Snowflake - Unload

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Overview

Snap type:

Read


Description:

This Snap unloads the result of a query to a file or files stored on the Snowflake stage, or on an external S3 workspace, or on Azure Storage Blob, if required. The target Snowflake table is not modified. Once the data is unloaded to the storage, users can get the file either using Snowflake GET or S3 file reader.

Expected upstream Snaps: Any Snap with a document output view

Expected downstream Snaps: Any Snap with a document input view, such as JSON Formatter, Mapper, and so on. The CSV Formatter Snap cannot be connected directly to this Snap since the output document map data is not flat.

Expected input: Key-value map data to evaluate expression properties of the Snap

Expected output:  Document with Snowflake response, query command and the location Url for the unloaded file. 

The Snap behaves the same on a Groundplex as it does in a Cloudplex.

Prerequisites:

You should have minimum permissions on the database to execute Snowflake Snaps. To understand if you already have them, you must retrieve the current set of permissions. The following commands enable you to retrieve those permissions.

SHOW GRANTS ON DATABASE <database_name>
 
SHOW GRANTS ON SCHEMA <schema_name>
 
SHOW GRANTS TO USER <user_name>

Security Prerequisites: You should have the following permission in your Snowflake account to execute this Snap: 

  • Usage (DB and Schema): Privilege to use database, role, and schema.

The following commands enable minimum privileges in the Snowflake Console:

grant usage on database <database_name> to role <role_name>;
grant usage on schema <database_name>.<schema_name>;

For more information on Snowflake privileges, refer to Access Control Privileges.

The below are mandatory when using an external staging location:

When using an Amazon S3 bucket for storage:

  • The Snowflake account should contain S3 Access-key ID, S3 Secret key, S3 Bucket and S3 Folder.
  • The Amazon S3 bucket where the Snowflake will write the output files must reside in the same region as your cluster.

When using a Microsoft Azure storage blob:

  • A working Snowflake Azure database account.


Internal SQL Commands

This Snap uses the COPY INTO command internally. It enables unloading data from a table (or query) into one or more files in one of the following locations:

  • Named internal stage (or table/user stage).
  • Named external stage, that references external location, such as, Amazon S3, Google Cloud Storage, or Microsoft Azure.
  • External location, such as, Amazon S3, Google Cloud Storage, or Microsoft Azure.
Support and limitations:
  • Works in Ultra Task Pipelines.
  • Snowflake provides the option to use the Cross Account IAM into the external staging. You can adopt the cross account access through option Storage Integration. With this setup, you don’t need to pass any credentials around and access the storage only using the named stage or integration object. For more details: Configuring Cross Account IAM Role Support for Snowflake Snaps.
Account: 

This Snap uses account references created on the Accounts page of SnapLogic Manager to handle access to this endpoint. This Snap requires a Snowflake Account with S3 or Microsoft Azure properties. See Snowflake Account for information on setting up this type of account.
 

Views:
Input

This Snap has at most 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.

Query



Required. Defines a SELECT query. The results of the query are unloaded. In most cases, it is worthwhile to unload data in sorted order by specifying an ORDER BY clause in the query; this approach will save the time Required. to sort the data when it is reloaded.

Example: SELECT * FROM public.company ORDER BY id

Default value: None


Staging Location


The staging location for the unload. The expected input for this should be a path to a file or filename-prefix.

The options available include:

  • External: Location that is not managed by Snowflake. The location should be an AWS S3 Bucket or Microsoft Azure Storage blob.
  • Internal: Location that is managed by Snowflake.

Default value: Internal


Target


Required. The staging area where the unloaded file(s) are placed. If the staging location is external, it will be put under the S3 Bucket or Microsoft Azure Storage Blob specified for the Account. If the staging location is internal,  the files will be placed in the user’s home folder. 

ExampleTestFolder/file_name_prefix

Default value:  None


Storage Integration

The pre-defined storage integration is used to authenticate the external stages.

Default value: None

File Format Type


The format type for the unloaded file. The options available are None, CSV, and CUSTOMIZED.

If CUSTOMIZED is chosen, then the customized format identifier must be specified.

Default value: None


Customized format identifier


The file format object to use for unloading data from the table. The field is valid only when the File format type is specified as Customized. Otherwise, this will be ignored.
Default value: None

File format option


Specify the file format option. Separate multiple options by using blank spaces and commas.

