Data Pipelines
Data pipelines enable you to load data from your chosen source into the Ocient Hyperscale Data Warehouse™. You can preview a data pipeline using the PREVIEW PIPELINE SQL statement to test the creation statement and any required data transformation. Then, you can create a data pipeline using the CREATE PIPELINE statement. To manage the load, use the START PIPELINE statement to start the load and the STOP PIPELINE statement to stop it. You can rename a data pipeline using the ALTER PIPELINE RENAME statement. To see the full definition of a created pipeline, use the EXPORT PIPELINE statement. When you finish with the load, you can use the DROP PIPELINE statement to remove the data pipeline. You can create user-defined data pipeline functions using the CREATE PIPELINE FUNCTION statement and remove the function using the DROP PIPELINE FUNCTION statement. Also, you can administer privileges for data pipelines and data pipeline functions. For details, see Data Control Language (DCL) Statement Reference.
CREATE PIPELINE
CREATE PIPELINE defines a data pipeline that you can execute with the START PIPELINE SQL statement. Specify the type of load, data source, and data format.
You must have the ALTER privilege on the pipeline. For details, see Data Control Language (DCL) Statement Reference.
Syntax
Pipeline Identity and Naming
The name of a data pipeline is unique in an Ocient® System. Reference the pipeline in other SQL statements like START PIPELINE, STOP PIPELINE, and DROP PIPELINE using the name of the pipeline. The SQL statement throws an error if a pipeline with the same name already exists unless you specify the IF NOT EXISTS option. You can rename a pipeline with the ALTER PIPELINE SQL statement.
Update a Pipeline
You can update a pipeline with the OR REPLACE clause in the CREATE PIPELINE SQL statement. Use this clause when you want to continue loading from the current place in a continuous load, but you need to modify transformations or other settings. If you specify the OR REPLACE clause and the pipeline already exists, the database replaces the original pipeline object with the options specified in the new CREATE OR REPLACE PIPELINE statement. When you replace an existing pipeline, the pipeline retains its current position in the source data so that data is not duplicated when the pipeline is resumed with a START PIPELINE SQL statement. First, you must stop a pipeline before executing the CREATE OR REPLACE SQL statement.
Data Pipeline Modes
You can define pipelines in either batch BATCH, continuous CONTINUOUS, or transactional TRANSACTIONAL mode.
- File sources (e.g.,
s3,filesystem) supportBATCHandCONTINUOUSmodes. File-based loads default toBATCHmode if you do not specify this keyword. - Apache® Kafka® only supports
CONTINUOUSmode. Loads with a Kafka source default toCONTINUOUSmode if you do not specify this keyword. - When you execute the
START PIPELINESQL statement using a data pipeline in theBATCHmode, the system creates a static list of files with thePENDINGstatus in thesys.pipeline_filessystem catalog table. With theCONTINUOUSmode, the monitor appends new incoming files to the list of files in thesys.pipeline_filessystem catalog table. - With the
CONTINUOUSmode, you can apply filters for the data pipeline. The system only uses files in the consumed messages if the filenames match the filters. For this mode, these options are invalid:- PREFIX
- SORT_BY
- SORT_DIRECTION
- SORT_REWRITE
- START_CREATED_TIMESTAMP
- END_CREATED_TIMESTAMP
- START_MODIFIED_TIMESTAMP
- END_MODIFIED_TIMESTAMP
- The
TRANSACTIONALmode enables the data pipeline to roll back the interim results of the load if an error occurs during load execution. The system makes all data visible only after the load completes successfully. This mode supports all options that theBATCHmode does.
Required Options
You must define certain options in every pipeline. For these options, there is no default value. Optional options need to be present only if you use specific functions. A pipeline must contain the SOURCE, EXTRACT FORMAT, and INTO table_name ... SELECT statements.
These options depend on each other: IF NOT EXISTS and OR REPLACE SQL statements are mutually exclusive.
SELECT Statement and Data Transformation
Use the INTO table_name ... SELECT SQL statement in the CREATE PIPELINE SQL statement to specify how to transform the data. The SELECT statement includes a set of one or more expressions and a target column name in the form expression as column_name. The expression part in the statement contains a source field reference (e.g., $1 or $my_field.subfield) and, optionally, the transformation function you want to apply.
If your data is nested in arrays, you can use special transformation functions, such as the EXPLODE_OUTER function, to expand the data into individual rows.
For details about data transformation and supported transformation functions, see Transform Data in Data Pipelines.
