PostgreSQL - Select

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Snap type:

Read

Description:

This Snap allows you to fetch data from a database by providing a table name and configuring the connection. The Snap produces the records from the database on its output view which can then be processed by a downstream Snap. 

JSON paths can be used in a query and will have values from an incoming document substituted into the query. However, documents missing values for a given JSON path will be written to the Snap's error view. After a query is executed, the query's results are merged into the incoming document overwriting any existing keys' values. The original document is output if there are no results from the query.


Queries produced by the Snap have an equivalent format:

SELECT * FROM [table] WHERE [where clause] ORDER BY [ordering] LIMIT [limit] OFFSET [offset]

If more powerful functionality is desired, then the Execute Snap should be used.

Known issue: The SQL statement will return a PGObject when returning non-standard types. You must use the Execute Snap in these cases.

Non-standard types include standard PostgreSQL extensions such as JSON or XML, types defined in third party extensions such as PostGIS, or types defined via CREATE TYPE color AS ENUM (RED, GREEN, BLUE).
Prerequisites:

[None]

Support and limitations:

Works in Ultra Pipelines.

Account: 

This Snap uses account references created on the Accounts page of SnapLogic Manager to handle access to this endpoint. See Configuring PostgreSQL Accounts for information on setting up this type of account.

Views:
Input

This Snap has at most one document input view. If the input view is defined, then the where clause can substitute incoming values for a given expression (in such as to use it as a lookup).

Output

This Snap has one output view by default and produces one document for each row in the table.  A second view can be added to dump out the metadata for the table as a document.  The metadata document can then be fed into the second input view of PostgreSQL Insert Snap so that the table is created in PsotgreSQL with a similar schema as the source table.

Error

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

Because the Snap must report what is reported by the database, the Snap sends all records to the error view and no record to the output view. If you want to see accurate results for each row you must set the batch size to 1 and execute the pipeline.


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.

Schema name



The database schema name. Selecting a schema filters the Table name list to show only those tables within the selected schema. The property is suggestible and will retrieve available database schemas during suggest values.

Default value: [None]

Table name

Required. Name of the table to execute a select query on.

Example: people

Default value: [None]

Where clause 

Where clause of the select statement. This supports document value substitution (such as $person.firstname will be substituted with the value found in the incoming document at the path). 

Examples

Without using expressions

Using expressions

  • "EMPNO=$EMPNO and ENAME=$EMPNAME"

  • email = $email 

  • emp=$emp

  • "emp='" + $emp + "'"

  • "EMPNO=" + $EMPNO + " and ENAME='" + $EMPNAME+ "'"

Caution

Using expressions that join strings together to create SQL queries or conditions has a potential SQL injection risk and is hence unsafe. Ensure that you understand all implications and risks involved before using concatenation of strings with '=' Expression enabled. 

Order by: Column names 

Enter in the columns in the order in which you want to order by. The default database sort order will be used.

Example

name
email 

Limit offset

Number of rows to return from the query.
Example: 10

Default value: [None] 

Limit rows 

Number of rows to return from the query.
Example: 10

Default value: [None]

Output fields

 Enter or select output field names for SQL SELECT statement. To select all fields, leave it at default.

Example: email, address, first, last, etc.

Default value: [None]

Fetch Output Fields In Schema

Select this check box to include only the selected fields or columns in the Output Schema (second output view). If you do not provide any Output fields, all the columns are visible in the output.
If you provide output fields, we recommend you to select Fetch Output Fields In Schema check box.

Default value: Not selected

Pass through

 

If checked, the input document will be passed through to the output view under the key 'original'.

Default value: Selected

Ignore empty result

 

If selected, no document will be written to the output view when a SELECT operation does not produce any result. If this property is not selected and the Pass through property is selected, the input document will be passed through to the output view.

Default value: Not selected

Number of retries

Specifies the maximum number of attempts to be made to receive a response. The request is terminated if the attempts do not result in a response.