You can use various file format options including binary format which passes through in the same way as other file formats. See File Format Type Options for more information.

Before loading binary data into Snowflake, you must specify the binary encoding format, so that the Snap can decode the string type to binary types before loading into Snowflake. This can be done by specifying the following binary file format:

BINARY_FORMAT=xxx (Where XXX = HEX|BASE64|UTF-8)

However, the file you upload and download must be in similar formats. For instance, if you load a file in HEX binary format, you should specify the HEX format for download as well.

Default value: None

Copy options 


Overwrite


If selected, the UNLOAD overwrites the existing files, if any, in the location where files are stored.

If unselected, the option does not remove the existing files or overwrite.

Default value: Not selected


Generate single file


If selected, the UNLOAD will generate a single file. If it is not selected, the filename prefix needs to be included in the path.

Default value: Not selected


Max file size


Maximum size (in bytes) of each file to be generated in parallel per thread. The number should be greater than 0, If it is less than or equals 0, the Snap will use the default size for snowflake: 16000000 (16MB).

Default value: 0


Encryption type

Specifies the type of encryption to be used on the data. The available encryption options are:

  • None: Files do not get encrypted.
  • Server Side Encryption: The output files on Amazon S3 are encrypted with server-side encryption.
  • Server-Side KMS Encryption: The output files on Amazon S3 are encrypted with an Amazon S3-generated KMS key. 

Default value: No default value.

The KMS Encryption option is available only for S3 Accounts (not for Azure Accounts) with Snowflake.

KMS key

The KMS key that you want to use for S3 encryption. For more information about the KMS key, see AWS KMS Overview and Using Server Side Encryption.

Default value: No default value.

This property applies only when you select Server-Side KMS Encryption in the Encryption Type field above.

Include column headings

If selected, the table column heading will be included in the generated files. If multiple files are generated, the heading will be included in every file.

Default value: Not selected 


Validation Mode


This mode is useful for visually verifying the data before unloading it. If this is NONE, validation mode is disabled or, the unloaded data will not be written to the file. Instead, it will be sent as a response to the output.

The options available include:

  • NONE
  • RETURN_ROWS

Default value: NONE  


Manage Queued Queries

Select this property to decide whether the Snap should continue or cancel the execution of the queued Snowflake Execute SQL queries when you stop the pipeline.

If you select Cancel queued queries when the pipeline is stopped or if it fails, then the read queries under execution are canceled, whereas the write queries under execution are not canceled. Snowflake internally determines which queries are safe to be canceled and cancels those queries.

Default value: Continue to execute queued queries when the pipeline is stopped or if it fails

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

The preview on this Snap will not execute the Snowflake UNLOAD operation. Connect a JSON Formatter and a File Writer Snaps to the error view and then execute the pipeline. If there is any error, you will be able to preview the output file in the File Writer Snap for the error information.

Examples

Unloading Data (Including Binary Data Types) From Snowflake Database

The following example Pipeline demonstrates how you can unload binary data as a file and load it into an S3 bucket.

First, we configure the Snowflake - Unload Snap by providing the following query:

select * from EMP2  this query unloads data from EMP2 table.

Note that we set the File format option as BINARY_FORMAT='UTF-8' to enable the Snap to pass binary data.

Upon validation, the Snap shows the unloadRequest and unloadDestination in its preview.


We connect
 the JSON Formatter Snap to Snowflake - Unload Snap to transform the binary data to JSON format, and finally write this output to a file in S3 bucket using the File Writer Snap. Upon validation, the File Writer Output Snap writes the output (unload request)- the output preview is as shown below.

Download this Pipeline.


The following example illustrates the usage of the Snowflake Unload Snap. 

 

In this example, we run the Snowflake SQL query using the Snowflake Unload Snap. The Snap selects the data from the table, @ADOBEDATA2 and writes the records to the table, adobedatanullif  using the File Writer.

Connect the JSON formatter Snap to convert the predefined CSV file format to JSON and write the data using the File Writer Snap.