For details about data types and casting, see Data Types for Data Pipelines and Data Formats for Data Pipelines.
You can also specify metadata values, such as filename, to load in the SELECT SQL statement. For details, see Load Metadata and File-Based Partitioned Data in Data Pipelines.
This is an example of a transformation statement snippet.
Optionally, you can filter the load by using the WHERE clause in the form WHERE filter_expression. This expression should evaluate to a Boolean value or NULL and can include more than one filter expression. The system loads rows that contain data matching the filter criteria when the expression evaluates to true. The system does not load the rows when the expression evaluates to false or NULL. You can include any transform in the WHERE clause as in the SELECT clause.
This is an example of a filter snippet that loads order data for customers whose last name starts with the letter a. Use the COALESCE function to return only non-NULL values.
NULL and Default Value Handling
The Ocient System has specific ways to handle NULL and default values in the data pipeline. Consider this information when you prepare data to load and write the CREATE TABLE and CREATE PIPELINE SQL statements.
To load NULL values, insert the NULL value in the data. In this case, if you specify NOT NULL for the target column in the CREATE TABLE statement, the data pipeline fails to load.
If you omit a column in the SELECT SQL statement, the data pipeline loads the default value for the column. If you do not specify the default value, the pipeline loads a NULL value. If you specify NOT NULL for the target column, the data pipeline also fails to load.
You can use the DEFAULT keyword to load a default value. In this case, if the column does not have a default value, the pipeline fails to load. If the pipeline loads a NULL into a column with a specified default value, you can use COALESCE(\<value>, DEFAULT) to insert the default value instead of the NULL value, where \<value> is the NULL column. You can modify the load of one column at a time in this way.
This table describes the data pipeline behavior for NULL or omitted column values.
Required Privileges
You must have the CREATE PIPELINE privilege on the underlying database and the VIEW privilege on each table in the pipeline definition to execute the CREATE PIPELINE SQL statement. The table must already exist.
See the START PIPELINE SQL statement for the required privileges to execute a pipeline.
For details, see Data Control Language (DCL) Statement Reference.
Examples
Load JSON Data from Kafka
This example loads JSON data from Kafka using the CREATE PIPELINE SQL statement. Use the bootstrap server 192.168.0.1:9092 using the Kafka topic orders. Load data into the public.orders table. Specify the data to load as these JSON selectors:
- Identifier
$id - User identifier
$user_id - Product identifier
$product_id - Subtotal amount
$subtotal - Tax
$tax - Total amount
$total - Discount amount
$discount - Created time
$created_at - Quantity
$quantity
For a complete tutorial, see Data Pipeline Load of JSON Data from Kafka.
Load Delimited Data from S3
This example loads delimited data in CSV format from Amazon® Web Services℠ (AWS℠) S3. Use the https://s3.us-east-1.amazonaws.com endpoint with the ocient-examples bucket and path metabase_samples/csv/orders.csv. Denote path-style access using the ENABLE_PATH_STYLE_ACCESS option set to true. Specify one header line with the NUM_HEADER_LINES option. Load data into the public.orders table. Specify the data to load using the column numbers:
- Idenfier
- User identifier
- Product identifier
- Subtotal amount
- Tax
- Total amount
- Discount amount
- Created time
- Quantity
For a complete tutorial, see Data Pipeline Load of CSV Data from S3.
Continuous File Load of Delimited Data in CSV Files
Create a data pipeline that uses continuous file loading with delimited data in CSV files. Specify to use 32 partitions and 16 cores with the PARTITIONS and CORES options, respectively. The source is S3 with the http://endpoint.ocient.com endpoint and cs_data bucket. Specify the filter '*.csv' to find all files with a filename that matches a glob pattern without subdirectories, for example, data.csv. The system filters filenames with subdirectories such as data/data_sample.csv.
For continuous file loading, specify the MONITOR option to use the Kafka monitor. Specify the test-broker:9092 bootstrap server, cfl_kafka_ten_adtech_flat_small Kafka topic, and reset the offset to the smallest offset using the earliest value of the AUTO_OFFSET_RESET option. Set the client group identifier to 84079bf1-bdc4-4b10-ba12-41ba6b17dffe.
The format is csv with the record delimiter as the newline character \n. Load data in the public.ad_sessions table.
The SELECT statement identifies the columns to load by number. There are 39 fields in the CSV data. For each column, transform each column using cast functions. For details, see Scalar Data Conversion Functions for each function. See Date and Time Functions for the TO_TIMESTAMP function.
