressed using gzip or bzip2 (have a .gz or .bz2 file extension), the files will be uncompressed automatically (provided that gunzip or bunzip2 is in your path).

When specifying which source files to load, you can use the wildcard character (*) or other C-style pattern matching to denote multiple files. The files specified are assumed to be relative to the current directory from which gpload is executed (or you can declare an absolute path).

SSL Optional. Specifies usage of SSL encryption. If SSL is set to true, gpload starts the gpfdist server with the --ssl option and uses the gpfdists:// protocol. CERTIFICATES_PATH Required when SSL is true; cannot be specified when SSL is false or unspecified. The location specified in CERTIFICATES_PATH must contain the following files:

The server certificate file, server.crt
The server private key file, server.key
The trusted certificate authorities, root.crt

The root directory (/) cannot be specified as CERTIFICATES_PATH.

FULLY_QUALIFIED_DOMAIN_NAME Optional. Specifies whether gpload resolve hostnames to the fully qualified domain name (FQDN) or the local hostname. If the value is set to true, names are resolved to the FQDN. If the value is set to false, resolution is to the local hostname. The default is false.

A fully qualified domain name might be required in some situations. For example, if the Greenplum Database system is in a different domain than an ETL application that is being accessed by gpload.

COLUMNS Optional. Specifies the schema of the source data file(s) in the format of field_name:data_type. The DELIMITER character in the source file is what separates two data value fields (columns). A row is determined by a line feed character (0x0a).

If the input COLUMNS are not specified, then the schema of the output TABLE is implied, meaning that the source data must have the same column order, number of columns, and data format as the target table.

The default source-to-target mapping is based on a match of column names as defined in this section and the column names in the target TABLE. This default mapping can be overridden using the MAPPING section.

