ORC Writer

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Snap type:

Write

Description:

This Snap converts documents into the ORC format and writes the data to HDFS, S3, or the local file system.

  • Expected upstream Snaps: Any Snap with a document output view.
  • Expected downstream Snaps: [None]
  • Expected input: A document.
  • Expected output: [None]
Prerequisites:

[None]

Support and limitations:

All expression Snap properties (when '=' button is pressed) can be evaluated from pipeline parameters only, not from input documents. Input documents are data to be formatted and written to the target files.

Account: 

The ORC Writer works with the following accounts:

Views:
InputThis Snap has exactly one document input view. 
Output

This Snap has at most one document output view.

ErrorThis Snap has at most one document error view and produces zero or more documents in the view.

Settings

Label

Required. The name for the Snap. You can modify this to be more specific, especially if you have more than one of the same Snap in your pipeline.

Default Value: ORC Writer

Directory



Required. The path to a directory from which you want the ORC Reader Snap to read data. All files within the directory must be ORC formatted.

Basic directory URI structure

  • HDFS: hdfs://<hostname>:<port>/
  • S3: s3:///<S3 bucket name>/<file-path>
  • ABFS(S): abfs(s):///filesystem/<path>/
  • ABFS(S): abfs(s)://filesystem@accountname.endpoint/<path>

The Directory property is not used in the pipeline execution or preview, and used only in the Suggest operation. When you press the Suggest icon, the Snap displays a list of subdirectories under the given directory. It generates the list by applying the value of the Filter property.

Example

  • hdfs://ec2-54-198-212-134.compute-1.amazonaws.com:8020/user/john/input/

  • webhdfs://cdh-qa-2.fullsail.Snaplogic.com:50070/user/ec2-user/csv/
  • s3://test-s3-drea/8867_output.json
  • _dirname 

  • file:///home/snaplogic/file.orc
  • abfs:///filesystem2/dir1
  • abfs://filesystem2@snaplogicaccount.dfs.core.windows.net/dir1

Default valuehdfs://<hostname>:<port>/


Filter


Use glob patterns to display a list of directories or files when you click the Suggest icon in the Directory or File property. A complete glob pattern is formed by combining the value of the Directory property with the Filter property. If the value of the Directory property does not end with "/", the Snap appends one, so that the value of the Filter property is applied to the directory specified by the Directory property.

Default Value: *

For more information on glob patterns, click the link below.


 Glob Pattern Interpretation Rules

Glob Pattern Interpretation Rules

The following rules are used to interpret glob patterns:

  • The * character matches zero or more characters of a name component without crossing directory boundaries. For example, the *.csv pattern matches a path that represents a file name ending in .csv, and *.* matches all file names that contain a period.

  • The ** characters match zero or more characters across directories; therefore, it matches all files or directories in the current directory and in its subdirectories. For example, /home/** matches all files and directories in the /home/ directory.

  • The ? character matches exactly one character of a name component. For example, 'foo.?' matches file names that start with 'foo.' and are followed by a single-character extension.

  • The \ character is used to escape characters that would otherwise be interpreted as special characters. The expression \\ matches a single backslash, and \{ matches a left brace, for example.

  • The ! character is used to exclude matching files from the output. 
  • The [ ] characters form a bracket expression that matches a single character of a name component out of a set of characters. For example, '[abc]' matches 'a', 'b', or 'c'. The hyphen (-) may be used to specify a range, so '[a-z]' specifies a range that matches from 'a' to 'z' (inclusive). These forms can be mixed, so '[abce-g]' matches 'a', 'b', 'c', 'e', 'f' or 'g'. If the character after the [ is a ! then it is used for negation, so '[!a-c]' matches any character except 'a', 'b', or 'c'.

    Within a bracket expression, the '*', '?', and '\' characters match themselves. The '-' character matches itself if it is the first character within the brackets, or the first character after the !, if negating.

  • The '{ }' characters are a group of sub-patterns where the group returns a match if any sub-pattern in the group matches the contents of a target directory. The ',' character is used to separate sub-patterns. Groups cannot be nested. For example, the pattern '*.{csv, json}' matches file names ending with '.csv' or '.json'.

  • Leading dot characters in a file name are treated as regular characters in match operations. For example, the '*' glob pattern matches file name ".login".

  • All other characters match themselves.

Examples:

  • '*.csv' matches all files with a csv extension in the current directory only.
  • '**.csv' matches all files with a csv extension in the current directory and in all its subdirectories.
  • *[!{.pdf,.tmp}] excludes all files with the extension PDF or TMP.

