ES hangs while indexing(very slow indexing)

I have an issue while indexing nested document(60-100MB) using python client.
I have the last elastic version.
The indexing is very slow and some times I got readTimeOut.
After the indexing process the whole index will hangs and searches will be slow as well, I tried to recreate the index but that doesn't help.
I have 5 machines in the cluster (without replicas), each machine with 32 GB RAM, i configured the memory heap size to be 16 GB and disabled the swapping.
I tried to use the hot_thread to see what is going on but I didn't see any thread with high CPU.

Indexing/updating/searching works nice with small documents before trying to index the big json (60-100MB) .

Does my mapping impact the indexing process?
Do I need to configure memory or something ?
What should I do ?


Documents of such excessive size are definitely not working with standard settings, risk of OOM and stalled nodes is high.

Have you tried to increase indices memory buffer?

Also, there is a 100mb limit on HTTP receive buffer which might be relevant