C binding for leveldb, better readseq benchmark for SQLite.

- Added a C binding for LevelDB.
  May be useful as a stable ABI that can be used by 
  programs that keep leveldb in a shared library, 
  or for JNI API.

- Replaced SQLite's readseq benchmark to a more efficient version. 
  SQLite readseq speeds increased by about a factor of 2x 
  from the previous version. Also updated benchmark page to
  reflect readseq speed up.



git-svn-id: https://leveldb.googlecode.com/svn/trunk@46 62dab493-f737-651d-591e-8d6aee1b9529
This commit is contained in:
gabor@google.com
2011-08-05 20:40:49 +00:00
parent 1bfbe76b4e
commit 021ee9c32b
7 changed files with 1036 additions and 15 deletions

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db/c.cc Normal file
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "leveldb/c.h"
#include <stdlib.h>
#include <unistd.h>
#include "leveldb/cache.h"
#include "leveldb/comparator.h"
#include "leveldb/db.h"
#include "leveldb/env.h"
#include "leveldb/iterator.h"
#include "leveldb/options.h"
#include "leveldb/status.h"
#include "leveldb/write_batch.h"
namespace leveldb {
extern "C" {
struct leveldb_t { DB* rep; };
struct leveldb_iterator_t { Iterator* rep; };
struct leveldb_writebatch_t { WriteBatch rep; };
struct leveldb_snapshot_t { const Snapshot* rep; };
struct leveldb_readoptions_t { ReadOptions rep; };
struct leveldb_writeoptions_t { WriteOptions rep; };
struct leveldb_options_t { Options rep; };
struct leveldb_cache_t { Cache* rep; };
struct leveldb_seqfile_t { SequentialFile* rep; };
struct leveldb_randomfile_t { RandomAccessFile* rep; };
struct leveldb_writablefile_t { WritableFile* rep; };
struct leveldb_logger_t { Logger* rep; };
struct leveldb_filelock_t { FileLock* rep; };
struct leveldb_comparator_t : public Comparator {
void* state_;
void (*destructor_)(void*);
int (*compare_)(
void*,
const char* a, size_t alen,
const char* b, size_t blen);
const char* (*name_)(void*);
virtual ~leveldb_comparator_t() {
(*destructor_)(state_);
}
virtual int Compare(const Slice& a, const Slice& b) const {
return (*compare_)(state_, a.data(), a.size(), b.data(), b.size());
}
virtual const char* Name() const {
return (*name_)(state_);
}
// No-ops since the C binding does not support key shortening methods.
virtual void FindShortestSeparator(std::string*, const Slice&) const { }
virtual void FindShortSuccessor(std::string* key) const { }
};
struct leveldb_env_t {
Env* rep;
bool is_default;
};
static bool SaveError(char** errptr, const Status& s) {
assert(errptr != NULL);
if (s.ok()) {
return false;
} else if (*errptr == NULL) {
*errptr = strdup(s.ToString().c_str());
} else {
// TODO(sanjay): Merge with existing error?
