def _compact_hashX(self, hashX, hist_map, hist_list, write_items,
keys_to_delete):
"""Compress history for a hashX. hist_list is an ordered list of
the histories to be compressed."""
# History entries (tx numbers) are 4 bytes each. Distribute
# over rows of up to 50KB in size. A fixed row size means
# future compactions will not need to update the first N - 1
# rows.
max_row_size = self.max_hist_row_entries * 4
full_hist = b''.join(hist_list)
nrows = (len(full_hist) + max_row_size - 1) // max_row_size
if nrows > 4:
self.logger.info('hashX {} is large: {:,d} entries across '
'{:,d} rows'.format(hash_to_hex_str(hashX),
len(full_hist) // 4, nrows))
# Find what history needs to be written, and what keys need to
# be deleted. Start by assuming all keys are to be deleted,
# and then remove those that are the same on-disk as when
# compacted.
write_size = 0
keys_to_delete.update(hist_map)
for n, chunk in enumerate(util.chunks(full_hist, max_row_size)):
key = hashX + pack_be_uint16(n)
if hist_map.get(key) == chunk:
keys_to_delete.remove(key)
else:
write_items.append((key, chunk))
write_size += len(chunk)
assert n + 1 == nrows
self.comp_flush_count = max(self.comp_flush_count, n)
return write_size
def _compact_history(self, limit):
"""Inner loop of history compaction. Loops until limit bytes have
been processed.
"""
keys_to_delete = set()
write_items = [] # A list of (key, value) pairs
write_size = 0
# Loop over 2-byte prefixes
cursor = self.comp_cursor
while write_size < limit and cursor < 65536:
prefix = pack_be_uint16(cursor)
write_size += self._compact_prefix(prefix, write_items,
keys_to_delete)
cursor += 1
max_rows = self.comp_flush_count + 1
self._flush_compaction(cursor, write_items, keys_to_delete)
self.logger.info(
'history compaction: wrote {:,d} rows ({:.1f} MB), '
'removed {:,d} rows, largest: {:,d}, {:.1f}% complete'.format(
len(write_items), write_size / 1000000, len(keys_to_delete),
max_rows, 100 * cursor / 65536))
return write_size
def flush(self):
start_time = time.time()
self.flush_count += 1
flush_id = pack_be_uint16(self.flush_count)
unflushed = self.unflushed
with self.db.write_batch() as batch:
for hashX in sorted(unflushed):
key = hashX + flush_id
batch.put(key, unflushed[hashX].tobytes())
self.write_state(batch)
count = len(unflushed)
unflushed.clear()
self.unflushed_count = 0
if self.db.for_sync:
elapsed = time.time() - start_time
self.logger.info(f'flushed history in {elapsed:.1f}s '
f'for {count:,d} addrs')