Previously freezer has only been used for storing ancient chain data, while obviously it can be used more. This PR unties the chain data and freezer, keep the minimal freezer structure and move all other logic (like incrementally freezing block data) into a separate structure called ChainFreezer.
This PR also extends the database interface by adding a new ancient store function AncientDatadir which can return the root directory of ancient store. The ancient root directory can be used when we want to open some other ancient-stores (e.g. reverse diff freezer).
* core/rawdb, cmd, ethdb, eth: implement freezer tail deletion
* core/rawdb: address comments from martin and sina
* core/rawdb: fixes cornercase in tail deletion
* core/rawdb: separate metadata into a standalone file
* core/rawdb: remove unused code
* core/rawdb: add random test
* core/rawdb: polish code
* core/rawdb: fsync meta file before manipulating the index
* core/rawdb: fix typo
* core/rawdb: address comments
This change is a rewrite of the freezer code.
When writing ancient chain data to the freezer, the previous version first encoded each
individual item to a temporary buffer, then wrote the buffer. For small item sizes (for
example, in the block hash freezer table), this strategy causes a lot of system calls for
writing tiny chunks of data. It also allocated a lot of temporary []byte buffers.
In the new version, we instead encode multiple items into a re-useable batch buffer, which
is then written to the file all at once. This avoids performing a system call for every
inserted item.
To make the internal batching work, the ancient database API had to be changed. While
integrating this new API in BlockChain.InsertReceiptChain, additional optimizations were
also added there.
Co-authored-by: Felix Lange <fjl@twurst.com>