TRANSFORM Optional. Specifies the name of the input transformation passed to gpload. For information about XML transformations, see "Loading and Unloading Data" in the Greenplum Database Administrator Guide. TRANSFORM_CONFIG Required when TRANSFORM is specified. Specifies the location of the transformation configuration file that is specified in the TRANSFORM parameter, above. MAX_LINE_LENGTH Optional. An integer that specifies the maximum length of a line in the XML transformation data passed to gpload. FORMAT Optional. Specifies the format of the source data file(s) - either plain text (TEXT) or comma separated values (CSV) format. Defaults to TEXT if not specified. For more information about the format of the source data, see . DELIMITER Optional. Specifies a single ASCII character that separates columns within each row (line) of data. The default is a tab character in TEXT mode, a comma in CSV mode. You can also specify a non- printable ASCII character or a non-printable unicode character, for example: "\x1B" or "\u001B". The escape string syntax, E'character-code', is also supported for non-printable characters. The ASCII or unicode character must be enclosed in single quotes. For example: E'\x1B' or E'\u001B'. ESCAPE Specifies the single character that is used for C escape sequences (such as \n, \t, \100, and so on) and for escaping data characters that might otherwise be taken as row or column delimiters. Make sure to choose an escape character that is not used anywhere in your actual column data. The default escape character is a \ (backslash) for text-formatted files and a " (double quote) for csv-formatted files, however it is possible to specify another character to represent an escape. It is also possible to disable escaping in text-formatted files by specifying the value 'OFF' as the escape value. This is very useful for data such as text-formatted web log data that has many embedded backslashes that are not intended to be escapes. NULL_AS Optional. Specifies the string that represents a null value. The default is \N (backslash-N) in TEXT mode, and an empty value with no quotations in CSV mode. You might prefer an empty string even in TEXT mode for cases where you do not want to distinguish nulls from empty strings. Any source data item that matches this string will be considered a null value. FILL_MISSING_FIELDS Optional. The default value is false. When reading a row of data that has missing trailing field values (the row of data has missing data fields at the end of a line or row), Greenplum Database returns an error. If the value is true, when reading a row of data that has missing trailing field values, the values are set to NULL. Blank rows, fields with a NOT NULL constraint, and trailing delimiters on a line will still report an error. See the FILL MISSING FIELDS clause of the command. FORCE_NOT_NULL Optional. In CSV mode, processes each specified column as though it were quoted and hence not a NULL value. For the default null string in CSV mode (nothing between two delimiters), this causes missing values to be evaluated as zero-length strings. QUOTE Required when FORMAT is CSV. Specifies the quotation character for CSV mode. The default is double-quote ("). HEADER Optional. Specifies that the first line in the data file(s) is a header row (contains the names of the columns) and should not be included as data to be loaded. If using multiple data source files, all files must have a header row. The default is to assume that the input files do not have a header row. ENCODING Optional. Character set encoding of the source data. Specify a string constant (such as 'SQL_ASCII'), an integer encoding number, or 'DEFAULT' to use the default client encoding. If not specified, the default client encoding is used. For information about supported character sets, see the Greenplum Database Reference Guide. If you change the ENCODING value in an existing gpload control file, you must manually drop any external tables that were creating using the previous ENCODING configuration. gpload does not drop and recreate external tables to use the new ENCODING if REUSE_TABLES is set to true. ERROR_LIMIT Optional. Enables single row error isolation mode for this load operation. When enabled, input rows that have format errors will be discarded provided that the error limit count is not reached on any Greenplum Database segment instance during input processing. If the error limit is not reached, all good rows will be loaded and any error rows will either be discarded or captured as part of error log information. The default is to abort the load operation on the first error encountered. Note that single row error isolation only applies to data rows with format errors; for example, extra or missing attributes, attributes of a wrong data type, or invalid client encoding sequences. Constraint errors, such as primary key violations, will still cause the load operation to abort if encountered. For information about handling load errors, see . LOG_ERRORS Optional when ERROR_LIMIT is declared. Value is either true or false. The default value is false. If the value is true, rows with formatting errors are logged internally when running in single row error isolation mode. You can examine formatting errors with the Greenplum Database built-in SQL function gp_read_error_log('table_name'). If formatting errors are detected when loading data, gpload generates a warning message with the name of the table that contains the error information similar to this message. timestamp|WARN|1 bad row, please use GPDB built-in function gp_read_error_log('table-name') to access the detailed error row If LOG_ERRORS: true is specified, REUSE_TABLES: true must be specified to retain the formatting errors in Greenplum Database error logs. If REUSE_TABLES: true is not specified, the error information is deleted after the gpload operation. Only summary information about formatting errors is returned. You can delete the formatting errors from the error logs with the Greenplum Database function gp_truncate_error_log(). When gpfdist reads data and encounters a data formatting error, the error message includes a row number indicating the location of the formatting error. gpfdist attempts to capture the row that contains the error. However, gpfdist might not capture the exact row for some formatting errors. For more information about handling load errors, see "Loading and Unloading Data" in the Greenplum Database Administrator