Indexing Accounts

ia edited this page Jun 7, 2017 · 6 revisions

Indexing Accounts

If you're handling a large number of files (~10k -> ~100k+, depending on your system capacities) it becomes advantageous for geth to implement persistent indexing of the key files.

:rocket: This feature relatively young -- having only been included in 3.5.0 -- and we'll be very happy to hear your feedback if you've taken advantage of it. :eyeglasses:

Overview

Geth allows for a large amount of leniency in managing and interacting with key files. For example, you can have a keyfile named "foobar.md", and that's just fine. The downside of this is that it presents some inefficiencies in how geth is able to match accounts (by address) with their respective files. Geth also keeps a live sync of your /keystore directory, enabling you to add/change/remove files, with those changes reflected in realtime in geth. These conveniences and complications together -- combined with the innate awkwardness of handling a large number of small files (try running ls -l for a directory with 500k files) -- present a hurdle when the number of key files grows to a high number.

The solutions which persistent indexing uses to address these problems are

  • disable FS watching and live reload, and
  • establish geth's use of accounts.db as its persistent cache instead of holding file indexes in memory.

Instead of asking geth to re-index and store all key files each time a geth instance is started, it'll instead connect with a lightweight key-value store in /keystore/accounts.db.

Build an index

Before running geth with the indexed accounts option, you'll first need to build the index. Run:

$ geth --verbosity 5 --index-accounts account index

to create an index store (accounts.db). The --verbosity flag in this example is optional, but may be desirable for monitoring progress.

You may additionally use --data-dir, --chain, and --keystore flags to specify custom base data directory, chain subdirectory, and keystore directory as well.

Run with persistent indexed accounts

Once you've built an index, running:

$ geth --index-accounts

toggles the persistent index option.

Maintain your index

All calls managing key files via geth API/RPC/CLI will be automatically updated and persisted in the index file. However, if you make outside changes to your key files, those changes will not be synced to the index. In this case, rebuilding your index -- with the exact same command as setup) -- will suffice to to update the index with those changes.

Benchmarks

All measurements in nanoseconds/operation with watching disabled on *2.8 GHz Intel Core 2 Duo @ 8GB RAM.

Create, Update, Sign, and Delete a new account

This tests a bundled general suite of four interactions without querying. Here, in-memory is king, because the test essentially measures manipulations from memory vs. disk i/o. While persistent storage takes significantly more time (as high as 0.24 seconds for the suite), it's also worth noting that both rates behave approximately constantly across every tested number of key files.

Number of Accounts In-memory caching Persistent caching
100 29147464 88912525
500 58596449 144582028
1000 32701806 203180542
5000 33743063 74667460
10000 24605203 133318754
20000 26082395 92159681
100000 21709988 168614805
200000 22346704 249697976
500000 39045149 161666411

Sign a key given address and passphrase

This tests a commonly used key transaction for a pre-existing key file/account. Here's where the payoff for persistent indexing comes; persisted key indexes must never be sorted or parsed entirely.

Number of Accounts In-memory caching Persistent caching
100 2963462 2923034
500 2892381 2871620
1000 5049611 3070000
5000 5862756 3035130
10000 5824062 3328642
20000 724523342 2990753
100000 356307574244 3314435
200000 DNF 5204148
500000 DNF 3114311
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