Purpose

Provide you with a brief introduction to some of the important technical aspects of Mango v3 program. This doc is at an intermediate level so if you want a more basic intro to solana programming, check out the links section below. This doc will only help familiarize you with concepts so reading the code is a bit easier. There is no substitute for actually reading the code: https://github.com/blockworks-foundation/mango-v3.

Table of Contents

State Accounts

There are a few major Solana Accounts that you will encounter frequently.

MangoGroup

• Holds broad market info about tokens, Serum DEX markets, Perp markets, oracles, insurance fund, fees vaults
• This account is passed in as read-only in most instructions so transactions may be parallelized

MangoAccount

• A user's MangoAccount keeping track of their deposits, borrows and PerpAccount for each perp market.

MangoCache

• Solana txs are limited to 1200 bytes in tx data. As a result, only ~35 accounts may be passed in any tx. This limitation would prevent us from cross margining as many tokens. To get around this, the MangoCache contains important bits of information aggregated across several different accounts into one account.
• MangoCache holds PriceCache, RootBankCache, PerpMarketCache
• The Cache is always used for consistency instead of the raw value even if the raw value is available in a transaction

PerpMarket

• Contains PerpMarket related info (e.g. lot sizes, liquidity mining information)
• Funding is kept track through an O(1) mechanism on the PerpMarket
  • long_funding variable goes up when the book price is above the index price.
  • The long_settled_funding on each MangoAccount keeps track of the last time the user settled funding. At the start, the long_settled_funding will equal long_funding on the cache. The difference between the long_funding and the long_settled_funding is the funding per contract the MangoAccount owes.