title: Why does my google colab session keep crashing?
body: <p>I am using google colab on a dataset with 4 million rows and 29 columns. When I run the statement sns.heatmap(dataset.isnull()) it runs for some time but after a while the session crashes and the instance restarts. It has been happening a lot and I till now haven't really seen an output. What can be the possible reason ? Is the data/calculation too much ? What can I do ?</p>