ORC Reader

Owned by Lakshmi Manda
Last updated: Jul 31, 2024 by Kalpana Malladi

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Snap type:

Read

Description:

This Snap reads ORC files from SLDB, HDFS, S3, and WASB, and converts the data into documents.

  • Expected upstream Snaps: [None]
  • Expected downstream Snaps: Any data transformation or formatting Snaps, such as Mapper or JSON Formatter Snaps.
  • Expected input: ORC files from SLDB, HDFS, S3, and WASB.
  • Expected output: A document with the columns and data of the Parquet file.

This Snap supports both HDFS (non-Kerberos) and ABFS (Azure Data Lake Storage Gen 2 ), WASB(Azure storage), and S3 protocols.

Prerequisites:

None

Support:
  • Works with SLDB, HDFS, S3, and WASB.
  • Works in Ultra Tasks.
Known Issue:

The upgrade of Azure Storage library from v3.0.0 to v8.3.0 has caused the following issue when using the WASB protocol:
When you use invalid credentials for the WASB protocol in Hadoop Snaps (HDFS Reader, HDFS Writer, ORC Reader, Parquet Reader, Parquet Writer), the pipeline does not fail immediately, instead it takes 13-14 minutes to display the following error:

reason=The request failed with error code null and HTTP code 0. , status_code=error

SnapLogic® is actively working with Microsoft®Support to resolve the issue.

Learn more about Azure Storage library upgrade.

Account: 

Depending on the source of the data you want to read, you will need to provide valid account information for either AWS S3 Account or Azure Storage Account.

Views:
InputThis Snap has at most one document input view.
OutputThis Snap has exactly 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 of the Snap. You can modify this to be more specific, especially if you have more than one of the same Snap in your pipeline.

Directory


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>
  • WASB: wasb:///<WASB_directory>/<file_name>
  • ABFS:
    • abfs:///<filesystem>/<path>/
    • abfs://<filesystem>@<accountname>.<endpoint>/<path>
  • ABFSS
    • abfss:///<filesystem>/<path>/
    • abfss://<filesystem>@<accountname>.<endpoint>/<path>

When you use the ABFS protocol to connect to an endpoint, the account name and endpoint details provided in the URL override the corresponding values in the Account Settings fields.

With the ABFS protocol, SnapLogic creates a temporary file to store the incoming data. Therefore, the hard drive where the JCC is running should have enough space to temporarily store all the account data coming in from ABFS.

The Directory property is not used in the pipeline execution or preview, and is 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:

  • wasb:///snaplogic/srikanth_test123/RedWoodcity

Default value: hdfs://<hostname>:<port>/

Filter

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.

Example: 

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

Default value:  [None]

Snap Execution

Select one of the following three modes in which the Snap executes:

  • 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.

Default Value: Execute only




Example: Validate & Execute

Examples

 Reading from a Local Instance of HDFS

Reading from a Local Instance of HDFS

You can configure the ORC Reader Snap to read from a specific directory in a local HDFS instance. In the example below, it reads from the file.orc file in the /tmp directory.



 Reading from a Local Instance of S3

Reading from a Local Instance of S3

You can configure the ORC Reader Snap to read from a specific directory in a local S3 instance. In the example below, it reads from the /<file-path>/file.orc file.


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. 

See Also


 Click to view/expand
Release Snap Pack VersionDateType  Updates
November 2024main29029 StableUpdated and certified against the current SnapLogic Platform release.

August 2024

main27765

 

Stable

Upgraded the org.json.json library from v20090211 to v20240303, which is fully backward compatible.

May 2024437patches27226 -

The upgrade of the Azure Storage library from v3.0.0 to v8.3.0 has impacted the Hadoop Snap Pack causing the following issue when using the WASB protocol.

Known Issue

When you use invalid credentials for the WASB protocol in Hadoop Snaps (HDFS Reader, HDFS Writer, ORC Reader, Parquet Reader, Parquet Writer), the pipeline does not fail immediately, instead it takes 13-14 minutes to display the following error:

reason=The request failed with error code null and HTTP code 0. , status_code=error

SnapLogic® is actively working with Microsoft®Support to resolve the issue.

Learn more about the Azure Storage Library Upgrade.

May 2024437patches27471 Latest

Fixed a resource leak issue with the following Hadoop Snaps, which involved too many stale instances of ProxyConnectionManager and significantly impacted memory utilization.