free(*errptr);
*errptr = strdup(s.ToString().c_str());
}
return true;
}
static char* CopyString(const std::string& str) {
char* result = reinterpret_cast<char*>(malloc(sizeof(char) * str.size()));
memcpy(result, str.data(), sizeof(char) * str.size());
return result;
}
leveldb_t* leveldb_open(
const leveldb_options_t* options,
const char* name,
char** errptr) {
DB* db;
if (SaveError(errptr, DB::Open(options->rep, std::string(name), &db))) {
return NULL;
}
leveldb_t* result = new leveldb_t;
result->rep = db;
return result;
}
void leveldb_close(leveldb_t* db) {
delete db->rep;
delete db;
}
void leveldb_put(
leveldb_t* db,
const leveldb_writeoptions_t* options,
const char* key, size_t keylen,
const char* val, size_t vallen,
char** errptr) {
SaveError(errptr,
db->rep->Put(options->rep, Slice(key, keylen), Slice(val, vallen)));
}
void leveldb_delete(
leveldb_t* db,
const leveldb_writeoptions_t* options,
const char* key, size_t keylen,
char** errptr) {
SaveError(errptr, db->rep->Delete(options->rep, Slice(key, keylen)));
}
void leveldb_write(
leveldb_t* db,
const leveldb_writeoptions_t* options,
leveldb_writebatch_t* batch,
char** errptr) {
SaveError(errptr, db->rep->Write(options->rep, &batch->rep));
}
char* leveldb_get(
leveldb_t* db,
const leveldb_readoptions_t* options,
const char* key, size_t keylen,
size_t* vallen,
char** errptr) {
char* result = NULL;
std::string tmp;
Status s = db->rep->Get(options->rep, Slice(key, keylen), &tmp);
if (s.ok()) {
*vallen = tmp.size();
result = CopyString(tmp);
} else {
*vallen = 0;
if (!s.IsNotFound()) {
SaveError(errptr, s);
}
}
return result;
}
leveldb_iterator_t* leveldb_create_iterator(
leveldb_t* db,
const leveldb_readoptions_t* options) {
leveldb_iterator_t* result = new leveldb_iterator_t;
result->rep = db->rep->NewIterator(options->rep);
return result;
}
const leveldb_snapshot_t* leveldb_create_snapshot(
leveldb_t* db) {
leveldb_snapshot_t* result = new leveldb_snapshot_t;
result->rep = db->rep->GetSnapshot();
return result;
}
void leveldb_release_snapshot(
leveldb_t* db,
const leveldb_snapshot_t* snapshot) {
db->rep->ReleaseSnapshot(snapshot->rep);
delete snapshot;
}
const char* leveldb_property_value(
leveldb_t* db,
const char* propname) {
std::string tmp;
if (db->rep->GetProperty(Slice(propname), &tmp)) {
return CopyString(tmp);
} else {
return NULL;
}
}
void leveldb_approximate_sizes(
leveldb_t* db,
int num_ranges,
const char* const* range_start_key, const size_t* range_start_key_len,
const char* const* range_limit_key, const size_t* range_limit_key_len,
uint64_t* sizes) {
Range* ranges = new Range[num_ranges];
for (int i = 0; i < num_ranges; i++) {
ranges[i].start = Slice(range_start_key[i], range_start_key_len[i]);
ranges[i].limit = Slice(range_limit_key[i], range_limit_key_len[i]);
}
db->rep->GetApproximateSizes(ranges, num_ranges, sizes);
delete[] ranges;
}
void leveldb_destroy_db(
const leveldb_options_t* options,
const char* name,
char** errptr) {
SaveError(errptr, DestroyDB(name, options->rep));
}
void leveldb_repair_db(
const leveldb_options_t* options,
const char* name,
char** errptr) {
SaveError(errptr, RepairDB(name, options->rep));
}
void leveldb_iter_destroy(leveldb_iterator_t* iter) {
delete iter->rep;
delete iter;
}