Transactional Load of Delimited Data in CSV Files
Create a data pipeline that uses transactional file loading with delimited data in CSV files. The source is S3 with the http://endpoint.ocient.com endpoint and cs_data bucket. Specify the filter '*.csv' to find all files with a filename that matches a glob pattern without subdirectories, for example, data.csv. The system filters filenames with subdirectories such as data/data_sample.csv.
The format is csv. Load data in the public.ad_sessions table.
The SELECT statement identifies the columns to load by number. For each column, transform each column using cast functions. For details, see Scalar Data Conversion Functions for each function. See Date and Time Functions for the TO_TIMESTAMP function.
SOURCE Options
File-Based Source Options
Options that apply to both the S3, FILESYSTEM, and HDFS sources.
*indicates unlimited wildcard characters except for the path character,/.**indicates wildcard characters, including path separators.?indicates a single wildcard character.
FILTER_REGEX— Regular expression patterns to filter files. Some common patterns include:.matches any character.*matches any 0 or more of the preceding character.+matches a single character.[135]matches any one character in the set.[1-5]matches any one character in the range.(a\|b)matches a or b.
ℹ️ When you use the FILTER or FILTER_GLOB options with a continuous data pipeline, the system supports only basic globbing, and extended, range globbing is not supported.
FILTER_GLOB Examples:
List all CSV files in subdirectories named2024that are in any subdirectory of thetradesdirectory, which is in the root of the bucket.FILTER_GLOB = '/trades/*/2024/*.csv'
List all CSV files in the bucket in all subdirectories.FILTER_GLOB = '**/*.csv'
FILTER_REGEX Examples:
List alljson.gzfiles in the bucket that contain the nameordersanywhere in the path.FILTER_REGEX = '.*orders.*\.json\.gz'
List all files in the bucket in the root pathmetricsorvalueswhere the date string on the filename is 2000 to 2004.FILTER_REGEX = '/(metrics\|values)/.*200[0-4].*'| | PREFIX |NULL| STRING
or
ARRAY OF STRINGS | Optional.
Specify a prefix within which to apply the filter. When you specify a list of prefixes, the system applies the filter to each one, and the results are unioned together.
Prefixes must be paths to directories, meaning they end with a forward slash. ForFILESYSTEMsources, paths should be absolute, meaning they begin with a forward slash.
ForS3sources, use prefixes to reduce the search space when listing objects within the specifiedBUCKET. For maximum performance, use thePREFIXoption whenever possible, especially when combined with theFILTER_REGEXoption.
ℹ️This option is not available for continuous data pipelines.
Examples:
List all CSV files in the2024subdirectory offiles.PREFIX '/files/2024/' FILTER '**/*.csv'
List all JSON files of subdirectory2024/09/in theordersdirectory.PREFIX '/data/orders/2024/09/' FILTER_REGEX '.*/orders/.*json'
List all JSON files in multiple subdirectories.PREFIX ['/data/orders/2024/09/', '/data/orders/2024/10/']| | COMPRESSION_METHOD |NULL| STRING | Optional.
The method the Ocient System uses to decompress file data. The only supported option isgzip.
To load uncompressed data, omit the COMPRESSION_METHOD option.
ℹ️The COMPRESSION_METHOD option is only applicable to file-based sources. Kafka pipelines automatically decompress data based on the Kafka topic configuration. | | SORT_BY |filename| STRING | Optional.
The sort criteria for sorting the file list before the load. Supported options are:
*filename— Sort files lexicographically by the filename.
created— Sort files based on the file created timestamp.modified— Sort files based on the file modified timestamp.
Sorting files such that the Ocient System sorts the data within the files according to the TimeKey® column in the target table can lead to better query performance.
ℹ️This option is not available for continuous data pipelines. | | SORT_DIRECTION |ASC| STRING | Optional.
The sort direction, eitherASCascending orDESCdescending, determines the sort order. If you specify this option, you must also specify the SORT_BY option.
ℹ️This option is not available for continuous data pipelines. | | SORT_REWRITE |NULL| STRING | Optional.
This option is a sort comparator, allowing files to be renamed during the sort operation using capture groups from the filter regular expression. If you specify this option, you must also specify theFILTER_REGEXoption.
If you do not specify this option, the system uses the sorting specified by the SORT_BY option.
ℹ️This option is not available for continuous data pipelines.
