Could not keep it under the rug until April Fool’s Day
TigerBeetle is a reliable, fast, and highly available database for financial accounting. It tracks financial transactions or anything else that can be expressed as double-entry bookkeeping, providing three orders of magnitude more performance and guaranteeing durability even in the face of network, machine, and storage faults.
Continuing my if all you have is a hammer, everything looks like a nail journey, I wanted to store arbitrary binary blobs in TigerBeetle to protect them from storage faults. If I can do that, I can store anything.
The id field of my Accounts will contain the filename (16-byte limit). I will store the total file size in the user_data_64 field and the filename length in the user_data_32 field (to simplify decoding). And my Accounts will have this nice property that credits_posted will contain the actual number of bytes written. I can detect failed uploads and resume upload from the right offset (a future TODO).
def create_a_file(filename, size):
if len(filename) > 16:
raise ValueError("Invalid filename, more than 16 bytes")
account = tb.Account(
id=int.from_bytes(filename.encode()),
user_data_64=size,
user_data_32=len(filename),
ledger=FILE,
code=FILE,
)
errors = client.create_accounts([account])
if errors:
raise ValueError(errors[0])
return account
What makes me unhappy is that I have not found a good use for the user_data_128 field on the Account record. Such a waste of resources!
I will store the actual bytes in Transfer user_data_128, user_data_64, and user_data_32 fields. That gives a total of 28 bytes per Transfer, and the Transfer amount will contain the number of bytes used in the Transfer. Which will be 28 for all Transfers except the last one containing the remaining bytes.
transfers.append(
tb.Transfer(
id=tb.id(),
debit_account_id=system_id,
credit_account_id=file_id,
amount=len(block),
user_data_128=int.from_bytes(block[:16]),
user_data_64=int.from_bytes(block[16:24]),
user_data_32=int.from_bytes(block[24:]),
ledger=FILE,
code=FILE,
)
)
Because TigerBeetle uses double-entry bookkeeping, I will transfer all bytes from a system file “.” (debit side) to the desired file (credit side). Which is extremely useful for audit purposes to verify that debits_posted on the system file Account is the same as credits_posted on all file Account records.
As for getting data out of TigerBeetle, I can retrieve all credit Transfers for the specific Account. They are always correctly ordered by the timestamp field as guaranteed by the TigerBeetle.
timestamp_min = 0
while True:
transfers = client.get_account_transfers(
tb.AccountFilter(
account_id=file_id, flags=tb.AccountFilterFlags.CREDITS, limit=BULK, timestamp_min=timestamp_min
)
)
for transfer in transfers:
timestamp_min = transfer.timestamp
...
if len(transfers) < BULK:
break
timestamp_min += 1
All that put together, I performed tests on some of the most valuable files I did not want to ever loose:
(venv) du -b ~/Downloads/homework.mp4
104718755 /home/aivarsk/Downloads/homework.mp4
(venv) time ./tbcp ~/Downloads/homework.mp4 tb:backup.mp4
real 2m3.697s
user 1m4.408s
sys 0m1.568s
So, you can store your files durably at speeds close to 642 kB/s. Now, let’s retrieve the file and store it on the disk:
(venv) time ./tbcp tb:backup.mp4 copy.mp4
real 0m47.588s
user 0m27.027s
sys 0m0.553s
Downloading is around four times faster at 2,228 kB/s! And of course, I verified that not a single bit was lost during the round-trip:
(venv) sha256sum ~/Downloads/homework.mp4
4ee75486c7c65a5c158f7f6b2ca6458195aa25b155b0688173b4b52583ce4cac /home/aivarsk/Downloads/homework.mp4
(venv) sha256sum copy.mp4
4ee75486c7c65a5c158f7f6b2ca6458195aa25b155b0688173b4b52583ce4cac copy.mp4
(venv)
If you want to store your valuable files, guaranteeing durability even in the face of network, machine, and storage faults, here is the full source code