File




Required for standard mode. Filename or a relative path to a file under the directory given in the Directory property. It should not start with a URL separator "/". The File property can be a JavaScript expression which will be evaluated with values from the input view document. When you press the Suggest icon, it will display a list of regular files under the directory in the Directory property. It generates the list by applying the value of the Filter property.

Use Hive tables if your input documents contains complex data types, such as maps and arrays.

Example: 

  • sample.orc
  • tmp/another.orc
  • _filename

Default value:  [None]

File action


Required. Select an action to take when the specified file already exists in the directory. Please note the Append file action is supported for SFTP, FTP, and FTPS protocols only.

Default value: [None]

File permissions for various users

Set the user and desired permissions.

Default value: [None]

Hive Metastore URL


This setting is used to assist in setting the schema along with the database and table setting.  If the data being written has a Hive schema, then the Snap can be configured to read the schema instead of manually entering it. Set the value to a Hive Metastore URL where the schema is defined.

Default value: [None]

Database

The Hive Metastore database where the schema is defined. See the Hive Metastore URL setting for more information.

Table

The table from which the schema in the Hive Metastore's database must be read. See the Hive Metastore URL setting for more information.

Compression

Required. The compression type to be used when writing the file. 

Column paths


Paths where the column values appear in the document. This property is required if the Hive Metastore URL property is empty.

Examples:

  • Column Name: Fun
  • Column Path: $column_from_input_data
  • Column Type: string

Default value: [None]

Snap Execution

Select one of the three modes in which the Snap executes. Available options are:

  • Validate & Execute: Performs limited execution of the Snap, and generates a data preview during Pipeline validation. Subsequently, performs full execution of the Snap (unlimited records) during Pipeline runtime.
  • Execute only: Performs full execution of the Snap during Pipeline execution without generating preview data.
  • Disabled: Disables the Snap and all Snaps that are downstream from it.

Troubleshooting

Writing to S3 files with HDFS version CDH 5.8 or later

When running HDFS version later than CDH 5.8, the Hadoop Snap Pack may fail to write to S3 files. To overcome this, make the following changes in the Cloudera manager:

  1. Go to HDFS configuration.
  2. In Cluster-wide Advanced Configuration Snippet (Safety Valve) for core-site.xml, add an entry with the following details:
    • Name: fs.s3a.threads.max
    • Value: 15
  3. Click Save.
  4. Restart all the nodes.
  5. Under Restart Stale Services, select Re-deploy client configuration.
  6. Click Restart Now.

Temporary Files

During execution, data processing on Snaplex nodes occurs principally in-memory as streaming and is unencrypted. When larger datasets are processed that exceeds the available compute memory, the Snap writes Pipeline data to local storage as unencrypted to optimize the performance. These temporary files are deleted when the Snap/Pipeline execution completes. You can configure the temporary data's location in the Global properties table of the Snaplex's node properties, which can also help avoid Pipeline errors due to the unavailability of space. For more information, see Temporary Folder in Configuration Options

Examples


 ORC Writer Writing to an HDFS Instance

ORC Writer Writing to an HDFS Instance

Here is an example of a ORC Writer configured to write to a local instance of HDFS. The output is written to /tmp/orc-output. The Hive Metastore used reads the schema from the employee_orc table from the masterdb database. No column paths or compression are used. For an example of the Schema, see the documentation on the Schema setting.



 ORC Writer Writing to an S3 Instance

ORC Writer Writing to an S3 Instance

Here is an example of a ORC Writer configured to write to a local instance of S3. The output is written to /tmp/orc-output. The Hive Metastore used reads the schema from the employee_orc table from the masterdb database. No column paths or compression are used. For an example of the Schema, see the documentation on the Schema setting.



See Also

Read more about ORC at the Apache project's website, https://orc.apache.org/

Snap Pack History

 Click to view/expand
Release Snap Pack VersionDateType  Updates
4.29main15993 Stable

Enhanced the AWS S3 Account for Hadoop account to include the S3 Region field that allows cross-region or proxied cross-region access to S3 buckets in the Parquet Reader and Parquet Writer Snaps.

4.28 Patch428patches15216 LatestAdded the AWS S3 Dynamic account for Parquet Reader and Parquet Writer Snaps.
4.28main14627 StableUpgraded with the latest SnapLogic Platform release.
4.27 Patch427patches13769 Latest

Fixed an issue with the Hadoop Directory Browser Snap where the Snap was not listing the files in the given directory for Windows VM.