unsigned char leveldb_iter_valid(const leveldb_iterator_t* iter) {
return iter->rep->Valid();
}
void leveldb_iter_seek_to_first(leveldb_iterator_t* iter) {
iter->rep->SeekToFirst();
}
void leveldb_iter_seek_to_last(leveldb_iterator_t* iter) {
iter->rep->SeekToLast();
}
void leveldb_iter_seek(leveldb_iterator_t* iter, const char* k, size_t klen) {
iter->rep->Seek(Slice(k, klen));
}
void leveldb_iter_next(leveldb_iterator_t* iter) {
iter->rep->Next();
}
void leveldb_iter_prev(leveldb_iterator_t* iter) {
iter->rep->Prev();
}
const char* leveldb_iter_key(const leveldb_iterator_t* iter, size_t* klen) {
Slice s = iter->rep->key();
*klen = s.size();
return s.data();
}
const char* leveldb_iter_value(const leveldb_iterator_t* iter, size_t* vlen) {
Slice s = iter->rep->value();
*vlen = s.size();
return s.data();
}
void leveldb_iter_get_error(const leveldb_iterator_t* iter, char** errptr) {
SaveError(errptr, iter->rep->status());
}
leveldb_writebatch_t* leveldb_writebatch_create() {
return new leveldb_writebatch_t;
}
void leveldb_writebatch_destroy(leveldb_writebatch_t* b) {
delete b;
}
void leveldb_writebatch_clear(leveldb_writebatch_t* b) {
b->rep.Clear();
}
void leveldb_writebatch_put(
leveldb_writebatch_t* b,
const char* key, size_t klen,
const char* val, size_t vlen) {
b->rep.Put(Slice(key, klen), Slice(val, vlen));
}
void leveldb_writebatch_delete(
leveldb_writebatch_t* b,
const char* key, size_t klen) {
b->rep.Delete(Slice(key, klen));
}
void leveldb_writebatch_iterate(
leveldb_writebatch_t* b,
void* state,
void (*put)(void*, const char* k, size_t klen, const char* v, size_t vlen),
void (*deleted)(void*, const char* k, size_t klen)) {
class H : public WriteBatch::Handler {
public:
void* state_;
void (*put_)(void*, const char* k, size_t klen, const char* v, size_t vlen);
void (*deleted_)(void*, const char* k, size_t klen);
virtual void Put(const Slice& key, const Slice& value) {
(*put_)(state_, key.data(), key.size(), value.data(), value.size());
}
virtual void Delete(const Slice& key) {
(*deleted_)(state_, key.data(), key.size());
}
};
H handler;
handler.state_ = state;
handler.put_ = put;
handler.deleted_ = deleted;
b->rep.Iterate(&handler);
}
leveldb_options_t* leveldb_options_create() {
return new leveldb_options_t;
}
void leveldb_options_destroy(leveldb_options_t* options) {
delete options;
}
void leveldb_options_set_comparator(
leveldb_options_t* opt,
leveldb_comparator_t* cmp) {
opt->rep.comparator = cmp;
}
void leveldb_options_set_create_if_missing(
leveldb_options_t* opt, unsigned char v) {
opt->rep.create_if_missing = v;
}
void leveldb_options_set_error_if_exists(
leveldb_options_t* opt, unsigned char v) {
opt->rep.error_if_exists = v;
}
void leveldb_options_set_paranoid_checks(
leveldb_options_t* opt, unsigned char v) {
opt->rep.paranoid_checks = v;
}
void leveldb_options_set_env(leveldb_options_t* opt, leveldb_env_t* env) {
opt->rep.env = (env ? env->rep : NULL);
}
void leveldb_options_set_info_log(leveldb_options_t* opt, leveldb_logger_t* l) {
opt->rep.info_log = (l ? l->rep : NULL);
}
void leveldb_options_set_write_buffer_size(leveldb_options_t* opt, size_t s) {
opt->rep.write_buffer_size = s;
}
void leveldb_options_set_max_open_files(leveldb_options_t* opt, int n) {
opt->rep.max_open_files = n;
}