Example:FILTER_REGEX '(\d+)_(\d+)_(\d+)-order.json'SORT_REWRITE '\3-\1-\2.json'
“
This specification renames the file from5_6_1999-orders.jsonto1999_5_6.jsonby switching the order of the date fields. | | START_FILENAME |NULL| STRING | Optional.
The filename string that is the lower bound to filter for files lexicographically for batch pipelines. (inclusive)
Use the full path of the file, such as'/dir/load_file.json'. If the file is located in the top-most directory, start the path with a slash/, such as'/load_file.json'.
You can use this option without the END_FILENAME option.
If you specify the END_FILENAME option, the value of the START_FILENAME option must be smaller than the value for the END_FILENAME option lexicographically. | | END_FILENAME |NULL| STRING | Optional.
The filename string that is the upper bound to filter for files lexicographically for batch pipelines. (inclusive)
Use the full path of the file, such as'/dir/load_file.json'. If the file is located in the top-most directory, start the path with a slash/, such as'/load_file.json'.
You can use this option without the START_FILENAME option.
If you specify the END_FILENAME option, the value of the START_FILENAME option must be smaller than the value for the END_FILENAME option lexicographically. | | START_CREATED_TIMESTAMP |NULL| TIMESTAMP-formatted STRING | Optional.
The ISO-8601-compliant date or date time that is used as the lower bound (inclusive) to filter files by created timestamp for batch pipelines. The time zone should match the file metadata.
If you specify both, the value for the START_CREATED_TIMESTAMP option must be before the value for the END_CREATED_TIMESTAMP option.
ℹ️This option is not available for continuous data pipelines. | | END_CREATED_TIMESTAMP |NULL| TIMESTAMP-formatted STRING | Optional.
The ISO-8601-compliant date or date time that is used as the lower bound (inclusive) to filter files by created timestamp for batch pipelines. The time zone should match the file metadata.
If you specify both, the value for the START_CREATED_TIMESTAMP option must be before the value for the END_CREATED_TIMESTAMP option.
ℹ️This option is not available for continuous data pipelines. | | START_MODIFIED_TIMESTAMP |NULL| TIMESTAMP-formatted STRING | Optional.
The ISO-8601-compliant date or date time that is used as the lower bound (inclusive) to filter files by modified timestamp for batch pipelines. The time zone should match the file metadata.
If you specify both, the value for the START_MODIFIED_TIMESTAMP option must be before the value for the END_MODIFIED_TIMESTAMP option.
ℹ️This option is not available for continuous data pipelines. | | END_MODIFIED_TIMESTAMP |NULL| TIMESTAMP-formatted STRING | Optional.
The ISO-8601-compliant date or date time that is used as the lower bound (inclusive) to filter files by modified timestamp for batch pipelines. The time zone should match the file metadata.
If you specify both, the value for the START_MODIFIED_TIMESTAMP option must be before the value for the END_MODIFIED_TIMESTAMP option.
ℹ️This option is not available for continuous data pipelines. |
S3 Source Options
You can apply these options to data sources of the SOURCE S3 type, which include S3 and S3-compatible services.
S3 Credentials Hierarchy
The S3 source configuration supports this hierarchy to obtain S3 credentials:
- Level 1: Data pipeline configuration (set by using the
ACCESS_KEY_IDandSECRET_ACCESS_KEYoptions) - Level 2: AWS SDK Default Credential Provider Chain(set by using the instructions provided in the web page)
- Level 3: Anonymous access (set by default)
If the Ocient System does not obtain the credentials at a level, the system tries a lower level.
You can choose the level to store the credentials, where Level 1 is the highest. Higher levels take precedence for credential storage.
FILESYSTEM Source Options
No options exist specific to the file system source (SOURCE FILESYSTEM) except for general file-based source options.
When you load data using SOURCE FILESYSTEM, the files must be addressable from all of your Loader Nodes. The Ocient System uses the specified path in the pipeline PREFIX and FILTER options to select the files to load.
A shared view of the files you want to load must be available to all Loader Nodes involved in a pipeline. For example, you can use a Network File System (NFS) mount available to all Loader Nodes at a common path on each node.
Example
This example CREATE PIPELINE SQL statement snippet contains a FILESYSTEM source and filters to all CSV files in the /tmp/sample-data/ directory on each of the Loader Nodes.
HDFS Source Options
You can specify these options for Apache® Hadoop® Distributed File System (HDFS) data sources (SOURCE HDFS).
