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python bingding for leveldb using c api

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cpy-leveldb's Introduction

cpy-leveldb

Python bindings for LevelDB using leveldb c api (http://code.google.com/p/leveldb/) author: Fu Haiping ([email protected])

1. Build Instructions

First of all, you need to build the included snappy and leveldb library.

1.1 Build Snappy

$ cd snappy
$ ./configure && make && make install

1.2 Build LevelDB

$ cd leveldb
$ make

1.3 Then, build the extension itself

$ python setup.py build

Example Usage

>>> import leveldb
>>> db = leveldb.LevelDB("/tmp/leveldb")
>>> db.Put("1", "111")
>>> db.Put("2", "222")
>>> db.Put("3", "333")
>>> db.Get("1")
'111'
>>> db.Get("3")
'333'
>>> db.Get("2")
'222'
>>> batch = leveldb.WriteBatch()
>>> for i in xrange(20):
... batch.Put(str(i), "hello world %i" % i)
... 
>>> db.Get("2")
'222'
>>> db.Get("5")
''
>>> db.Write(batch)
>>> db.Get("5")
'hello world 5'
>>> db.Get("2")
'hello world 2'
>>> iter = leveldb.Iterator(db)
Iterator_init executed.
>>> iter.First()
>>> iter.Key()
'0'
>>> iter.Value()
'hello world 0'
>>> iter.Last()
>>> iter.Key()
'9'
>>> iter.Value()
'hello world 9'
>>> iter.First()
>>> iter.Next()
>>> iter.Key()
'1'
>>> iter.Next()
>>> iter.Key()
'10'
>>> iter.Next()
>>> iter.Key()
'11'
>>> iter.Value()
'hello world 11'
>>> db.Put("1", "111")
>>> db.Put("2", "222")
>>> db.Put("3", "333")
>>> db.Get("1")
'111'
>>> snap = leveldb.Snapshot(db)
Snapshot_init executed.
>>> db.Delete("1")
>>> db.Get("1")
''
>>> snap.Set()
>>> db.Get("1")
'111'
>>> snap.Reset()
>>> db.Get("1")
''
>>> snap.Release()

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cpy-leveldb's Issues

some errors ...

i've just get the git clone of : git://github.com/forhappy/cpy-leveldb.git
i'm on ubuntu 11.10
here are my problem :

in /tmp/cpy-leveldb :
cd snappy
but no ./configure file need to ./autogen.sh first

after done everything in the README.TXT
all compile installation ok

But when try python and test leveldb i've got that :
the import of leveldb ok

Python 2.7.2+ (default, Oct 4 2011, 20:03:08)
[GCC 4.6.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
import leveldb
db = leveldb.LevelDB("/tmp/leveldb")
Traceback (most recent call last):
File "", line 1, in
AttributeError: 'module' object has no attribute 'LevelDB'

thks for help

invoke pure virtual function error

code:

!/usr/bin/env python

-- coding: utf-8 --

import datetime
import uuid
import leveldb

def main():
n=10000

print("%s: write %d items to db.."%(datetime.datetime.now(),n))

db = leveldb.LevelDB("./leveldb.db")
for i in range(n):
    db.Put(str(i), "this is item %d"%(i))

print("%s: lookup a item from map..."%(datetime.datetime.now()))
print(db.Get("43"))
print("%s: ok"%(datetime.datetime.now()))



return 0

if name == 'main':
main()

error when exit
#0 0x008aa410 in __kernel_vsyscall ()
#1 0x0099ddf0 in raise () from /lib/libc.so.6
#2 0x0099f701 in abort () from /lib/libc.so.6
#3 0x00275b10 in __gnu_cxx::__verbose_terminate_handler() () from /usr/lib/libstdc++.so.6
#4 0x00273515 in ?? () from /usr/lib/libstdc++.so.6
#5 0x00273552 in std::terminate() () from /usr/lib/libstdc++.so.6
#6 0x00273c75 in __cxa_pure_virtual () from /usr/lib/libstdc++.so.6
#7 0x0013c91f in leveldb::InternalKeyComparator::Compare(leveldb::Slice const&, leveldb::Slice const&) const ()

from /usr/local/lib/python2.7/site-packages/leveldb.so
#8 0x0014d779 in leveldb::(anonymous namespace)::MergingIterator::FindSmallest() () from /usr/local/lib/python2.7/site-packages/leveldb.so
#9 0x0014e05c in leveldb::(anonymous namespace)::MergingIterator::Next() () from /usr/local/lib/python2.7/site-packages/leveldb.so
#10 0x0013698e in leveldb::DBImpl::DoCompactionWork(leveldb::DBImpl::CompactionState*) () from /usr/local/lib/python2.7/site-packages/leveldb.so
#11 0x00137241 in leveldb::DBImpl::BackgroundCompaction() () from /usr/local/lib/python2.7/site-packages/leveldb.so
#12 0x001377e8 in leveldb::DBImpl::BackgroundCall() () from /usr/local/lib/python2.7/site-packages/leveldb.so
#13 0x00153f92 in leveldb::(anonymous namespace)::PosixEnv::BGThreadWrapper(void*) () from /usr/local/lib/python2.7/site-packages/leveldb.so
#14 0x00af1832 in start_thread () from /lib/libpthread.so.0
#15 0x00a46e0e in clone () from /lib/libc.so.6

when i get last version,when i maked, import leveldb,then raise a error

In [1]: import leveldb
ImportError Traceback (most recent call
last)

/home/xxxxx/ in ()

ImportError: libsnappy.so.1: cannot open shared object file: No such file or directory

ubuntu 11.04 python2.5 snappy r48

bloom filter require

I found that leveldb_options_set_filter_policy was not called in LevelDB_init . Does any reason to do so ?

/crtbeginT.o: could not read symbols: Bad value

Here's an error I get when I come to python setup.py build. Any ideas of how to resolve it? I use a Fedora system, leveldb and snappy compiled and installed fine.

gcc -pthread -shared build/temp.linux-x86_64-2.7/src/initmodule.o build/temp.linux-x86_64-2.7/src/leveldb.o build/temp.linux-x86_64-2.7/src/write_batch.o build/temp.linux-x86_64-2.7/src/iterator.o build/temp.linux-x86_64-2.7/src/snapshot.o build/temp.linux-x86_64-2.7/src/range_iterator.o -L/usr/lib64 -lpython2.7 -o build/lib.linux-x86_64-2.7/leveldb.so -L./leveldb -static -lleveldb -lsnappy -lpthread
/usr/bin/ld: /usr/lib/gcc/x86_64-redhat-linux/4.6.1/crtbeginT.o: relocation R_X86_64_32 against `DTOR_END' can not be used when making a shared object; recompile with -fPIC
/usr/lib/gcc/x86_64-redhat-linux/4.6.1/crtbeginT.o: could not read symbols: Bad value