Guide. For information about the gp_read_error_log() function, see the command. EXTERNAL Optional. Defines the schema of the external table database objects created by gpload. The default is to use the Greenplum Database search_path. SCHEMA Required when EXTERNAL is declared. The name of the schema of the external table. If the schema does not exist, an error is returned. If % (percent character) is specified, the schema of the table name specified by TABLE in the OUTPUT section is used. If the table name does not specify a schema, the default schema is used. OUTPUT Required. Defines the target table and final data column values that are to be loaded into the database. TABLE Required. The name of the target table to load into. MODE Optional. Defaults to INSERT if not specified. There are three available load modes: - Loads data into the target table using the following method: INSERT INTO target_table SELECT * FROM input_data; - Updates the UPDATE_COLUMNS of the target table where the rows have MATCH_COLUMNS attribute values equal to those of the input data, and the optional UPDATE_CONDITION is true. UPDATE is not supported if the target table column name is a reserved keyword, has capital letters, or includes any character that requires quotes (" ") to identify the column. - Inserts new rows and updates the UPDATE_COLUMNS of existing rows where FOOBAR attribute values are equal to those of the input data, and the optional MATCH_COLUMNS is true. New rows are identified when the MATCH_COLUMNS value in the source data does not have a corresponding value in the existing data of the target table. In those cases, the entire row from the source file is inserted, not only the MATCH and UPDATE columns. If there are multiple new MATCH_COLUMNS values that are the same, only one new row for that value will be inserted. Use UPDATE_CONDITION to filter out the rows to discard. MERGE is not supported if the target table column name is a reserved keyword, has capital letters, or includes any character that requires quotes (" ") to identify the column. MATCH_COLUMNS Required if MODE is UPDATE or MERGE. Specifies the column(s) to use as the join condition for the update. The attribute value in the specified target column(s) must be equal to that of the corresponding source data column(s) in order for the row to be updated in the target table. UPDATE_COLUMNS Required if MODE is UPDATE or MERGE. Specifies the column(s) to update for the rows that meet the MATCH_COLUMNS criteria and the optional UPDATE_CONDITION. UPDATE_CONDITION Optional. Specifies a Boolean condition (similar to what you would declare in a WHERE clause) that must be met in order for a row in the target table to be updated (or inserted in the case of a MERGE). MAPPING Optional. If a mapping is specified, it overrides the default source-to-target column mapping. The default source-to-target mapping is based on a match of column names as defined in the source COLUMNS section and the column names of the target TABLE. A mapping is specified as either: target_column_name: source_column_name or target_column_name: 'expression' Where expression is any expression that you would specify in the SELECT list of a query, such as a constant value, a column reference, an operator invocation, a function call, and so on. PRELOAD Optional. Specifies operations to run prior to the load operation. Right now the only preload operation is TRUNCATE. TRUNCATE Optional. If set to true, gpload will remove all rows in the target table prior to loading it. Default is false. REUSE_TABLES Optional. If set to true, gpload will not drop the external table objects and staging table objects it creates. These objects will be reused for future load operations that use the same load specifications. This improves performance of trickle loads (ongoing small loads to the same target table). If LOG_ERRORS: true is specified, REUSE_TABLES: true must be specified to retain the formatting errors in Greenplum Database error logs. If REUSE_TABLES: true is not specified, formatting error information is deleted after the gpload operation. If the external_table_name exists, the utility uses the existing table. The utility returns an error if the table schema does not match the OUTPUT table schema. STAGING_TABLE Optional. Specify the name of the temporary external table that is created during a gpload operation. The external table is used by gpfdist. REUSE_TABLES: true must also specified. If REUSE_TABLES is false or not specified, STAGING_TABLE is ignored. By default, gpload creates a temporary external table with a randomly generated name. If external_table_name contains a period (.), gpload returns an error. If the table exists, the utility uses the table. The utility returns an error if the existing table schema does not match the OUTPUT table schema. The utility uses the value of SCHEMA in the EXTERNAL section as the schema for external_table_name. If the SCHEMA value is %, the schema for external_table_name is the same as the schema of the target table, the schema of TABLE in the OUTPUT section. If SCHEMA is not set, the utility searches for the table (using the schemas in the database search_path). If the table is not found, external_table_name is created in the default PUBLIC schema. FAST_MATCH Optional. If set to true, gpload only searches the database for matching external table objects when reusing external tables. The utility does not check the external table column names and column types in the catalog table pg_attribute to ensure that the table can be used for a gpload operation. Set the value to true to improve gpload performance when reusing external table objects and the database catalog table pg_attribute contains a large number of rows. The utility returns an error and quits if the column definitions are not compatible. The default value is false, the utility checks the external table definition column names and column types. REUSE_TABLES: true must also specified. If REUSE_TABLES is false or not specified and FAST_MATCH: true is specified, gpload returns a warning message. SQL Optional. Defines SQL commands to run before and/or after the load operation. You can specify multiple BEFORE and/or AFTER commands. List commands in the order of desired execution. BEFORE Optional. An SQL command to run before the load operation starts. Enclose commands in quotes. AFTER Optional. An SQL command to run after the load operation completes. Enclose commands in quotes.