May 2024437patches26370 Latest

Enhanced the HDFS Writer Snap with the Write empty file checkbox to enable you to write an empty or a 0-byte file to all the supported protocols that are recognized and compatible with the target system or destination.

May 2024main26341 Stable

The Azure Data Lake Account has been removed from the Hadoop Snap Pack because Microsoft retired the Azure Data Lake Storage Gen1 protocol on February 29, 2024. We recommend replacing your existing Azure Data Lake Accounts (in Binary or Hadoop Snap Packs) with other Azure Accounts.

February 2024

436patches25902

 Latest

Fixed a memory management issue in the HDFS Writer, HDFS ZipFile Writer, ORC Writer, and Parquet Writer Snaps, which previously caused out-of-memory errors when multiple Snaps were used in the pipeline. The Snap now conducts a pre-allocation memory check, dynamically adjusting the write buffer size based on available memory resources when writing to ADLS.

February 2024435patches25410Latest

Enhanced the AWS S3 Account for Hadoop with an External ID that enables you to access Hadoop resources securely.

February 2024main25112 StableUpdated and certified against the current SnapLogic Platform release.
November 2023435patches23904 Latest

  • Fixed an issue with the Parquet Writer Snap that displayed an error Failed to write parquet data when the decimal value passed from the second input view exceeded the specified scale.

  • Fixed an issue with the Parquet Writer Snap that previously failed to handle the conversion of BigInt/int64 (larger numbers) after the 4.35 GA now converts them accurately.

November 2023435patches23780 Latest

Fixed an issue related to error routing to the output view. Also fixed a connection timeout issue.

November 2023main23721StableUpdated and certified against the current SnapLogic Platform release.
August 2023434patches23173 Latest

Enhanced the Parquet Writer Snap with a Decimal Rounding Mode dropdown list to enable the rounding method for decimal values when the number exceeds the required decimal places.

August 2023434patches22662 Latest

  • Enhanced the Parquet Writer Snap with the support for LocalDate and DateTime. The Snap now shows the schema suggestions for LocalDate and DateTime correctly.

  • Enhanced the Parquet Reader Snap with the Use datetime types checkbox that supports LocalDate and DateTime datatypes.

Behavior change:

When you select the Use datetime types checkbox in the Parquet Reader Snap, the Snap displays the LocalDate and DateTime in the output for INT32 (DATE) and INT64 (TIMESTAMP_MILLIS) columns. When you deselect this checkbox, the columns retain the previous datatypes and display string and integer values in the output.

August 2023

main22460

 

Stable

Updated and certified against the current SnapLogic Platform release.

May 2023433patches22180 Latest

Introduced the HDFS Delete, which deletes the specified file, group of files, or directory from the supplied path and protocol in the Hadoop Distributed File System (HDFS).

May 2023433patches21494 LatestThe Hadoop Directory Browser Snap now returns all the output documents as expected after implementing pagination for the ABFS protocol.
May 2023main21015 StableUpgraded with the latest SnapLogic Platform release.
February 2023

432patches20820

 Latest

Fixed an authorization issue that occurs with the Parquet Writer Snap when it receives empty document input.

February 2023432patches20209 Latest

The Apache Commons Compress library has been upgraded to version 1.22.

February 2023432patches20139 Latest

The Kerberos Account that is available for a subset of snaps in the Hadoop Snap pack now supports a configuration that enables you to read from and write to the Hadoop Distributed File System (HDFS) managed by multiple Hadoop clusters. You can specify the location of the Hadoop configuration files in the Hadoop config directory field. The value in this field overrides the value that is set on the Snaplex system property used for configuring a single cluster. 

February 2023

main19844 StableUpgraded with the latest SnapLogic Platform release.
November 2022main18944 Stable

The AWS S3 and S3 Dynamic accounts now support a maximum session duration of an IAM role defined in AWS.

August 2022main17386 StableExtended the AWS S3 Dynamic Account support to ORC Reader and ORC Writer Snaps to support AWS Security Token Service (STS) using temporary credentials.
4.29 Patch429patches16630 Latest
  • Extended the AWS S3 Dynamic Account support to ORC Reader and ORC Writer Snaps to support AWS Security Token Service (STS) using temporary credentials.
  • Fixed an issue in the following Snaps that use AWS S3 dynamic account, where the Snaps displayed the security credentials like Access Key, Secret Key, and Security Token in the logs. Now, the security credentials in the logs are blurred for the Snaps that use AWS S3 dynamic account.
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