On Thu, Jun 23, 2011 at 9:51 PM,
<jan@uos.de> wrote:
Hi there!
Instawallet has enjoyed steady growth and I'm running into a bottleneck
now with "getbalance <someaccounthere>" taking quite some time to
complete. My understanding is, that this is because bitcoind runs
through all relevant transactions each time anew to compute the balance.
I was hoping the list could give me some pointers/ideas on how I can
improve this.
I think the easiest way to speed this up would be to scan the wallet
every time a block comes in or something else changes in the block chain
(or, if you prefer, some pre-set interval of N minutes). Then go over
the entire wallet and the accumulate balances for all accounts. This could
be done in amortized linear time using a hash_map.
1) This reduces the time the API takes to return the balance for an account to a predictable, very short time. Just the time to look up the balance in the hash table (and return 0 on miss). The number crunching happens in the network thread, not while you're waiting on the API.
2) Less bug-prone than "incremental caching" as you propose, and
doesn't require determining which accounts are influenced by a new block
3) Block chain reorgs are no problem.
JS