For advanced options, see Data Pipeline Load of JSON Data from HDFS.
KAFKA Source Options
You can apply these options to Kafka data sources (SOURCE KAFKA).
For compression, you do not need to specify a compression option in Kafka-based pipelines, because the Ocient System handles the compression type automatically. Records produced to the Kafka broker with a compression.type setting or with the compression.type set on the topic automatically decompress when the loading process consumes the records. The loading process uses built-in headers in Kafka to determine the required decompression during extraction.
For the consumer configuration, to create a secure connection from the Kafka consumer to a Kafka Broker, set the "security.protocol" key along with any SSL or SASL keys.
If a certificate file is required, you must add it to the truststore used by the JVM® on all Loader Nodes. The truststore path must be identical on all Loader Nodes. The Kafka configuration can reference this truststore path.
If you specify the ssl.certificate.location or ssl.ca.location consumer configuration, you must specify both of these configurations. Otherwise, the system throws an error. For example: CONFIG '{"auto.offset.reset": "earliest","ssl.certificate.location":"/etc/blab/file1.txt","ssl.ca.location":"/etc/blab/file2.txt"}'
Continuous File Loading Source Options
Specify these options for data pipelines that use FILESYSTEM or S3 sources with the CONTINUOUS mode. For a Kafka source, do not use these options.
General File Monitor Options
SQS Monitor Options
Use these options when you use MONITOR sqs for Amazon SQS.
Kafka Monitor Options
Use these options when you use MONITOR kafka for Kafka.
The same Kafka CONFIG option override considerations apply. For details, see KAFKA Source Options.
LOOKUP Options
You can optionally look up data in a table from an external database. You can include this table in the SELECT statement of the CREATE PIPELINE SQL statement and perform join operations on its columns. To use the LOOKUP keyword, specify the external source name lookup_source.
You can look up data in multiple external databases. In this case, use the LOOKUP keyword with the source name and corresponding options for each database.
You must provide the appropriate JDBC JAR file for the JDBC connection to external databases. For tables in the Ocient System, this JAR file is not needed.
The Ocient System executes the JDBC code as trusted code. Only provide trusted JAR files to the loading process. The streamloader.extractorEngineParameters.configurationOption.engine.external.jdbc.jarRootDirectory configuration parameter specifies the location of the JAR file. For details, see Configuration Settings for Data Pipelines.
EXTRACT Options
General Extract Options
You can specify these options on any of the allowed FORMAT types.
For ASN.1, Apache® Avro™, and Parquet extract options, the SCHEMA option is a MAP type with a NULL default value. This option is optionally specified depending on the format. SCHEMA specifies the syntax of options for schema retrieval.
ASN.1 Extract Options
You can specify these options for ASN.1 data record extraction (FORMAT ASN.1).
For details about ASN.1-formatted data, see Load ASN.1 Data.
Avro Extract Options
You can specify these options for Avro data record extraction. The SCHEMA options are all optional for object container files (OCF).
For Kafka loads, the schema configuration must include either the URL option or the INLINE option, but not both.
For file-based loads, the schema configuration can include:
- Either the
INLINEoption or theINFER_FROMoption, but not both of these options - Neither the
INLINEnor theINFER_FROMoptions
For details about loading Avro-formatted data, see Load Avro Data.
BINARY Extract Options
You can apply these options to binary data record extraction (FORMAT BINARY).
For details about BINARY-formatted data, see Load Binary Data.
The general option CHARSET_NAME has a different default value for FORMAT BINARY.
The Ocient System trims the default padding character of a space from the end of the text data in binary data.
Delimited and CSV Extract Options
You can specify these options for delimited and CSV format data record extraction (FORMAT DELIMITED or FORMAT CSV data formats, which are aliases).
For details about working with delimited and CSV data, see Load Delimited and CSV Data.
JSON Extract Options
No options exist for JSON data record extraction (FORMAT JSON).
For details about JSON-formatted data, see Load JSON Data.
PARQUET Extract Options
You can specify these options for Parquet data record extraction (FORMAT ``PARQUET).
For details about Parquet-formatted data, see Load Parquet Data.
When you use the FORMAT PARQUET option with an AWS S3 Source, the ENDPOINT option is required.
XML Extract Options
No options exist for the XML format extraction (FORMAT XML).
For details about XML-formatted data, see Load XML Data.
