Tune RocksDB memory usage

[teor2345]

Analysis

We think RocksDB is the major Zebra memory user.

Here is the RocksDB memory tuning guide:
https://github.com/facebook/rocksdb/wiki/Memory-usage-in-RocksDB

We probably want to add sprout and sapling anchors, and finish transaction validation, before we try to tune memory. Those changes will increase the database size, and change data access patterns.

Unbounded block queues can also use a lot of memory, see #1389

Version

v1.0.0-alpha.0

Platform

Unknown

Description

Zebra uses 4.3 GB, but zcashd uses 1.5 GB of RAM.

[rex4539]

I would argue that zebrad uses less memory than zcashd.

[teor2345]

zebrad and zcashd memory usage will depend on:

• what they are each doing at the time they are measured
• how they are each configured
• network speed
• open files limit (changes RocksDB memory usage)
• the OS
• debug/release builds
• missing checks and features in Zebra

So different users will probably get different measurements.

[mpguerra]

Do we want to investigate this further or close it out for now?

[teor2345]

We probably want to add sprout and sapling anchors, and finish transaction validation, before we try to tune memory. Those changes will increase the database size, and change data access patterns.

I don't think we can do anything about this issue right now.

[teor2345]

PR #1523 will help us monitor Zebra's memory usage over time, in a consistent environment.