4.27 Patch427patches12999 LatestEnhanced the Parquet Reader Snap with int96 As Timestamp checkbox, which when selected enables the Date Time Format field. You can use this field to specify a date-time format of your choice for int96 data-type fields. The int96 As Timestamp checkbox is available only when you deselect Use old data format checkbox.

4.27

main12833

 

Stable

Enhanced the Parquet Writer and Parquet Reader Snaps with Azure SAS URI properties, and Azure Storage Account for Hadoop with SAS URI Auth Type. This enables the Snaps to consider SAS URI given in the settings if the SAS URI is selected in the Auth Type during account configuration. 

4.26426patches12288 Latest

Fixed a memory leak issue when using HDFS protocol in Hadoop Snaps.

4.26main11181 StableUpgraded with the latest SnapLogic Platform release.
4.25 Patch425patches9975 Latest

Fixed the dependency issue in Hadoop Parquet Reader Snap while reading from AWS S3. The issue is caused due to conflicting definitions for some of the AWS classes (dependencies) in the classpath.

4.25main9554
 
Stable
  • Enhanced the HDFS Reader and HDFS Writer Snaps with the Retry mechanism that includes the following settings:
    • Number of Retries: Specifies the maximum number of retry attempts when the Snap fails to connect to the Hadoop server.
    • Retry Interval (seconds): Specifies the minimum number of seconds the Snap must wait before each retry attempt.
4.24 Patch424patches9262 Latest

Enhanced the AWS S3 Account for Hadoop to support role-based access when you select IAM role checkbox.

4.24 Patch424patches8876

 


Latest

Fixes the missing library error in Hadoop Snap Pack when running Hadoop Pipelines in JDK11 runtime.

4.24main8556
StableUpgraded with the latest SnapLogic Platform release.
4.23 Patch423patches7440 Latest

Fixes the issue in HDFS Reader Snap by supporting to read and write files larger than 2GB using ABFS(S) protocol.

4.23main7430
 
StableUpgraded with the latest SnapLogic Platform release.
4.22main6403
 
StableUpgraded with the latest SnapLogic Platform release.
4.21 Patchhadoop8853 Latest

Updates the Parquet Writer and Parquet Reader Snaps to support the yyyy-MM-dd format for the DATE logical type.

4.21snapsmrc542

 

StableUpgraded with the latest SnapLogic Platform release.
4.20 Patchhadoop8776 Latest

Updates the Hadoop Snap Pack to use the latest version of org.xerial.snappy:snappy-java for compression type Snappy, in order to resolve the java.lang.UnsatisfiedLinkError: org.xerial.snappy.SnappyNative.maxCompressedLength(I)I error.

4.20snapsmrc535
 
StableUpgraded with the latest SnapLogic Platform release.
4.19 Patchhadoop8270 Latest

Fixes an issue with the Hadoop Parquet Writer Snap wherein the Snap throws an exception when the input document includes one or all of the following:

  • Empty lists.
  • Lists with all null values.
  • Maps with all null values.
4.19snaprsmrc528
 
StableUpgraded with the latest SnapLogic Platform release.
4.18 Patchhadoop8033 Latest

Fixed an issue with the Parquet Writer Snap wherein the Snap throws an error when working with WASB protocol.

4.18snapsmrc523
 
Stable
4.17ALL7402
 
Latest

Pushed automatic rebuild of the latest version of each Snap Pack to SnapLogic UAT and Elastic servers.

4.17snapsmrc515
 
Latest

Added the Snap Execution field to all Standard-mode Snaps. In some Snaps, this field replaces the existing Execute during preview check box.

4.16snapsmrc508
 
Stable

Added a new property, Output for each file written, to handle multiple binary input data in the HDFS Writer Snap.

4.15snapsmrc500
 
Stable
  • Added two new Snaps: HDFS ZipFile Reader and HDFS ZipFile Writer.
  • Added support for the Data Catalog Snaps in Parquet Reader and Parquet Writer Snaps.
4.14 Patchhadoop5888 Latest

Fixed an issue wherein the Hadoop snaps were throwing an exception when a Kerberized account is provided, but the snap is run in a non-kerberized environment.

