mtest.c

/* mtest8.c - memory-mapped database tester/toy */
/*
 * Copyright 2013 Dimitrij Denissenko, Black Square Media
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted only as authorized by the OpenLDAP
 * Public License.
 *
 * A copy of this license is available in the file LICENSE in the
 * top-level directory of the distribution or, alternatively, at
 * <http://www.OpenLDAP.org/license.html>.
 */

/* Tests for multi-process access */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include "lmdb.h"

int createEnv(MDB_env **env, MDB_dbi *dbi) {
	int rc;
	MDB_txn *txn;

	if ((rc = mdb_env_create(env))) return rc;
	if ((rc = mdb_env_set_mapsize(*env, 2048LL*1024*1024))) return rc;
	if ((rc = mdb_env_set_maxdbs(*env, 4))) return rc;
	if ((rc = mdb_env_open(*env, "./testdb", MDB_FIXEDMAP|MDB_NOSYNC, 0664))) return rc;
	if ((rc = mdb_txn_begin(*env, NULL, 0, &txn))) return rc;
	if ((rc = mdb_open(txn, NULL, MDB_CREATE, dbi))) return rc;
	if ((rc = mdb_txn_commit(txn))) return rc;
	return rc;
}

int bulkWrite(int mode) {
	char skey[32];
	char sval[64];
	MDB_env *env = NULL;
	MDB_dbi dbi;
	MDB_txn *txn;
	MDB_val key, data;
	pid_t childpid = 0;
	int rc = MDB_SUCCESS;
	int keys = 10000;

	if ((rc = createEnv(&env, &dbi))) goto cleanup;

	while (keys--) {
		sprintf(skey, "%08x", keys);
		key.mv_size = 8;
		key.mv_data = skey;
		data.mv_size = sizeof(sval);
		data.mv_data = sval;

		if ((rc = mdb_txn_begin(env, NULL, 0, &txn))) goto cleanup;
		if ((rc = mdb_put(txn,dbi,&key,&data,0))) goto cleanup;
		if ((rc = mdb_txn_commit(txn))) goto cleanup;

		if ((keys % 1000) == 0) {
			mdb_env_close(env);
			env = NULL;

			/* Wait for previous children */
			if (childpid) {
				int status;
				waitpid(childpid, &status, 0);
				childpid = 0;
			}

			/* Child */
			if (mode && (childpid = fork()) == 0) {
				char *tmpfile = "./testdb/backup.mdb";
				unlink(tmpfile);

				int fd = open(tmpfile,O_CREAT|O_WRONLY|O_EXCL,0644);
				if (fd == -1) {
					printf("Error in child: %s\n",strerror(errno));
					exit(1);
				}
				rc = createEnv(&env, &dbi);
				if (mode == 2 && !rc) rc = mdb_env_copyfd(env, fd);
				close(fd);
				if (rc) printf("Error in child: %s\n", mdb_strerror(rc));

				if (env) mdb_env_close(env);
				exit(0);
			} else {
				if ((rc = createEnv(&env, &dbi))) goto cleanup;
			}
		}
	}

cleanup:
	if (env) mdb_env_close(env);
	return rc;
}

int main(int argc,char * argv[]) {
	int rc;
	struct stat sb;

	unlink("./testdb/data.mdb");
	if ((rc = bulkWrite(0))) {
		printf("Error: %s\n", mdb_strerror(rc));
		return 1;
	}
	if (stat("./testdb/data.mdb", &sb) == -1) {
		printf("Error: %s\n", strerror(errno));
		return 1;
	}
	printf("NO FORK     : %zu\n", sb.st_size);

	unlink("./testdb/data.mdb");
	if ((rc = bulkWrite(1))) {
		printf("Error: %s\n", mdb_strerror(rc));
		return 1;
	}
	if (stat("./testdb/data.mdb", &sb) == -1) {
		printf("Error: %s\n", strerror(errno));
		return 1;
	}
	printf("FORK & OPEN : %zu\n", sb.st_size);

	unlink("./testdb/data.mdb");
	if ((rc = bulkWrite(2))) {
		printf("Error: %s\n", mdb_strerror(rc));
		return 1;
	}
	if (stat("./testdb/data.mdb", &sb) == -1) {
		printf("Error: %s\n", strerror(errno));
		return 1;
	}
	printf("FORK & COPY : %zu\n", sb.st_size);

	return 0;
}