void leveldb_options_set_cache(leveldb_options_t* opt, leveldb_cache_t* c) {
opt->rep.block_cache = c->rep;
}
void leveldb_options_set_block_size(leveldb_options_t* opt, size_t s) {
opt->rep.block_size = s;
}
void leveldb_options_set_block_restart_interval(leveldb_options_t* opt, int n) {
opt->rep.block_restart_interval = n;
}
void leveldb_options_set_compression(leveldb_options_t* opt, int t) {
opt->rep.compression = static_cast<CompressionType>(t);
}
leveldb_comparator_t* leveldb_comparator_create(
void* state,
void (*destructor)(void*),
int (*compare)(
void*,
const char* a, size_t alen,
const char* b, size_t blen),
const char* (*name)(void*)) {
leveldb_comparator_t* result = new leveldb_comparator_t;
result->state_ = state;
result->destructor_ = destructor;
result->compare_ = compare;
result->name_ = name;
return result;
}
void leveldb_comparator_destroy(leveldb_comparator_t* cmp) {
delete cmp;
}
leveldb_readoptions_t* leveldb_readoptions_create() {
return new leveldb_readoptions_t;
}
void leveldb_readoptions_destroy(leveldb_readoptions_t* opt) {
delete opt;
}
void leveldb_readoptions_set_verify_checksums(
leveldb_readoptions_t* opt,
unsigned char v) {
opt->rep.verify_checksums = v;
}
void leveldb_readoptions_set_fill_cache(
leveldb_readoptions_t* opt, unsigned char v) {
opt->rep.fill_cache = v;
}
void leveldb_readoptions_set_snapshot(
leveldb_readoptions_t* opt,
const leveldb_snapshot_t* snap) {
opt->rep.snapshot = (snap ? snap->rep : NULL);
}
leveldb_writeoptions_t* leveldb_writeoptions_create() {
return new leveldb_writeoptions_t;
}
void leveldb_writeoptions_destroy(leveldb_writeoptions_t* opt) {
delete opt;
}
void leveldb_writeoptions_set_sync(
leveldb_writeoptions_t* opt, unsigned char v) {
opt->rep.sync = v;
}
leveldb_cache_t* leveldb_cache_create_lru(size_t capacity) {
leveldb_cache_t* c = new leveldb_cache_t;
c->rep = NewLRUCache(capacity);
return c;
}
void leveldb_cache_destroy(leveldb_cache_t* cache) {
delete cache->rep;
delete cache;
}
leveldb_env_t* leveldb_create_default_env() {
leveldb_env_t* result = new leveldb_env_t;
result->rep = Env::Default();
result->is_default = true;
return result;
}
void leveldb_env_destroy(leveldb_env_t* env) {
if (!env->is_default) delete env->rep;
delete env;
}
} // end extern "C"
}

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/* Copyright (c) 2011 The LevelDB Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file. See the AUTHORS file for names of contributors. */
#include "leveldb/c.h"
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
const char* phase = "";
static char dbname[200];
static void StartPhase(const char* name) {
fprintf(stderr, "=== Test %s\n", name);
phase = name;
}
#define CheckNoError(err) \
if ((err) != NULL) { \
fprintf(stderr, "%s:%d: %s: %s\n", __FILE__, __LINE__, phase, (err)); \
abort(); \
}
#define CheckCondition(cond) \
if (!(cond)) { \
fprintf(stderr, "%s:%d: %s: %s\n", __FILE__, __LINE__, phase, #cond); \
abort(); \
}
static void CheckEqual(const char* expected, const char* v, size_t n) {
if (expected == NULL && v == NULL) {
// ok
} else if (expected != NULL && v != NULL && n == strlen(expected) &&
memcmp(expected, v, n) == 0) {
// ok
return;
} else {
fprintf(stderr, "%s: expected '%s', got '%s'\n",
phase,
