Indexing Accounts

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

🚀 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. 👓

Overview

Webchaind 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 webchaind is able to match accounts (by address) with their respective files. Webchaind also keeps a live sync of your /keystore directory, enabling you to add/change/remove files, with those changes reflected in realtime in webchaind. These conveniences and complications towebchainder -- 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 webchaind's use of accounts.db as its persistent cache instead of holding file indexes in memory.

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

Build an index

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

$ webchaind --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:

$ webchaind --index-accounts

toggles the persistent index option.

Maintain your index

All calls managing key files via webchaind 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