IOWOW - The C11 persistent key/value database engine based on skip list
Website http://iowow.io
- iwkv.h Persistent key/value database engine
- iwfsmfile.h File blocks allocation manager like
malloc()on files
- Support of multiple key-value databases within a single file
- Online database backups
- Native support of integer keys
- Write Ahead Logging (WAL) support
- Ultra-fast traversal of database records
- Compound keys support
- Good performance comparing its main competitors:
lmdb,leveldb,kyoto cabinet - Tiny C11 library (200Kb) can be easily embedded into any software
- EJDB - Embeddable JSON database engine. http://ejdb.org
- Maximum iwkv storage file size:
512 GB (0x7fffffff80) - Total size of a single key+value record must be not greater than
255Mb (0xfffffff) - In-memory cache for every opened database takes
~130Kb, cache can be disposed byiwkv_db_cache_release()
sudo add-apt-repository ppa:adamansky/iwowow
sudo apt-get update
sudo apt-get install iowowmkdir build && cd build
cmake .. -DCMAKE_BUILD_TYPE=Release -DPACKAGE_DEB=ON
make packagemkdir build && cd build
cmake .. -DCMAKE_BUILD_TYPE=Release -DPACKAGE_RPM=ON
make packageSuccessfully tested on FreeBSD 10/11
Successfully tested on OSX 10.12/10.13
Successfully tested on Debian 9.4, MIPS 32, gcc 6.x compiler.
#include <iowow/iwkv.h>
#include <string.h>
#include <stdlib.h>
int main() {
IWKV_OPTS opts = {
.path = "example1.db",
.oflags = IWKV_TRUNC // Cleanup database before open
};
IWKV iwkv;
IWDB mydb;
iwrc rc = iwkv_open(&opts, &iwkv);
if (rc) {
iwlog_ecode_error3(rc);
return 1;
}
// Now open mydb
// - Database id: 1
rc = iwkv_db(iwkv, 1, 0, &mydb);
if (rc) {
iwlog_ecode_error2(rc, "Failed to open mydb");
return 1;
}
// Work with db: put/get value
IWKV_val key, val;
key.data = "foo";
key.size = strlen(key.data);
val.data = "bar";
val.size = strlen(val.data);
fprintf(stdout, "put: %.*s => %.*s\n",
(int) key.size, (char *) key.data,
(int) val.size, (char *) val.data);
rc = iwkv_put(mydb, &key, &val, 0);
if (rc) {
iwlog_ecode_error3(rc);
return rc;
}
// Retrieve value associated with `foo` key
val.data = 0;
val.size = 0;
rc = iwkv_get(mydb, &key, &val);
if (rc) {
iwlog_ecode_error3(rc);
return rc;
}
fprintf(stdout, "get: %.*s => %.*s\n",
(int) key.size, (char *) key.data,
(int) val.size, (char *) val.data);
iwkv_val_dispose(&val);
iwkv_close(&iwkv);
return 0;
}Compile and run:
gcc -std=gnu11 -Wall -pedantic -c -o example1.o example1.c
gcc -o example1 example1.o -liowow
./example1
put: foo => bar
get: foo => bar///
/// Fills database with a set of football table records
/// then traverse records according to club name in ascending and descending orders.
///
#include "iwkv.h"
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
static struct data_s {
const char *club;
uint8_t points;
} _points[] = {
{ "Aston Villa", 25 },
{ "Manchester City", 57 },
{ "Arsenal", 40 },
{ "Everton", 37 },
{ "West Ham United", 27 },
{ "Tottenham Hotspur", 41 },
{ "Wolverhampton Wanderers", 43 },
{ "Norwich City", 21 },
{ "Leicester City", 53 },
{ "Manchester United", 45 },
{ "Newcastle United", 35 },
{ "Brighton & Hove Albion", 29 },
{ "AFC Bournemouth", 27 },
{ "Crystal Palace", 39 },
{ "Sheffield United", 43 },
{ "Burnley", 39 },
{ "Southampton", 34 },
{ "Watford", 27 },
{ "Chelsea", 48 },
{ "Liverpool", 82 },
};
static iwrc run(void) {
IWKV_OPTS opts = {
.path = "cursor1.db",
.oflags = IWKV_TRUNC // Cleanup database before open
};
IWKV iwkv;
IWDB db;
IWKV_cursor cur = 0;
iwrc rc = iwkv_open(&opts, &iwkv);
RCRET(rc);
rc = iwkv_db(iwkv, 1, 0, &db);
RCGO(rc, finish);
for (int i = 0; i < sizeof(_points) / sizeof(_points[0]); ++i) {
struct data_s *n = &_points[i];
IWKV_val key = { .data = (void *) n->club, .size = strlen(n->club) };
IWKV_val val = { .data = &n->points, .size = sizeof(n->points) };
RCHECK(rc, finish, iwkv_put(db, &key, &val, 0));
}
// Interate clubs in descending order
RCHECK(rc, finish, iwkv_cursor_open(db, &cur, IWKV_CURSOR_BEFORE_FIRST, 0));
while ((rc = iwkv_cursor_to(cur, IWKV_CURSOR_NEXT)) != IWKV_ERROR_NOTFOUND) {
IWKV_val key, val;
RCHECK(rc, finish, iwkv_cursor_get(cur, &key, &val));
fprintf(stdout, "%.*s: %u\n",
(int) key.size, (char *) key.data,
*(uint8_t *) val.data);
iwkv_kv_dispose(&key, &val);
}
rc = 0;
iwkv_cursor_close(&cur);
fprintf(stdout, "\n\n");
RCHECK(rc, finish, iwkv_cursor_open(db, &cur, IWKV_CURSOR_AFTER_LAST, 0));
while ((rc = iwkv_cursor_to(cur, IWKV_CURSOR_PREV)) != IWKV_ERROR_NOTFOUND) {
IWKV_val key, val;
RCHECK(rc, finish, iwkv_cursor_get(cur, &key, &val));
fprintf(stdout, "%.*s: %u\n",
(int) key.size, (char *) key.data,
*(uint8_t *) val.data);
iwkv_kv_dispose(&key, &val);
}
rc = 0;
finish:
if (cur) {
iwkv_cursor_close(&cur);
}
iwkv_close(&iwkv);
return rc;
}
int main() {
iwrc rc = run();
RCGO(rc, finish);
finish:
if (rc) {
iwlog_ecode_error3(rc);
}
return 0;
}