Decode "timestamp" from oplog.timestamp

On the wiki it says: The exact format of this file depends on MongoDB’s toplogy. For a single replica set, the format is:

["oplog name", timestamp]

An example would be:

["Collection(Database(MongoClient('localhost', 27017), u'local'), u'oplog.rs')", 6185588281674039941]

What format is this timestamp in, and how do you convert say, 6185588281674039941, to a normal date?

Thanks.

[howardkhl]

Okay, found a solution for this.

util.py has a method long_to_bson_ts, use Python to run the method directly:

python -c 'import util; print util.long_to_bson_ts(<val>)'

For example:

python -c 'import util; print util.long_to_bson_ts(6185145118358503425)'

And you will get a Timestamp object back.

Timestamp(1440091319, 1)

In python, use datetime to convert Timestamp to human readable form:

python
>>> from datetime import datetime
>>> str(datetime.fromtimestamp(1440091319))

It will return:

'2015-08-20 10:21:59'

For comparison purpose, this command will return current system time:

>>> str(datetime.now())

[howardkhl]

Update, I’ve tried the following on my mac terminal and no dependencies issue. Convert from Epoch time to bson format (oplog) and vice versa.

https://atharva-inamdar.medium.com/understanding-mongodb-oplog-249f3996f528

1. Install pymongo pip install pymongo
2. In Python3 terminal python3
3. Copy paste:

from bson import Timestamp
from datetime import datetime
def ts_to_int(ts):
  return (ts.time << 32) + ts.inc
def int_to_ts(t):
  return Timestamp(t>>32, t & (2**32)-1)

1. Try it out:

>>> ts=Timestamp(datetime.utcnow(), 1)
>>> print(ts_to_int(ts))
7052809609722986497
>>> ts=Timestamp(1642100404, 1)
>>> print(ts_to_int(ts))
7052767531928387585