Bad Data Targets
Bad data represents records that the Ocient System could not load due to errors in the transformations or invalid data in the source records. You can provide options for a bad data target that the Ocient System uses during pipeline execution to capture the records that are not loaded. The original bytes that the pipeline tried to load are captured in the bad data target along with the metadata about the error, such as the error message or source.
Kafka is the only supported bad data target.
Kafka Bad Data Target
When you use Kafka as a bad data target, the Ocient System produces the original bytes of the source record into the Kafka topic of your choice. The Ocient System includes the metadata about the record in the header of the record as it is sent to Kafka. You can configure the Kafka topic on your Kafka Brokers using the retention and partition settings of your choice.
In the event that the Kafka Broker is unreachable when the Ocient System attempts to produce a bad data record to the bad data target, the system logs an error on the Loader Node, and the pipeline continues.
Example
This example CREATE PIPELINE SQL statement snippet contains a bad data target definition using the BAD_DATA_TARGET option.
Kafka Bad Data Target Options
Advanced Pipeline Tuning Options
You can use pipeline tuning options to control the parallelism or batching dynamics of your pipelines. This tuning can throttle the resources used on a pipeline or increase parallel processing across Loader Nodes. These options are advanced settings that might require a detailed understanding of the underlying mechanics of the loading infrastructure in the Ocient System to employ. Due to the inherent nature of each source type, the behavior of these options can differ between file-based and Kafka-based loads. All these options are optional.
DROP PIPELINE
DROP PIPELINE removes an existing pipeline in the current database. You cannot remove a pipeline that is running.
You must have the DROP privilege on the pipeline to execute this SQL statement. For details, see Data Control Language (DCL) Statement Reference.
When you drop a pipeline, the Ocient System also removes the associated system catalog information, such as pipeline errors, events, files, partitions, and metrics.
Syntax
Examples
Remove Existing Data Pipeline
Remove an existing pipeline named ad_data_pipeline.
Remove Existing Data Pipeline by Checking for Existence
Remove an existing pipeline named ad_data_pipeline or return a warning if the Ocient System does not find the pipeline in the database.
PREVIEW PIPELINE
PREVIEW PIPELINE enables you to view the results of loading data for a specific CREATE PIPELINE SQL statement without creating a whole data pipeline and without storing those results in the target table. Using this SQL statement, you can iterate quickly and modify the syntax as needed to achieve your expected results. After you confirm your expected results, you can use the same syntax in the body of the CREATE PIPELINE statement with the appropriate source.
A table must exist in the database to serve as the target of your PREVIEW PIPELINE statement. This table ensures the pipeline matches the column types of the target table. However, the execution of this statement does not load data into the target table.
Preview Sources
The SOURCE INLINE source type is available only for the PREVIEW PIPELINE SQL statement. You cannot create a data pipeline with inline source data.
Other source types defined in the CREATE PIPELINE statement, S3, KAFKA, and FILESYSTEM, are compatible with the PREVIEW PIPELINE statement. The extract options vary by the source type to mirror the CREATE PIPELINE statement. The database returns 10 records by default.
Preview Error Handling
Pipeline-level errors cause the PREVIEW PIPELINE SQL statement to fail. The Ocient System returns an error and no result set. However, the Ocient System accumulates record-level errors that occur during the execution of this statement in a single warning that the system returns along with the result set. Each line of the warning describes a record-level error in human-readable form or as a JSON blob, depending on the value of the SHOW_ERRORS_AS_JSON option. Rows or columns that encounter record-level errors have NULL values in the result set.
Preview Limitations
Limitations of this SQL statement are:
- Before executing a
PREVIEW PIPELINESQL statement, you must create a table for the Ocient System to have context for the preview. - The
COLUMN_DEFAULT_IF_NULLoption from theCREATE PIPELINESQL statement has no effect on thePREVIEW PIPELINESQL statement. - The
PREVIEW PIPELINESQL statement does not honor the assignment of a service class based on text matching. - These source options are not supported:
START_FILENAMEEND_FILENAME
- When you execute two duplicate
PREVIEW PIPELINEstatements for a specific Kafka topic, the two statements share a consumer group. If the topic is small, one or both of the result sets might only be a partial result. - For multiple tables, you can preview only one table at a time. You must specify the name of the table you want to preview using the
FORkeyword. - The preview of a continuous data pipeline for loading data from files is not supported.
Syntax
Though this syntax shows the CSV format, you can also use the PREVIEW PIPELINE statement with the other formats.
SQL Statement Options
You must specify at least one column name in the SELECT part of the syntax. The name of the specified column must match the name of the column in the created table. The number of columns in the SELECT part can be less than those in the created table.
