(EDITED)
List of implementation changes:
- new database layout:
- 2 leveldb's (coins/ and blktree/ subdirs), replacing blkindex.dat
- separate directory (blocks/) with block data (in the usual format, but smaller files) and undo data
- database keys are of the form (char,key) instead of (string,key) for reasons of compactness
- there is no txid-to-diskpos index anymore, only blkid-to-diskpos and txid-to-unspent-outputs
- this makes getrawtransaction only work on unspent outputs (and slower)
- an optional txid-to-diskpos index is planned
- this makes getrawtransaction only work on unspent outputs (and slower)
- some new very specialized serializers are added (compact variable-length integer, compact amount, compact txout)
- block index does not store hashBlockNext anymore - this is reconstructed from hashBestBlock at startup
- at startup, automatically reorg to the best block in blktree/blocks
- new RPCs: gettxoutsetinfo and gettxout operate on the coins database
- no more CTxIndex in-scope: instead, a global pcoinsTip (representing the coin db) and pblocktree (representing the blktree db)
- intended to be moved to separate modules/classes, properly encapsulated
- blktree database contains statistics about the block file (size, which blocks in it, times, heights, undo stats, ...)
- blktree database contains flag per block that determines the degree of validation it had, to allow future headers-first mode
- block files are pre-allocated (in batches of 16 MiB, the files grow to max 128 MIB), to reduce fragmentation
- transaction hashes are cached, and typically never calculated more than once
Included in the pullreq, but technically separate:
- do -loadblock= and bootstrap.dat import in a separate thread
- add check for strict DER encoding for signatures, and standard public keys
Originally posted by @sipa in #1677 (comment)
Hello, is there any formula or performance tests to choose the size of 128 MB as chunksize in blk*.data files?
