Unhide/Hide components (tHashoutput/tHashInput) in talend open studio

Unhide/Hide components (tHashoutput/tHashInput) in talend open studio


In this blog i will talk about how to unhide tHashoutput/tHashInput components in your talend studio. These components are useful to store data in memory in your talend job and read it across the same talend job.


By default some components are hidden in your talend opend studio. Two such components are tHashOutput and tHashInput. tHashOutput is used to store data in your job in memory. tHashInput is used to read the data stored in tHashOutput map and emit this data like other input components. These components becomes very handy when you want to do some trnasformation in data in memory. A point to note is that the memory required by the JVM when your job runs depends on the amount of data you want to store in memory/tHashOutput. The read and write of data using tHash components is fast but it consumes your memory. Writing to tHashOutput and reading from tHashInput is nothing different from other standard output and input components of talend. You need to define the schema for these components and connect flow from/to other components to/from these.

Enabling tHashoutput/tHashInput

By default these components are hidden in talend open studio.
To enable these go to File Menu–>Edit project properties–>PaletteSettings.
Here you can see components inside their folders – Technical is the folder which contains tHash* components. You can make this folder or components visible by bringing them to Show section of dialogbox and applying changes. I have brought tHashInput and tHashoutput to show section below. Like this you can see there are other hidden components too and you can enable them also along with tHash components.

By default theses components are hidden.


We can move them to available (not hidden) section along with other components. Just refresh your studio and you should be able to see all components.

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