For definitions of other extract options, see the CREATE PIPELINE SQL statement options in CREATE PIPELINE.
Examples
Preview Pipeline Using CSV Format
Preview the load of two rows of data. First, create a table to serve as the context for the load. The previewload table contains three columns with these data types: string, integer, and Boolean.
Create the preview pipeline testpipeline with this data: 'hello,2,true|bye,3,false'. Specify the CSV extract format, | record delimiter, and the , field delimiter. Load the data without transformation.
Output
Delete the previewload table.
Preview Pipeline Using CSV Format with Escape Characters
Preview the load of two rows of data. First, create a table to serve as the context for the load. The previewload table contains three columns with these data types: string, integer, and Boolean.
Create the preview pipeline testpipeline with this data: 'hello\tworld,2,true|bye\tworld,3,false'. Specify the CSV extract format, | record delimiter, and , field delimiter. Load the data without transformation. In this case, the data contains the special character \t. You must escape the character by using the escape sequence e.
Output
Delete the previewload table.
Preview Pipeline Using CSV Format with Transformation
Create a table to serve as the context for the load. The previewload table contains three string columns.
Create the preview pipeline testpipeline with this data: 'hello,world|bye,world'. Specify the CSV extract format, | record delimiter, and the , field delimiter. Load the data with a transformation to concatenate the two strings and return the result in the third column.
Output
The third column contains the concatenated result of the first two columns.
Delete the previewload table.
Preview Pipeline Using the Kafka Source
Create the previewload table with these columns:
id— Non-NULL integersalut— Non-NULL stringname— Non-NULL stringsurname— Non-NULL stringzipcode— Non-NULL integerage— Non-NULL integerrank— Non-NULL integer
Create the preview pipeline test_small_kafka_simple_csv. Specify the ddl_csv topic. Indicate that the Kafka consumer should not write its durably-made record offsets to the Kafka Broker by using the WRITE_OFFSETS option set to false. Specify the bootstrap server as servername:0000 and configuration options as "auto.offset.reset": "earliest" by using the BOOTSTRAP_SERVERS and CONFIG options, respectively. Limit the returned results to three rows by using the LIMIT option. Specify the CSV extract format and \n record delimiter by using the FORMAT and RECORD_DELIMITER extract options, respectively.
START PIPELINE
START PIPELINE begins the execution of the specified data pipeline that extracts data and loads it into the target tables specified by the CREATE PIPELINE SQL statement.
When you execute the START PIPELINE SQL statement, the Ocient System creates a static list of files in the sys.pipeline_files system catalog table and marks them with the PENDING status. After the system assigns a file to an underlying task, the system marks the file as QUEUED. After the system verifies that the file exists, the system marks the file as LOADING to signify that a Loader Node has started reading the source data. Finally, upon successfully loading the file, the system transitions the status of the file to the terminal status LOADED.
A Kafka pipeline never enters the COMPLETED state in the information_schema.pipeline_status view. Instead, the pipeline remains running after you start the pipeline until you stop it or the pipeline reaches the specified error limit using the ERROR LIMIT option.
You must have the EXECUTE privilege on the pipeline and the INSERT privilege on any table that is a target in the pipeline. For details, see Data Control Language (DCL) Statement Reference.
Syntax
SQL Statement Options
For the query to execute successfully, the specified node names must identify nodes that have:
ACTIVEoperational statusstreamloaderrole
When you execute the START PIPELINE SQL statement, the Ocient System creates a static list of files only for batch pipelines and a dynamic list for continuous pipelines in the sys.pipeline_files system catalog table.
Examples
Start an existing pipeline named ad_data_pipeline with default settings.
Start an existing pipeline named ad_data_pipeline with error tolerance (tolerate 10 errors before aborting the pipeline). For details about error tolerance, see Error Tolerance in Data Pipelines.
Data pipelines log a message for each pipeline error to the sys.pipeline_errors system catalog table, even if you do not specify the ERROR option. Use BAD_DATA_TARGET settings to capture the original source data.
Start an existing pipeline named ad_data_pipeline using the Loader Node named stream-loader1.
To resume a pipeline with file loading, see Data Pipeline Behavior Considerations.
To restart a Kafka data pipeline, see Data Pipeline Behavior Considerations.
For pipeline dependencies, see Data Pipeline Behavior Considerations.