Successful execution of the pipeline gives the below output preview: 

  File Modified

File Example_Snowflake_Unload_Binary_DataType.slp

Apr 22, 2021 by Kalpana Malladi

Snap Pack History

 Click to view/expand
Release Snap Pack VersionDateType  Updates
4.27427patches12999 LatestEnhanced the Snowflake SCD2 Snap to support Pipeline parameters for Natural key and Cause-historization fields.
4.27main12833 Stable
  • Enhanced the Snowflake S3 Database Account to skip batch execution, when the Batch size value is one. When the Batch size is greater than one, the batch is executed.
  • Added the following truncate options to Snowflake - Bulk Load Snap to truncate existing data before performing data load to more efficiently transfer data where possible.
    • Truncate data: Truncates existing data before performing data load. 
    • Truncate columns: Truncates column values that are larger than the maximum column length in the table.
  • Enhanced the Snowflake - Execute Snap to invoke stored procedures.
4.26 Patch426patches11469 LatestFixed an issue with Snowflake Insert and Snowflake Bulk Load Snaps where the schema names or database names containing underscore (_) caused the time out of Pipelines.
4.26main11181 Stable
  • Enhanced Snowflake - Lookup and Snowflake SCD2 Snaps with the Input Date Format field to select from the following two options:
    • Continue to execute the snap with the given input Date format
    • Auto Convert the format to Snowflake default format
  • Added a new account type Snowflake Google Storage Database to connect to Google Cloud Storage to load data.
  • Added support for all existing Snowflake Snap accounts to connect to a Snowflake instance hosted on the Google Cloud Platform

4.25425patches10190LatestEnhanced the Snowflake S3 Database and Snowflake S3 Dynamic accounts with a new field S3 AWS Token that allows you to connect to private and protected Amazon S3 buckets.
4.25main9554
 
StableUpgraded with the latest SnapLogic Platform release.

4.24 Patch

424patches8905 LatestEnhanced the Snowflake - Bulk Load Snap to allow transforming data using a new field Select Query before loading data into the Snowflake database. This option enables you to query the staged data files by either reordering the columns or loading a subset of table data from a staged file. This Snap supports CSV and JSON file formats for this data transformation.
4.24main8556
Stable

Enhanced the Snowflake - Select Snap to return only the selected output fields or columns in the output schema (second output view) using the Fetch Output Fields In Schema check box. If the Output Fields field is empty all the columns are visible.

4.23 Patch

423patches7905 Latest

Fixed the performance issue in the Snowflake - Bulk Load Snap while using External Staging on Amazon S3.

4.23main7430
 
Stable
4.22 Patch 422patches7246 Latest

Fixes an issue with the Snowflake Snaps that fail while displaying the same error message, javax.management.MalformedObjectNameException: Invalid character '=' in value part of property, repeatedly when there is “=“ or ”:” in the Snowflake URL connection.

4.22 Patch

422patches6849 Latest
4.22main6403
 
StableUpgraded with the latest SnapLogic Platform release.

4.21 Patch

421patches6272 Latest

Fixes the issue where Snowflake SCD2 Snap generates two output documents despite no changes to Cause-historization fields with DATE, TIME and TIMESTAMP Snowflake data types, and with Ignore unchanged rows field selected.

4.21 Patch

421patches6144 Latest
  • Fixed the following issues with DB Snaps:
    • The connection thread waits indefinitely causing the subsequent connection requests to become unresponsive.
    • Connection leaks occur during Pipeline execution.
  • Fixed the exception RefCnt has gone negative across the Snaps in Snowflake Snap Pack.

4.21 Patch 

db/snowflake8860 Latest

Added a new field, Handle Timestamp and Date Time Data, to Snowflake Lookup Snap. This field enables you to decide whether the Snap should translate UTC time to your local time and the format of the Date Time data.

4.21 Patch

MULTIPLE8841 Latest

Fixed the connection issue in Database Snaps by detecting and closing open connections after the Snap execution ends. 

4.21snapsmrc542

 

StableUpgraded with the latest SnapLogic Platform release.
4.20 Patch db/snowflake8800 Latest
  • Certifies the Snowflake Snap Pack against JDBC Driver version 3.12.3.

Snowflake Execute and Multi-Execute Snaps may break existing Pipelines if the JDBC Driver is updated to a newer version.

With the updated JDBC driver (version 3.12.3), the Snowflake Execute and Multi-Execute Snaps' output displays a Status of "-1" instead of "0" without the Message field upon successfully executing DDL statements. If your Pipelines use these Snaps and downstream Snaps use the Status field's value from these, you must modify the downstream Snaps to proceed on a status value of -1 instead of 0.

