https://github.com/benoitc/memdb
Erlang memory backend K/V store
https://github.com/benoitc/memdb
Last synced: 11 months ago
JSON representation
Erlang memory backend K/V store
- Host: GitHub
- URL: https://github.com/benoitc/memdb
- Owner: benoitc
- License: mpl-2.0
- Created: 2015-12-20T19:11:45.000Z (about 10 years ago)
- Default Branch: master
- Last Pushed: 2015-12-20T22:27:15.000Z (about 10 years ago)
- Last Synced: 2025-04-09T10:07:22.142Z (11 months ago)
- Language: Erlang
- Size: 62.5 KB
- Stars: 10
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# memdb - provides a memory-backed K/V store #
Copyright (c) 2015 Benoît Chesneau.
__Version:__ 0.1.0.
# memdb: simple memory database
memdb is K/V store built on top of [ETS](http://www.erlang.org/doc/man/ets.html). memdb compared to ETS provides
concurrent access to the database using [MVCC](https://en.wikipedia.org/wiki/Multiversion_concurrency_control) allowing
multiple reader to read concurrently a consitent view of the database without locking.
All writes are serialized for now.
A MemDB's memory consumption increases monotonically, even if keys are deleted or values are updated. Compaction can be
triggered manually or automatically using the auto-vacuum. A full snapshot can be stored or copied in another database
if needed.
## Documentation
Full doc is available in the [`memdb`](memdb.md) module.
## Usage:
------
'''
### Create a database:
```
Db = memdb:open(Name).
```
### Store a values
Storing a value associated to a key using `memdb:put/3`:
```
Key = <<"a">>,
Value = 1,
ok = memdb:put(Key, Value, Db).
```
### Retrieve a value
Use the `memdb:get/2` function to retrieve a value.
```
Value = memdb:get(Key, Db).
```
Value should be 1
> Note: you can use `memdb:contains/2`.
### Delete a value
Use `memdb:delete/2` to delete a value:
```
ok = memdb:clear(Ke, Dby).
```
### Store and write multiples values in one pass:
Using `memdb:write_batch/2` you can write and delete multiple values in one
pass:
```
ok = memdb:write_batch([{put, <<"a">>, 1},
lput, <<"b">>, 2},
{put, <<"c">>, 3}], Db),
ok = memdb:write_batch([{put, <<"d">>, 4},
{delete, <<"b">>},
{put, <<"e">>, 5}], Db).
```
### Retrieve multiple values in a range:
Use `memdb:fold/4` to retrieve multiples K/Vs
### Close a storage
Close a storage using `memdb:close/1`:
```
memdb:close(Engine)
```
## Build
```
$ make
```
## Modules ##