STOP PIPELINE
STOP PIPELINE stops the execution of the pipeline and its associated tasks. After you stop a pipeline, you can execute the START PIPELINE SQL statement on the pipeline to run the pipeline again. Regardless, the load deduplicates any records previously loaded in the same pipeline.
You must have the EXECUTE privilege on the pipeline to execute this SQL statement. For details, see Data Control Language (DCL) Statement Reference.
Syntax
Example
Stop an existing pipeline named ad_data_pipeline.
You can see the status of the parent tasks in the sys.tasks system catalog table and see the status of the child tasks in the sys.subtasks system catalog table.
ALTER PIPELINE RENAME
ALTER PIPELINE RENAME TO SQL statement changes the name of the pipeline object, while retaining its identifier, options, and other metadata. The Ocient System reflects this change in the sys.pipelines system catalog table. Then, you must use the new name when you refer to the pipeline in SQL statements.
You must have the ALTER privilege on the pipeline to execute this SQL statement. For details, see Data Control Language (DCL) Statement Reference.
Syntax
Example
Rename an existing pipeline named ad_data_pipeline to renamed_pipeline.
EXPORTPIPELINE
EXPORT PIPELINE returns the CREATE PIPELINE SQL statement used to create the pipeline object. You can use the output of this statement to recreate an identical pipeline when you remove the original pipeline.
The execution of this statement censors sensitive S3 values like ACCESS_KEY_ID and SECRET_ACCESS_KEY and Kafka Consumer Configuration password-type fields. The database replaces them with *****.
To execute this statement, you must have the VIEW privilege on the pipeline and any table the pipeline targets. For details, see Data Control Language (DCL) Statement Reference.
Syntax
Example
Export an existing pipeline in the database ad_data_pipeline.
CREATE PIPELINE FUNCTION
CREATE PIPELINE FUNCTION enables you to define a function for loading data. Define the function behavior using the Apache® Groovy™ language. For details bout this language, see The Apache Groovy Programming Language.
Function arguments and output are strongly typed and immutable.
You can test the execution of your function using the PREVIEW PIPELINE SQL statement.
The Ocient System does not support the overload of function names.
Syntax
Install and Enable Third-Party Libraries
You can use the default list of supported third-party libraries or additional third-party libraries that you install.
Supported Libraries
Data pipeline functions can import classes from the default list of supported third-party libraries. This table provides the resources for each supported library package.
Additional Libraries
You can install and enable additional third-party libraries to import for use in your data pipeline functions.
You must install the JAR package on all Loader Nodes in the /opt/ocient/current/lib/extractorengine_udt folder.
Then, add the fully qualified class name in the function import list as part of the library_name parameter. For example, to reference the ByteBuffer class from the com.fastbuffer package, specify com.fastbuffer.ByteBuffer in the library_name parameter and use the class in the Groovy definition as var x = new com.fastbuffer.ByteBuffer().
Groovy Data Type Mapping
For the Groovy definition, the Ocient System maps its SQL data type to the corresponding Groovy data type. Your Groovy code should use the Groovy data type defined in this table for any input arguments and output.
Example
Create the sort_function data pipeline function to sort an array of integers. The function has two input arguments: value, a non-NULL array of integers, and ascending, the sort order. The function returns a non-NULL array of integers. If value is empty, the function throws an error.
The function imports these Java libraries:
java.lang.Integerjava.util.ArrayListjava.util.Collectionsjava.util.Comparatorjava.util.List
Define the Groovy code. Because the input arguments do not change, the example Groovy code first copies the value argument, sorts the copied list according to the sort order, and returns the sorted array.
View the creation information about the sort_function function using the sys.pipeline_functions system catalog table. This statement returns the function name, return type, argument names, data types of the arguments, and the list of imported libraries.
DROP PIPELINE FUNCTION
DROP PIPELINE FUNCTION removes an existing pipeline function.
You must have the DROP privilege on the pipeline function to execute this SQL statement. For details, see Data Control Language (DCL) Statement Reference.
Syntax
Examples
Remove the Existing Pipeline Function
Remove an existing pipeline function named sort_function.
Remove an Existing Pipeline Function by Checking for Existence
Remove an existing pipeline function named sort_function or return a warning if the Ocient System does not find the function in the database.
Related Links
Data Pipeline Load of CSV Data from S3
Data Pipeline Load of Parquet Data from S3
Transform Data in Data Pipelines
Data Pipeline Behavior Considerations
Load Metadata and File-Based Partitioned Data in Data Pipelines