If the value is larger than 0, the Snap first downloads the target file into a temporary local file. If any error occurs during the download, the Snap waits for the time specified in the Retry interval and attempts to download the file again from the beginning. When the download is successful, the Snap streams the data from the temporary file to the downstream Pipeline. All temporary local files are deleted when they are no longer needed.

Ensure that the local drive has sufficient free disk space to store the temporary local file.

Example: 3

Default value: 0

Retry interval (seconds)

Specifies the time interval between two successive retry requests. A retry happens only when the previous attempt resulted in an exception. 

Example:  10

Default value: 1

Auto commit

Select one of the options for this property to override the state of the Auto commit property on the account. The Auto commit at the Snap-level has three values: TrueFalse, and Use account setting. The expected functionality for these modes are:

  •  True - The Snap will execute with auto-commit enabled regardless of the value set for Auto commit in the Account used by the Snap.
  •  False - The Snap will execute with auto-commit disabled regardless of the value set for Auto commit in the Account used by the Snap.
  • Use account setting - The Snap will execute with Auto commit property value inherited by the Account used by the Snap.

Default value: False

Match data types

Conditional. This property applies only when the Output fields property is provided with any field value(s).

If this property is selected, the Snap tries to match the output data types same as when the Output fields property is empty (SELECT * FROM ...). The output preview would be in the same format as the one when SELECT * FROM is implied and all the contents of the table are displayed.

Default value: Not selected

Staging mode

Required when the value in the Number of retries field is greater than 0. 

Specify the location from the following options to store input documents between retries:

  • In memory: The query results are stored in the Snaplex memory. If the query is too large to fit in the memory space, it may cause the Snap to fail, choose the On disk option.
  • On disk: The query results are stored on the disk in a temporary (tmp) directory that is managed by the SnapLogic platform. This directory is deleted automatically when the Snap terminates.

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.

For the 'Suggest' in the Order by columns and the Output fields properties, the value of the Table name property should be an actual table name instead of an expression. If it is an expression, it will display an error message "Could not evaluate accessor:  ..." when the 'Suggest' button is clicked. This is because, at the time the "Suggest" button is clicked, the input document is not available for the Snap to evaluate the expression in the Table name property. The input document is available to the Snap only during the preview or execution time.

 

Snap Pack History

 Click to view/expand
Release Snap Pack VersionDateType  Updates
February 2024main25112 StableUpdated and certified against the current SnapLogic Platform release.
November 2023435patches23831 Latest

Fixed an issue with the PostgreSQL-Execute and PostgreSQL-Select Snaps that added escape characters ('\\') in the output for JSONB datatype.

November 2023main23721

 

StableUpdated and certified against the current SnapLogic Platform release.

August 2023

main22460

 


Stable

The PostgreSQL - Execute Snap now includes a new Query type field. When Auto is selected, the Snap tries to determine the query type automatically.

May 2023433patches21298 Latest

Fixed an issue with the PostgreSQL Insert Snap that inconsistently inserted some columns and missed the remaining columns(especially the Time fields), when the data was passed in the JSON format from an upstream Snap.

May 2023

main21015 

Stable

Upgraded with the latest SnapLogic Platform release.

February 2023 432patches20409 LatestThe PostgreSQL - Bulk Load and PostgreSQL - Insert Snaps no longer fail with the message ERROR: type modifier is not allowed for type 'bytea' when creating a new table if Create table if not present is selected and the target table does not exist. This issue occurred when metadata from the second input view document contained columns of the bytea data type.
February 2023 main19844 StableUpgraded with the latest SnapLogic Platform release.
November 2022

431patches19454

 Latest

The PostgreSQL Snap Pack supports geospatial data types.

November 2022main18944 Stable
  • The PostgreSQL - Bulk Load Snap can now process records with more than 16 KB in the document without encountering the BufferOverflowException because the default value of 16 KB for byte buffer size is now removed.
  • The PostgreSQL - Insert Snap now creates the target table only from the table metadata of the second input view when the following conditions are met:

    • The Create table if not present checkbox is selected.

    • The target table does not exist.

    • The table metadata is provided in the second input view.