This change in the Snap behavior follows from the change introduced in the Snowflake JDBC driver in version 3.8.1:
"Statement.getUpdateCount() and PreparedStatement.getUpdateCount() return the number of rows updated by DML statements. For all other types of statements, including queries, they return -1."

4.20 Patch db/snowflake8758 Latest

Re-release of fixes from db/snowflake8687 for 4.20: Fixes the Snowflake Bulk Load snap where the Snap fails to load documents containing single quotes when the Load empty strings checkbox is not selected.

4.20snapsmrc535
 
StableUpgraded with the latest SnapLogic Platform release.
4.19 Patch db/snowflake8687 Latest

Fixed the Snowflake Bulk Load snap where the Snap fails to load documents containing single quotes when the Load empty strings checkbox is not selected.

4.19 Patch 

db/snowflake8499 Latest

Added the property Handle Timestamp and Date Time Data to Snowflake - Execute and Snowflake - Select Snaps. This property enables you to decide whether the Snap should translate UTC time to your local time.

4.19 Patch 

db/snowflake8412 Latest

Fixed an issue with the Snowflake - Update Snap wherein the Snap is unable to perform operations when:

  • An expression is used in the Update condition property.
  • Input data contain the character '?'.
4.19snaprsmrc528
 
Stable
  • Added a new field-set, Auto Historization Query, in the Snowflake SCD2 Snap to support auto-historization of column data. With this enhancement you can detect whether the incoming record is a historical event or a current event.  
  • Raised the minimum buffer size in the Snowflake - Bulk Upsert and Snowflake - Bulk Load Snaps to 6 MB.
4.18 Patch db/snowflake8044 Latest

Fixed an issue with the Snowflake - Select Snap wherein the Snap converts the Snowflake-provided timestamp value to the local timezone of the account.

4.18 Patch 

db/snowflake8044 Latest

Enhanced the Snap Pack to support AWS SDK 1.11.634 to fix the NullPointerException issue in the AWS SDK. This issue occurred in AWS-related Snaps that had HTTP or HTTPS proxy configured without a username and/or password. 

4.18 Patch

MULTIPLE7884 Latest

Fixed an issue with the PostgreSQL grammar to better handle the single quote characters.

4.18 Patch 

db/snowflake7821 Latest

Fixed an issue with the Snowflake - Execute Snap wherein the Snap is unable to support the '$' character in query syntax.

4.18 Patch

MULTIPLE7778 Latest

Updated the AWS SDK library version to default to Signature Version 4 Signing process for API requests across all regions.

4.18 Patch 

db/snowflake7739 Latest
  • Fixed an issue with the Snowflake - Bulk Upsert Snap wherein the Snap fails when using a pipeline parameter in Key columns.
  • Fixed an issue with the Snowflake - Unload Snap wherein the Snap does not abort the query when you stop the Pipeline execution.
4.18snapsmrc523
 
Stable

Added the Use Result Query property to the Multi Execute Snap, which enables you to write results to an output view.

4.17ALL7402
 
Latest

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

4.17 Patch 

db/snowflake7396 Latest

Fixed an issue wherein bit data types in the Snowflake - Select table convert to true or false instead of 0 or 1.

4.17 Patch 

db/snowflake7334 Latest

Added AWS Server-Side Encryption support for AWS S3 and AWS KMS (Key Management Service) for Snowflake Bulk Load, Snowflake Bulk Upsert, and Snowflake Unload Snaps.

4.17snapsmrc515
 
Latest
  • Fixed an issue with the Snowflake Execute Snap wherein the Snap would send the input document to the output view even if the Pass through field is not selected in the Snap configuration. With this fix, the Snap sends the input document to the output view, under the key original, only if you select the Pass through field.
  • Added the Snap Execution field to all Standard-mode Snaps. In some Snaps, this field replaces the existing Execute during preview check box.
4.16 Patch db/snowflake6945 Latest

Fixed an issue with the Snowflake Lookup Snap failing when Date datatype is used in JavaScript functions.

4.16 Patch 

db/snowflake6928 Latest

Added support for file format options for input data from upstream Snaps, to the Snowflake Bulk Load Snap.