(expected ? expected : "(null)"),
(v ? v : "(null"));
abort();
}
}
static void Free(char** ptr) {
if (*ptr) {
free(*ptr);
*ptr = NULL;
}
}
static void CheckGet(
leveldb_t* db,
const leveldb_readoptions_t* options,
const char* key,
const char* expected) {
char* err = NULL;
size_t val_len;
char* val;
val = leveldb_get(db, options, key, strlen(key), &val_len, &err);
CheckNoError(err);
CheckEqual(expected, val, val_len);
Free(&val);
}
static void CheckIter(leveldb_iterator_t* iter,
const char* key, const char* val) {
size_t len;
const char* str;
str = leveldb_iter_key(iter, &len);
CheckEqual(key, str, len);
str = leveldb_iter_value(iter, &len);
CheckEqual(val, str, len);
}
// Callback from leveldb_writebatch_iterate()
static void CheckPut(void* ptr,
const char* k, size_t klen,
const char* v, size_t vlen) {
int* state = (int*) ptr;
CheckCondition(*state < 2);
switch (*state) {
case 0:
CheckEqual("bar", k, klen);
CheckEqual("b", v, vlen);
break;
case 1:
CheckEqual("box", k, klen);
CheckEqual("c", v, vlen);
break;
}
(*state)++;
}
// Callback from leveldb_writebatch_iterate()
static void CheckDel(void* ptr, const char* k, size_t klen) {
int* state = (int*) ptr;
CheckCondition(*state == 2);
CheckEqual("bar", k, klen);
(*state)++;
}
static void CmpDestroy(void* arg) { }
static int CmpCompare(void* arg, const char* a, size_t alen,
const char* b, size_t blen) {
int n = (alen < blen) ? alen : blen;
int r = memcmp(a, b, n);
if (r == 0) {
if (alen < blen) r = -1;
else if (alen > blen) r = +1;
}
return r;
}
static const char* CmpName(void* arg) {
return "foo";
}
int main(int argc, char** argv) {
leveldb_t* db;
leveldb_comparator_t* cmp;
leveldb_cache_t* cache;
leveldb_env_t* env;
leveldb_options_t* options;
leveldb_readoptions_t* roptions;
leveldb_writeoptions_t* woptions;
char* err = NULL;
snprintf(dbname, sizeof(dbname), "/tmp/leveldb_c_test-%d",
((int) geteuid()));
StartPhase("create_objects");
cmp = leveldb_comparator_create(NULL, CmpDestroy, CmpCompare, CmpName);
env = leveldb_create_default_env();
cache = leveldb_cache_create_lru(100000);
options = leveldb_options_create();
leveldb_options_set_comparator(options, cmp);
leveldb_options_set_error_if_exists(options, 1);
leveldb_options_set_cache(options, cache);
leveldb_options_set_env(options, env);
leveldb_options_set_info_log(options, NULL);
leveldb_options_set_write_buffer_size(options, 100000);
leveldb_options_set_paranoid_checks(options, 1);
leveldb_options_set_max_open_files(options, 10);
leveldb_options_set_block_size(options, 1024);
leveldb_options_set_block_restart_interval(options, 8);
leveldb_options_set_compression(options, leveldb_no_compression);
roptions = leveldb_readoptions_create();
leveldb_readoptions_set_verify_checksums(roptions, 1);
leveldb_readoptions_set_fill_cache(roptions, 0);
woptions = leveldb_writeoptions_create();
leveldb_writeoptions_set_sync(woptions, 1);
StartPhase("destroy");
leveldb_destroy_db(options, dbname, &err);
Free(&err);
StartPhase("open_error");
db = leveldb_open(options, dbname, &err);
CheckCondition(err != NULL);
Free(&err);
StartPhase("open");
leveldb_options_set_create_if_missing(options, 1);
db = leveldb_open(options, dbname, &err);
CheckNoError(err);
CheckGet(db, roptions, "foo", NULL);
StartPhase("put");
