tHashInput and tHashOutput components are not directly accessible. To make them accessible, we need to modify the project properties.
I have several questions :
1) Why aren't these components accessible from the start ?
2) I usually use CSV files to transfer data between sub-jobs and save these data in case of errors, etc. Could I use tHash components instead (let's assume that I don't want to store this data on the disk) ?
3) The cache memory is limited, so are these components recommended ?
By default, the technical components tHashInput and tHashOutput (and some other components) are not visible in the Palette. This is expected and it is a design behavior as described in the Talend Studio Component Reference Guide, Technical Components section.
For more information, please have a look at this documentation:
For question 2 and question 3, It depends on your job requirement and the point of using thashinput/tHashInput is to store the result of the first Subjob (input) in memory (cache).
You'd better store temporary data on disk rather than in memory if you are using a large amount of data, as buffer components will consume a large amount of memory. This will optimize our job performance and avoid OutOfMemory Exception.