4.16 Patch 

db/snowflake6819 Latest
  • Snowflake Bulk Load: Added new property, Buffer size (MB). Configure this to specify the size limit of each buffer when writing to external staging systems such as S3. 
  • Fixed an issue with the Lookup Snap passing data simultaneously to output and error views when some values contained spaces at the end.
4.16snapsmrc508
 
Stable
  • Snowflake Account: Added the ability to use SnapLogic to securely connect to and query a Snowflake instance using Azure Blob as its storage layer. 
  • Snowflake Account: Added support for Snowflake JDBC JAR version 3.6.17. 
  • Snowflake Unload, Bulk Load, and Bulk Upsert: Updated the Snaps to enable SnapLogic users to successfully connect to a Snowflake instance to query, bulk load, and unload data from Azure Blob storage.
4.15snapsmrc500
 
Stable
  • Added two new Snaps, Snowflake - Multi Execute, and Snowflake SCD2. Snowflake - Multi Execute is used for executing multiple DDL and DML queries on the Snowflake DB. Snowflake SCD2 is used for Type 2 field historization. 
  • Enhanced the Snowflake Bulk Upsert Snaps to improve the Snaps performance.
  • Enhanced the Snowflake Snap Pack to reflect Azure certification.
4.14snapsmrc490
 
StableUpgraded with the latest SnapLogic Platform release.
4.13

snapsmrc486

 
StableUpgraded with the latest SnapLogic Platform release.
4.12

snapsmrc480

 
StableUpgraded with the latest SnapLogic Platform release.
4.11 PatchMULTIPLE4377 Latest

Fixed a document call issue that was slowing down the Snowflake Bulk Load Snap.

4.11 Patch 

db/snowflake4283 Latest

Snowflake Bulk Load - Fixed an issue by adding PUT command to the list of DDL command list for Snowflake.

4.11 Patch 

db/snowflake4273 Latest

Snowflake Bulk Load - Resolved an issue with Snowflake Bulk Load Delimiter Consistency (comma and newline).

4.11snapsmrc465
 
StableUpgraded with the latest SnapLogic Platform release.

4.10 Patch

snowflake4133
Latest

Updated the Snowflake Bulk Load Snap with Preserve case sensitivity property to preserve the case sensitivity of column names.

4.10

snapsmrc414

 
Stable
  • Updated the Snowflake Bulk Load Snap with Load empty strings property for the empty string values in the input documents to be loaded as empty strings to the string-type fields.
  • Updated the Snowflake Bulk Load Snap with Table Columns to support the order of the entries on the staged files that contain a subset of the columns in the Snowflake table.
  • Added the property Use Result Query to view the output preview field with a result statement.
  • Tested for the JDBC jar version 3.1.1 on the Database and the Dynamic accounts.

4.9.0 Patch

snowflake3234 Latest

Enhanced Snowflake - Execute Snap results to include additional details

4.9.0 Patch

snowflake3125 Latest

Addressed an issue in Snowflake Bulk Load where the comma character in a value is not escaped.

4.9snapsmrc405
 
StableJDBC Driver Class property added to enable the user to custom configure the JDBC driver in the Database and the Dynamic accounts.

4.8.0 Patch

snowflake2760 Latest

Potential fix for JDBC deadlock issue.

4.8.0 Patch

snowflake2739 Latest

Addressed an issue with the Snowflake schema not correctly represented in the Mapper Snap.

4.8

snapsmrc398

 
Stable
  • Info tab added to accounts.
  • Database accounts now invalidate connection pools if account properties are modified and login attempts fail.
  • Enhanced the default count of input and output view (UI) behavior of the Snaps for better user experience. 

    Snowflake Snap Pack

    Views

    Bulk Load

    Bulk Upsert

    Insert

    Update

    Delete

    Execute

    Unload

    Select

    Table List

    Lookup

    Initial (4.7)

    Input-Output views

    1-0

    1-0

    1-0

    1-0

    0-0

    0-0

    0-0

    0-1

    0-1

    0-1

    Current (4.8)

    Input-Output views

    1-1

    1-1

    1-1

    1-1

    0-1

    0-1

    0-1

    0-1

    0-1

    0-1

    Note that the Snowflake Select, Table List and Lookup Snap views remain unchanged.