leveldb_put(db, woptions, "foo", 3, "hello", 5, &err);
CheckNoError(err);
CheckGet(db, roptions, "foo", "hello");
StartPhase("writebatch");
{
leveldb_writebatch_t* wb = leveldb_writebatch_create();
leveldb_writebatch_put(wb, "foo", 3, "a", 1);
leveldb_writebatch_clear(wb);
leveldb_writebatch_put(wb, "bar", 3, "b", 1);
leveldb_writebatch_put(wb, "box", 3, "c", 1);
leveldb_writebatch_delete(wb, "bar", 3);
leveldb_write(db, woptions, wb, &err);
CheckNoError(err);
CheckGet(db, roptions, "foo", "hello");
CheckGet(db, roptions, "bar", NULL);
CheckGet(db, roptions, "box", "c");
int pos = 0;
leveldb_writebatch_iterate(wb, &pos, CheckPut, CheckDel);
CheckCondition(pos == 3);
leveldb_writebatch_destroy(wb);
}
StartPhase("iter");
{
leveldb_iterator_t* iter = leveldb_create_iterator(db, roptions);
CheckCondition(!leveldb_iter_valid(iter));
leveldb_iter_seek_to_first(iter);
CheckCondition(leveldb_iter_valid(iter));
CheckIter(iter, "box", "c");
leveldb_iter_next(iter);
CheckIter(iter, "foo", "hello");
leveldb_iter_prev(iter);
CheckIter(iter, "box", "c");
leveldb_iter_prev(iter);
CheckCondition(!leveldb_iter_valid(iter));
leveldb_iter_seek_to_last(iter);
CheckIter(iter, "foo", "hello");
leveldb_iter_seek(iter, "b", 1);
CheckIter(iter, "box", "c");
leveldb_iter_get_error(iter, &err);
CheckNoError(err);
leveldb_iter_destroy(iter);
}
StartPhase("approximate_sizes");
{
int i;
int n = 20000;
char keybuf[100];
char valbuf[100];
uint64_t sizes[2];
const char* start[2] = { "a", "k00000000000000010000" };
size_t start_len[2] = { 1, 21 };
const char* limit[2] = { "k00000000000000010000", "z" };
size_t limit_len[2] = { 21, 1 };
leveldb_writeoptions_set_sync(woptions, 0);
for (i = 0; i < n; i++) {
snprintf(keybuf, sizeof(keybuf), "k%020d", i);
snprintf(valbuf, sizeof(valbuf), "v%020d", i);
leveldb_put(db, woptions, keybuf, strlen(keybuf), valbuf, strlen(valbuf),
&err);
CheckNoError(err);
}
leveldb_approximate_sizes(db, 2, start, start_len, limit, limit_len, sizes);
CheckCondition(sizes[0] > 0);
CheckCondition(sizes[1] > 0);
}
StartPhase("property");
{
char* prop = leveldb_property_value(db, "nosuchprop");
CheckCondition(prop == NULL);
prop = leveldb_property_value(db, "leveldb.stats");
CheckCondition(prop != NULL);
Free(&prop);
}
StartPhase("snapshot");
{
const leveldb_snapshot_t* snap;
snap = leveldb_create_snapshot(db);
leveldb_delete(db, woptions, "foo", 3, &err);
CheckNoError(err);
leveldb_readoptions_set_snapshot(roptions, snap);
CheckGet(db, roptions, "foo", "hello");
leveldb_readoptions_set_snapshot(roptions, NULL);
CheckGet(db, roptions, "foo", NULL);
leveldb_release_snapshot(db, snap);
}
StartPhase("repair");
{
leveldb_close(db);
leveldb_options_set_create_if_missing(options, 0);
leveldb_options_set_error_if_exists(options, 0);
leveldb_repair_db(options, dbname, &err);
CheckNoError(err);
db = leveldb_open(options, dbname, &err);
CheckNoError(err);
CheckGet(db, roptions, "foo", NULL);
CheckGet(db, roptions, "bar", NULL);
CheckGet(db, roptions, "box", "c");
}
StartPhase("cleanup");
leveldb_close(db);
leveldb_options_destroy(options);
leveldb_readoptions_destroy(roptions);
leveldb_writeoptions_destroy(woptions);
leveldb_cache_destroy(cache);
leveldb_comparator_destroy(cmp);
leveldb_env_destroy(env);
fprintf(stderr, "PASS\n");
return 0;
}