4.14snapsmrc490
 
Stable
  • Added the Hadoop Directory Browser Snap, which browses a given directory path in the Hadoop file system using the HDFS protocol and generates a list of all the files in the directory. It also lists subdirectories and their contents.
  • Added support for S3 file protocol in the ORC Reader, and ORC Writer Snaps.
  • Added support for reading nested schema in the Parquet Reader Snap.
4.13 Patchhadoop5318 Latest
  • Fixed the HDFS Reader/Writer and Parquet Reader/Writer Snaps, wherein Hadoop configuration information does not parse from the client's configuration files.
  • Fixed the HDFS Reader/Writer and Parquet Reader/Writer Snaps, wherein User Impersonation does not work on Hadooplex.
4.13

snapsmrc486

 
Stable
  • KMS encryption support added to AWS S3 account in the Hadoop Snap Pack.
  • Enhanced the Parquet Reader, Parquet Writer, HDFS Reader, and HDFS Writer Snaps to support WASB and ADLS file protocols.
  • Added the AWS S3 account support to the Parquet Reader and Writer Snaps. 
  • Added second input view to the Parquet Reader Snap that when enabled, accepts table schema.
  • Supported with AWS S3, Azure Data Lake, and Azure Storage Accounts.
4.12 Patchhadoop5132 Latest

Fixed an issue with the HDFS Reader Snap wherein the pipeline becomes stale while writing to the output view.

4.12

snapsmrc480

 
StableUpgraded with the latest SnapLogic Platform release.
4.11 Patchhadoop4275
Latest

Addressed an issue with Parquet Reader Snap leaking file descriptors (connections to HDFS data nodes). The Open File descriptor values work stable now,

4.11snapsmrc465
 
Stable

Added Kerberos support to the standard mode Parquet Reader and Parquet Writer Snaps.

4.10 Patchhadoop4001 Latest

Supported HDFS Writer to write to the encryption zone.

4.10 Patchhadoop3887 Latest

Addressed the suggest issue for the HDFS Reader on Hadooplex.

4.10 Patchhadoop3851 Latest
  • ORC supports read/write from local file system.
  • Addressed an issue to bind the Hive Metadata to Parquet Writer Schema at Runtime.
4.10 Patchhadoop3838 Latest

Made HDFS Snaps work with Zone encrypted HDFS.

4.10

snapsmrc414

 
Stable
  • Updated the Parquet Writer Snap with Partition by property to support the data written into HDFS based on the partition definition in the schema in Standard mode.
  • Support for S3 accounts with IAM Roles added to Parquet Reader and Parquet Writer
  • HDFS Reader/Writer with Kerberos support on Groundplex (including user impersonation).
4.9 Patchhadoop3339 Latest

Addressed the following issues:

  • ORC Reader passing, but ORC Writer failing when run on a Cloudplex.
  • ORC Reader Snap is not routing error to error view.
  • Intermittent failures with the ORC Writer
4.9.0 Patchhadoop3020 Latest

Added missing dependency org.iq80.snappy:snappy to Hadoop Snap Pack.

4.9snapsmrc405
 
StableUpgraded with the latest SnapLogic Platform release.
4.8

snapsmrc398

 
Stable

Snap-aware error handling policy enabled for Spark mode in Sequence Formatter and Sequence Parser. This ensures the error handling specified on the Snap is used.

4.7.0 Patchhadoop2343 Latest

Spark Validation: Resolved an issue with validation failing when setting the output file permissions.

4.7

snapsmrc382

 
Stable
  • Updated the HDFS Writer and HDFS Reader Snaps with Azure Data Lake account for standard mode pipelines.
  • HDFS Writer: Spark mode support added to write to a specified directory in an Azure Storage Layer using the wasb file system protocol.
  • HDFS Reader: Spark mode support added to read a single file or an HDFS directory from an Azure Storage Layer.
4.6snapsmrc362
 
Stable
  • The following Snaps now support error view in Spark mode: HDFS Reader, Sequence Parser.
  • Resolved an issue in HDFS Writer Snap that sends the same data in output & error view.
4.5

snapsmrc344

 
Stable
  • HDFS Reader and HDFS Writer Snaps updated to support IAM Roles for Amazon EC2.
  • Support for Spark mode added to Parquet Reader, Parquet Writer
  • The HBase Snaps are no longer available as of this release.
4.4.1
 Stable
  • Resolved an issue with Sequence Formatter not working in Spark mode.
  • Resolved an issue with HDFSReader not using the filter set when configuring SparkExec paths.
4.4
 Stable
  • NEW! Parquet Reader and Writer Snaps
  • NEW! ORC Reader and Writer Snaps
  • Spark support added to the HDFS Reader, HDFS Writer, Sequence Formatter, and Sequence Parser Snaps.
  • Behavior change: HDFS Writer in SnapReduce mode now requires the File property to be blank.
4.3.2
 Stable
  • Implemented wasbs:// protocol support in Hadoop Snap Pack.
  • Resolved an issue with HDFS Reader unable to read all files under a folder (including all files under its subfolders) using the ** filter.