# tHashInput

Reads from the cache memory data loaded by tHashOutput to offer high-speed data feed, facilitating transactions involving a large amount of data.

The components of the Technical family are normally hidden from the Palette by default. For more information about how to show them on the Palette, see [Palette settings](https://help.qlik.com/talend/r/en-US/8.0/studio-user-guide/palette-settings).

Information noteNote: This component cannot be used in ESB use cases.

## tHashInput Standard properties

These properties are used to configure tHashInput running in the Standard Job framework.

The Standard tHashInput component belongs to the Technical family.

The component in this framework is available in all Talend products.

## Basic settings

| Properties | Description |
| --- | --- |
| Schema and Edit<br>schema | <ul> <li> <p>A schema is a row description, it defines the number of fields to                                be processed and passed on to the next component. The schema is                                either built-in or remotely stored in the Repository. </p> <p>Click <span>Edit        schema</span> to make changes to the schema. If the current schema is of the <span>Repository</span> type, three options are available:</p> <ul> <li> <p> <span>View schema</span>: choose this                option to view the schema only.</p> </li> <li> <p> <span>Change to built-in property</span>:                choose this option to change the schema to <span>Built-in</span> for local changes.</p> </li> <li> <p> <span>Update repository connection</span>:                choose this option to change the schema stored in the repository and decide whether                to propagate the changes to all the Jobs upon completion.</p> <p>If you just want to                propagate the changes to the current Job, you can select <span>No</span> upon completion and choose this schema metadata                again in the <span>Repository Content</span>                window.</p> </li> </ul> <p>This component offers the advantage of the                  dynamic schema feature. This allows you to retrieve unknown columns from source                  files or to copy batches of columns from a source without mapping each column                  individually. For further information about dynamic schemas, see <a href="https://help.qlik.com/talend/r/en-US/8.0/studio-user-guide/dynamic-schema" target="_blank">Dynamic schema</a>.</p> <p>This            dynamic schema feature is designed for the purpose of retrieving unknown columns of a            table and is recommended to be used for this purpose only; it is not recommended for the            use of creating tables.</p> </li> <li> <p> <span>Built-in</span>: The schema is created                                and stored locally for this component only. For more information about a component schema in its <span>Basic settings</span> tab, see <a href="https://help.qlik.com/talend/r/en-US/8.0/studio-user-guide/basic-settings-tab" target="_blank">Basic settings tab</a>. </p> </li> <li> <p> <span>Repository</span>: The schema already                                exists and is stored in the Repository, hence can be reused. For more information about a component schema in its <span>Basic settings</span> tab, see <a href="https://help.qlik.com/talend/r/en-US/8.0/studio-user-guide/basic-settings-tab" target="_blank">Basic settings tab</a>. </p> </li> </ul> |
| Link with a tHashOutput | Select this check box to connect to a tHashOutput component. It is always selected by<br>default. |
| Component list | Drop-down list of available tHashOutput components. |
| Clear cache after reading | Select this check box to clear the cache after reading the data<br>loaded by a certain tHashOutput<br>component. This way, the following tHashInput components, if any, will not be able to<br>read the cached data loaded by that tHashOutput component. |

## Advanced settings

| Properties | Description |
| --- | --- |
| tStatCatcher Statistics | Select this check box to collect log data at the component<br>level. |

## Global Variables

| Variables | Description |
| --- | --- |
| Global Variables | ERROR\_MESSAGE: the error message generated by the<br>component when an error occurs. This is an After variable and it returns a string. This<br>variable functions only if the Die on error checkbox is<br>cleared, if the component has this checkbox.<br><br><br>NB\_LINE:<br>the number of rows processed. This is an After variable and it returns an integer.<br><br>A Flow variable functions during the execution of a component<br>while an After variable functions after the execution of the component.<br><br>To fill up a field or expression with a variable, press Ctrl+Space to access the variable list and choose the variable to use from<br>it.<br><br>For more information about variables, see [Using contexts and variables](https://help.qlik.com/talend/r/en-US/8.0/studio-user-guide/contexts-and-variables). |

## Usage

| Usage guidance | Description |
| --- | --- |
| **Usage rule** | This component is used along with tHashOutput. It reads from the cache memory data<br>loaded by tHashOutput. Together,<br>these twin components offer high-speed data access to facilitate<br>transactions involving a massive amount of data. |

**Related concepts**

* [Clearing the memory before loading data to it in case an iterator exists in the same subJob](https://help.qlik.com/talend/en-US/components/8.0/technical/thashoutput-thashinput-tfixedflowinput-tlogrow-clearing-memory-before-loading-data-to-it-in-case-iterator-exists-in-same-subjob-standard-component-in-this)
* [Reading data from the cache memory for high-speed data access](https://help.qlik.com/talend/en-US/components/8.0/technical/thashoutput-thashinput-tfixedflowinput-tfileoutputdelimited-reading-data-from-cache-memory-for-high-speed-data-access-standard-component-the)