September 2022430patches18149 Latest

The PostgreSQL Select and PostgresSQL Execute Snaps now read NaN values in Numeric columns when used with a PostgreSQL Account configured with the latest postgresql-42.5.0.jar driver.

September 2022430patches17894 Latest

The PostgreSQL Select Snap now works as expected when the table name is dependent on an upstream input.

August 2022430patches17700 LatestThe PostgreSQL - Bulk Load Snap can now process the records with more than 16KB in the document without encountering BufferOverflowException because the default value of 16KB for byte buffer size is now removed.
August 2022main17386 StableEnhanced the PostgreSQL Account and PostgreSQL Dynamic Account with SSH Tunneling configurations to encrypt the network connection between the client and the PostgreSQL Database server, thereby ensuring the secure network connection.
4.29 Patch429patches17036 Latest

Enhanced the PostgreSQL Account and PostgreSQL Dynamic Account with SSH Tunneling configurations to encrypt the network connection between the client and the PostgreSQL Database server, thereby ensuring a secure network connection.

4.29

main15993

 

Stable

Upgraded with the latest SnapLogic Platform release.

4.28main14627 StableUpdated the label for Delete Condition to Delete Condition (Truncates Table if empty) in the PostgreSQL Delete Snap.
4.27 Patch427patches13149 Latest

Fixed an issue with PostgreSQL - Execute Snap, where the Snap failed when using Delete query with the RETURNING function.

4.27main12833 Stable

Enhanced the PostgreSQL - Execute Snap to invoke stored procedures.

4.26main11181 StableUpgraded with the latest SnapLogic Platform release.
4.25 Patch425patches9879 Latest

Enhanced the performance of PostgreSQL - Bulk Load Snap significantly. SnapLogic anticipates that the Snap will execute up to 3 times faster than the previous version for enterprise workloads.

4.25main9554
 
StableUpgraded with the latest SnapLogic Platform release.
4.24main8556
Stable

Enhanced the PostgreSQL - 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. 

4.23main7430
 
StableUpgraded with the latest SnapLogic Platform release.

4.22 Patch

422patches6879 Latest

Fixed the PostgreSQL - Bulk Load Snap by preventing it from adding extra double quotes when loading values from input documents.

4.22main6403
 
StableUpgraded with the latest SnapLogic Platform release.
4.21 Patch421patches6272 Latest

Fixed 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.

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.
4.20snapsmrc535
 
StableUpgraded with the latest SnapLogic Platform release.
4.19 Patch db/postgres8409 Latest

Fixed an issue with the PostgreSQL - 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 new Snap PostgresSQL Bulk Load.

4.18 Patchpostgres8021 Latest

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

4.18snapsmrc523
 
StableUpgraded with the latest SnapLogic Platform release.
4.17 Patch db/postgres7588 Latest

Fixed an issue with tables sharing an overlapping column name wherein Pipeline execution fails due to the table collision.

4.17ALL7402
 
Latest

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

4.17snapsmrc515
 
Latest
  • Fixed an issue with the PostgreSQL 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/postgres6822 Latest

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
 
StableUpgraded with the latest SnapLogic Platform release.
4.15 Patch db/postgres6333 Latest

Replaced Max idle time and Idle connection test period properties with Max life time and Idle Timeout properties respectively, in the Account configuration. The new properties fix the connection release issues that were occurring due to default/restricted DB Account settings.

4.15snapsmrc500
 
StableUpgraded with the latest SnapLogic Platform release.
4.14snapsmrc490
 
Stable

Added support for Amazon Aurora and Azure SQL DB.

4.13

snapsmrc486

 
StableUpgraded with the latest SnapLogic Platform release.
4.12 PatchMULTIPLE4967 Latest

Provided an interim fix for an issue with the PostgreSQL 10 accounts by re-registering the driver for each account validation. The final fix is being shipped in a separate build.

4.12 Patch

postgres4832 Latest

Updated the driver from version 8.4.704 to version 9.4.1207 to support PostgreSQL v10 servers.

