Basic Usage of python-rocksdb

Wrtie Batch

It is also possible to gather modifications and apply them in a single operation

update = pyrocksdb.WriteBatch()

# collect the operations
update.put(b'key1', b'value1')
update.put(b'key2', b'value2')
update.delete(b'key1')

opts = pyrocksdb.WriteOptions()
# Apply these operatios in a single operation
s = db.write(opts, update)

assert s.ok()
opts = pyrocksdb.ReadOptions()
blob = db.get(opts, b'key1')
assert blob.status.is_not_found()
blob = db.get(opts, b'key2')
assert blob.status.ok()
assert blob.data == b'value2'

db.close()

Iteration

Iterators behave slightly different than expected. Per default they are not valid. So you have to call one of its seek methods first

opts = pyrocksdb.WriteOptions()
s = {b'key1': b'value1', b'key2': b'value2', b'key3': b'value3'}
for k, v in s.items():
    db.put(opts, k, v)

opts = pyrocksdb.ReadOptions()
it = db.iterator(opts)
it.seek_to_first()
assert it.status().ok()
assert it.valid()
for k, v in s.items():
    assert it.key() == k
    assert it.value() == v
    it.next()

assert not it.valid()

it.seek(b'key1')
assert it.valid()
assert it.key() == b'key1'
assert it.value() == b'value1'
it.seek(b'key2')
assert it.valid()
assert it.key() == b'key2'
assert it.value() == b'value2'

it.seek(b'key4')
assert not it.valid()

it.seek_for_prev(b'key0')
assert not it.valid()
it.seek_for_prev(b'key4')
assert it.valid()