The 21st century can be the era of Big Data. Huge databases are generated by different scientific projects, industry and society in general. In the particular case of Astronomy, both ground (SKA, ALMA, SDSS, LSST, etc) and space telescopes (HST, Chandra, Spitzer, etc), as well as Astronomical Numerical Simulations (Millennium Simulation project, IllustrisTNG project, etc) are developed in supercomputers and generate databases of tens or hundreds of petabytes. To manipulate these databases, different data mining algorithms and specialized software for data analysis are used. In the case of numerical simulations data can be manipulated in two ways: first, the database is generated and then analyzed, or in-situ data analysis is done, i.e., data is analyzed as it is generated. In this presentation I will discuss the two possibilities for data analysis.