4.12

snapsmrc480

 
StableUpgraded with the latest SnapLogic Platform release.

4.11 Patch 

db/postgres4290 Latest

PostgreSQL Snap Pack - Fixed an issue when inserting a valid NaN value into a column.

4.11snapsmrc465
 
StableUpgraded with the latest SnapLogic Platform release.
4.10 Patchpostgres3773 Latest

Previously the Postgres PGObject datatype could not be serialized. It is now handled as a String.

4.10

snapsmrc414

 
Stable

Added Auto commit property to the Select and Execute Snaps at the Snap level to support overriding of the Auto commit property at the Account level.

4.9.0 Patchpostgres3134 Latest

PostgreSQL Execute: New Snap advanced property Auto commit has been implemented to fix the Select query error in PostgreSQL replica servers.

4.9 Patch

postgres3072 Latest

Fixed an issue regarding connection not closed after login failure; Expose autocommit for "Select into" statement in PostgreSQL Execute Snap and Redshift Execute Snap.

4.9snapsmrc405
 
StableUpgraded with the latest SnapLogic Platform release.
4.8.0 Patchpostgres2757 Latest

Potential fix for JDBC deadlock issue.

4.8.0 Patch

postgres2712 Latest

Fixed PostgreSQL Snap Pack rendering dates that are one hour off from the date returned by database query for non-UTC Snaplexes.

4.8.0 Patch

postgres2696

 


Latest

Addressed an issue where some changes made in the platform patch MRC294 to improve perfomance caused Snaps in the listed Snap Packs to fail.

4.8

snapsmrc398

 
Stable
  • Info tab added to accounts.
  • Database accounts now invalidate connection pools if account properties are modified and login attempts fail.
4.7.0 Patchpostgres2192 Latest

Fixed an issue for database Select Snaps regarding Limit rows not supporting an empty string from a pipeline parameter.

4.7.0 Patch

postgres2185 Latest

Resolved an issue with the PostgreSQL Execute Snap failing with a “java.util.regex.Pattern” error.

4.7

snapsmrc382

 
StableUpgraded with the latest SnapLogic Platform release.
4.6snapsmrc362
 
StableUpgraded with the latest SnapLogic Platform release.
4.5.1

postgres1584

 
Stable
  • Resolved an issue in the PostgreSQL - Execute Snap that resulted from restrictions on the 'with' operator in conjunction with an 'insert' statement.

  • Resolved an issue in the PostgreSQL Snaps that resulting from restrictions on the 'with' operator in conjunction with the RECURSIVE keyword.

4.4.1NA StableUpgraded with the latest SnapLogic Platform release.
4.4NA Stable
  • Resolved an issue with PostgreSQL Select Snap not parsing JSON data type correctly.
  • Note: The fix for this issue required updating libraries that impacted all database Snaps except those for MongoDB.
4.3.2NA Stable

This Snap Pack is now compatible with the PostgreSQL drivers available in 4.3 Patch mrc222.

NANA Stable
  • PostgreSQL Insert Snap: resolved an issue where it inserts a negative value when the input data was out of range.
  • PostgreSQL Snaps did not properly handle when a table name was created in mixed case.
  • JSON paths in WHERE clauses should be processed as bind values after the expression is evaluated.
NANA Stable
  • A - otd:6828 Postgres Snap shows wrong data type in preview for timestamp withtime zone data type
  • Dynamic DB queries now supported in the Execute Snap.
  • The SQL statement property now can be set as an expression property. When it is an expression, it will be evaluated with each input document and one SQL statement per each input document will be executed.
  • Known issue: When the SQL statement property is an expression, the pipeline parameters are shown in the suggest, but not the input schema.
  • With the SQL statement property set as an expression, the Snap can be exposed to SQL injection. Please use this feature with caution.
NANA Stable
  • PostgreSQL Insert: Enhanced data type support.
  • PostgreSQL Lookup: bug fixes on lookup failures; Pass-though on no lookup match property added to allow you to pass the input document through to the output view when there is no lookup matching.
    • PostgreSQL Select Snap: added support for handling array types.