Provided by: python-pmemkv-doc_1.0-4build1_all 
NAME
pmemkv-python - pmemkv-python 1.0
PMEMKV PACKAGE
Python bindings for pmemkv
pmemkv is a local/embedded key-value datastore optimized for persistent memory. For more information,
see https://pmem.io/pmemkv.
Submodules
pmemkv.pmemkv module
Python bindings for pmemkv.
class pmemkv.pmemkv.Database(engine, config)
Bases: object
Main Python pmemkv class, it provides functions to operate on data in database.
This class can be used dict-like, i.a. accessing and assigning data using ‘[]’. If an
error/exception is thrown from any method it will contain pmemkv’s status and error message.
Currently returned statuses are described in libpmemkv manpage:
https://pmem.io/pmemkv/master/manpages/libpmemkv.3.html#errors
Possible exceptions to be thrown in Python binding are as follows: - Error, - UnknownError, -
NotSupported, - InvalidArgument, - ConfigParsingError, - ConfigTypeError, - StoppedByCallback, -
WrongEngineName, - TransactionScopeError.
__init__(engine, config)
Parameters
• engine (str) – Name of the engine to work with.
• config (dict) – Dictionary with parameters specified for the engine. Required
configuration parameters are dependent on particular engine. For more information
on engine configuration please look into pmemkv man pages.
count_above(key)
Returns number of currently stored key/value pairs in the pmemkv datastore, whose keys are
greater than the given key.
Parameters
key (str) – Sets the lower bound for querying.
Returns
number – Number of key/value pairs in the datastore, whose keys are greater than the
given key.
Return type
int
count_all()
Returns number of currently stored key/value pairs in the pmemkv datastore.
Returns
number – Total number of elements in the datastore.
Return type
int
count_below(key)
Returns number of currently stored key/value pairs in the pmemkv datastore, whose keys are
less than the given key.
Parameters
key (str) – Sets the upper bound for querying.
Returns
number – Number of key/value pairs in the datastore, whose keys are lower than the
given key.
Return type
int
count_between(key1, key2)
Returns number of currently stored key/value pairs in the pmemkv datastore, whose keys are
greater than the key1 and less than the key2.
Parameters
• key1 (str) – Sets the lower bound for querying.
• key2 (str) – Sets the upper bound for querying.
Returns
number – Number of key/value pairs in the datastore, between given keys.
Return type
int
exists(key)
Verifies the presence key/value pair in the pmemkv datastore.
Parameters
key (str) – key to query for.
Returns
exists – true if element with given key exists in the datastore, false if not.
Return type
bool
get(key, func)
Executes callback function for value for given key.
Parameters
• key (str) – key to query for.
• func (function (may be lambda)) – Function to be called for specified key/value
pair. Value passed to func is read-only buffer and may be accessed by memoryview
function. Callback function should accept one positional argument, which is
value. Please notice, key is not passed to callback function. For more
information please look into Buffer Protocol documentation.
get_above(key, func)
Executes callback function for every key/value pair stored in the pmemkv datastore, whose
keys are greater than the given key.
Parameters
• key (str) – Sets the lower bound for querying.
• func (function (may be lambda)) – Function to be called for each specified
key/value pair. Key and value passed to func are read-only buffers and may be
accessed by memoryview function. Callback function should accept two positional
arguments, which are key and value. For more information please look into Buffer
Protocol documentation.
get_all(func)
Executes callback function for every key/value pair stored in the pmemkv datastore.
Parameters
func (function (may be lambda)) – Function to be called for each key/value pair in
the datastore. Key and value passed to func are read-only buffers and may be
accessed by memoryview function. Callback function should accept two positional
arguments, which are key and value. For more information please look into Buffer
Protocol documentation.
get_below(key, func)
Executes callback function for every key/value pair stored in the pmemkv datastore, whose
keys are lower than the given key.
Parameters
• key (str) – Sets the upper bound for querying.
• func (function (may be lambda)) – Function to be called for each specified
key/value pair. Key and value passed to func are read-only buffers and may be
accessed by memoryview function. Callback function should accept two positional
arguments, which are key and value. For more information please look into Buffer
Protocol documentation.
get_between(key1, key2, func)
Executes callback function for every key/value pair stored in the pmemkv datastore, whose
keys are greater than the key1 and less than the key2.
Parameters
• key1 (str) – Sets the lower bound for querying.
• key2 (str) – Sets the upper bound for querying.
• func (function (may be lambda)) – Function to be called for each specified
key/value pair. Key and value passed to func are read-only buffers and may be
accessed by memoryview function. Callback function should accept two positional
arguments, which are key and value. For more information please look into Buffer
Protocol documentation.
get_keys(func)
Executes callback function for every key stored in the pmemkv datastore.
Parameters
func (function (may be lambda)) – Function to be called for each key. Key passed to
func is read-only buffer and may be accessed by memoryview function. Callback
function should accept one positional argument, which is key. For more information
please look into Buffer Protocol documentation.
get_keys_above(key, func)
Executes callback function for every key stored in the pmemkv datastore, whose keys are
greater than the given key.
Parameters
• key (str or byte-like object) – Sets the lower bound for querying.
• func (function (may be lambda)) – Function to be called for each key above one
specified in key parameter. Key passed to func is read-only buffer and may be
accessed by memoryview function. Callback function should accept one positional
argument, which is key. For more information please look into Buffer Protocol
documentation.
get_keys_below(key, func)
Executes callback function for every key stored in the pmemkv datastore, whose keys are
lower than the given key.
Parameters
• key (str or byte-like object) – Sets the upper bound for querying.
• func (function (may be lambda)) – Function to be called for each key below one
specified in key parameter. Key passed to func is read-only buffer and may be
accessed by memoryview function. Callback function should accept one positional
argument, which is key. For more information please look into Buffer Protocol
documentation.
get_keys_between(key1, key2, func)
Executes callback function for every key stored in pmemkv datastore, whose keys are greater
than the key1 and less than the key2.
Parameters
• key1 (str or byte-like object) – Sets the lower bound for querying.
• key2 (str) – Sets the upper bound for querying.
• func (function (may be lambda)) – Function to be called for each key between key1
and key2. Key passed to func is read-only buffer and may be accessed by memoryview
function. Callback function should accept one positional argument, which is key.
For more information please look into Buffer Protocol documentation.
get_string(key)
Gets copy (as a string) of value for given key.
Value returned by get_string() is still accessible after removal of element from datastore.
Parameters
key (str) – key to query for.
Returns
value – Copy of value associated with the given key.
Return type
str or byte-like object
put(key, value)
Inserts the key/value pair into the pmemkv datastore. This method accepts Unicode objects
as well as bytes-like objects. Unicode objects are stored using ‘utf-8’ encoding.
Parameters
• key (str or byte-like object) – record’s key; record will be put into database
under its name.
• value (str or byte-like object) – data to be inserted into this new datastore
record.
remove(key)
Removes key/value pair from the pmemkv datastore for given key.
Parameters
key (str) – Record’s key to query for, to be removed.
Returns
removed – true if element was removed, false if element didn’t exist before removal.
Return type
bool
stop() Stops the running engine.
Readme file can be found here.
• genindex
• modindex
• search
AUTHOR
Intel Corporation
COPYRIGHT
2022, Intel Corporation
1.0 Mar 17, 2022 PMEMKV-PYTHON(1)