- 下载代码
- 解压
make && sudo make install
注意需要的是lmdb.h还是lmdb++.h。
- 配置
检查.bashrc的，如果没有/usr/local/lib，要加上。
- 简单测试
先在当前目录先：
mkdir testdb
再执行：
./mtest
- 代码如下
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <pthread.h> #include <unistd.h> #include <fcntl.h> #include <math.h> #include <time.h> #include <sys/time.h> #include <sys/stat.h> #include "lmdb.h" #define E(expr) CHECK((rc = (expr)) == MDB_SUCCESS, #expr) #define RES(err, expr) ((rc = expr) == (err) || (CHECK(!rc, #expr), 0)) #define CHECK(test, msg) ((test) ? (void)0 : ((void)fprintf(stderr, \ "%s:%d: %s: %s\n", __FILE__, __LINE__, msg, mdb_strerror(rc)), abort())) #define TEST_DB_DIR "./testdb" int main(int argc,char * argv[]) { int i = 0, j = 0, rc; MDB_env *env; MDB_dbi dbi; MDB_val key, data; MDB_txn *txn; MDB_stat mst; MDB_cursor *cursor, *cur2; MDB_cursor_op op; int count; int *values; char sval[32] = ""; mkdir(TEST_DB_DIR, S_IRWXU | S_IRWXG | S_IRWXO); srand(time(NULL)); count = (rand()%384) + 64; values = (int *)malloc(count*sizeof(int)); for(i = 0;i<count;i++) { values[i] = rand()%1024; } E(mdb_env_create(&env)); E(mdb_env_set_maxreaders(env, 1)); E(mdb_env_set_mapsize(env, 10485760)); E(mdb_env_open(env, TEST_DB_DIR, MDB_FIXEDMAP /*|MDB_NOSYNC*/, 0664)); E(mdb_txn_begin(env, NULL, 0, &txn)); E(mdb_dbi_open(txn, NULL, 0, &dbi)); key.mv_size = sizeof(int); key.mv_data = sval; printf("Adding %d values\n", count); for (i=0;i<count;i++) { sprintf(sval, "%03x %d foo bar", values[i], values[i]); /* Set <data> in each iteration, since MDB_NOOVERWRITE may modify it */ data.mv_size = sizeof(sval); data.mv_data = sval; if (RES(MDB_KEYEXIST, mdb_put(txn, dbi, &key, &data, MDB_NOOVERWRITE))) { j++; data.mv_size = sizeof(sval); data.mv_data = sval; } } if (j) printf("%d duplicates skipped\n", j); E(mdb_txn_commit(txn)); E(mdb_env_stat(env, &mst)); E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn)); E(mdb_cursor_open(txn, dbi, &cursor)); while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) { printf("key: %p %.*s, data: %p %.*s\n", key.mv_data, (int) key.mv_size, (char *) key.mv_data, data.mv_data, (int) data.mv_size, (char *) data.mv_data); } CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get"); mdb_cursor_close(cursor); mdb_txn_abort(txn); j=0; key.mv_data = sval; for (i= count - 1; i > -1; i-= (rand()%5)) { j++; txn=NULL; E(mdb_txn_begin(env, NULL, 0, &txn)); sprintf(sval, "%03x ", values[i]); if (RES(MDB_NOTFOUND, mdb_del(txn, dbi, &key, NULL))) { j--; mdb_txn_abort(txn); } else { E(mdb_txn_commit(txn)); } } free(values); printf("Deleted %d values\n", j); E(mdb_env_stat(env, &mst)); E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn)); E(mdb_cursor_open(txn, dbi, &cursor)); printf("Cursor next\n"); while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) { printf("key: %.*s, data: %.*s\n", (int) key.mv_size, (char *) key.mv_data, (int) data.mv_size, (char *) data.mv_data); } CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get"); printf("Cursor last\n"); E(mdb_cursor_get(cursor, &key, &data, MDB_LAST)); printf("key: %.*s, data: %.*s\n", (int) key.mv_size, (char *) key.mv_data, (int) data.mv_size, (char *) data.mv_data); printf("Cursor prev\n"); while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_PREV)) == 0) { printf("key: %.*s, data: %.*s\n", (int) key.mv_size, (char *) key.mv_data, (int) data.mv_size, (char *) data.mv_data); } CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get"); printf("Cursor last/prev\n"); E(mdb_cursor_get(cursor, &key, &data, MDB_LAST)); printf("key: %.*s, data: %.*s\n", (int) key.mv_size, (char *) key.mv_data, (int) data.mv_size, (char *) data.mv_data); E(mdb_cursor_get(cursor, &key, &data, MDB_PREV)); printf("key: %.*s, data: %.*s\n", (int) key.mv_size, (char *) key.mv_data, (int) data.mv_size, (char *) data.mv_data); mdb_cursor_close(cursor); mdb_txn_abort(txn); printf("Deleting with cursor\n"); E(mdb_txn_begin(env, NULL, 0, &txn)); E(mdb_cursor_open(txn, dbi, &cur2)); for (i=0; i<50; i++) { if (RES(MDB_NOTFOUND, mdb_cursor_get(cur2, &key, &data, MDB_NEXT))) break; printf("key: %p %.*s, data: %p %.*s\n", key.mv_data, (int) key.mv_size, (char *) key.mv_data, data.mv_data, (int) data.mv_size, (char *) data.mv_data); E(mdb_del(txn, dbi, &key, NULL)); } printf("Restarting cursor in txn\n"); for (op=MDB_FIRST, i=0; i<=32; op=MDB_NEXT, i++) { if (RES(MDB_NOTFOUND, mdb_cursor_get(cur2, &key, &data, op))) break; printf("key: %p %.*s, data: %p %.*s\n", key.mv_data, (int) key.mv_size, (char *) key.mv_data, data.mv_data, (int) data.mv_size, (char *) data.mv_data); } mdb_cursor_close(cur2); E(mdb_txn_commit(txn)); printf("Restarting cursor outside txn\n"); E(mdb_txn_begin(env, NULL, 0, &txn)); E(mdb_cursor_open(txn, dbi, &cursor)); for (op=MDB_FIRST, i=0; i<=32; op=MDB_NEXT, i++) { if (RES(MDB_NOTFOUND, mdb_cursor_get(cursor, &key, &data, op))) break; printf("key: %p %.*s, data: %p %.*s\n", key.mv_data, (int) key.mv_size, (char *) key.mv_data, data.mv_data, (int) data.mv_size, (char *) data.mv_data); } mdb_cursor_close(cursor); mdb_txn_abort(txn); mdb_dbi_close(env, dbi); mdb_env_close(env); return 0; }
