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fdatasync()????????????????
???????????????????????????????????????????????????????db4o???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
?????????????????????????????????????????????????????????????????
POSIX???OS???fsync()??????fdatasync()???????????????????????????????????????????????????????????????????????fsync()???????????fdatasync()??????????10-20%??????????????
????????db4o?????????db4o?IoAdapter?????????I/O??????????????????JNI?POSIX?fdatasync()????????????
?????????????IoAdapter??????????????????????
Code:
#include <jni.h> | |
#include "LinuxIoAdapter.h" | |
#include <stdio.h> | |
#include <sys/types.h> | |
#include <sys/stat.h> | |
#include <fcntl.h> | |
| |
/* | |
* Class: LinuxIoAdapter | |
* Method: openFile | |
* Signature: (Ljava/lang/String;ZJ)J | |
*/ | |
JNIEXPORT jint JNICALL Java_LinuxIoAdapter_openFile | |
(JNIEnv *env, jclass jc, jstring path, jboolean lockfile, jlong initiallength) | |
{ | |
printf("openFile\n"); | |
const jbyte *filename = (*env)->GetStringUTFChars(env, path, NULL); | |
| |
if(filename == NULL){ | |
return 0; // OutOfMemoryError or NULL value | |
} | |
| |
int fd = open(filename, O_RDWR|O_CREAT, 0644); | |
| |
if(fd < 0){ | |
printf("open failed\n"); | |
} | |
| |
(*env)->ReleaseStringChars(env, path, NULL); | |
| |
return fd; | |
| |
} | |
| |
/* | |
* Class: LinuxIoAdapter | |
* Method: closeFile | |
* Signature: (J)V | |
*/ | |
JNIEXPORT void JNICALL Java_LinuxIoAdapter_closeFile | |
(JNIEnv * env, jclass jc, jint handle) | |
{ | |
printf("closeFile\n"); | |
if(close(handle) < 0){ | |
printf("close failed\n"); | |
} | |
| |
} | |
| |
/* | |
* Class: LinuxIoAdapter | |
* Method: getLength | |
* Signature: (J)J | |
*/ | |
JNIEXPORT jlong JNICALL Java_LinuxIoAdapter_getLength | |
(JNIEnv *env, jclass jc, jint handle) | |
{ | |
struct stat st; | |
fstat(handle, &st); | |
return st.st_size; | |
} | |
| |
/* | |
* Class: LinuxIoAdapter | |
* Method: read | |
* Signature: (J[BI)I | |
*/ | |
JNIEXPORT jint JNICALL Java_LinuxIoAdapter_read | |
(JNIEnv *env, jclass jc, jint handle, jbyteArray bytes, jint length) | |
{ | |
| |
jbyte buf[length]; | |
| |
ssize_t n = read(handle, &buf, length); | |
| |
if(n != length) | |
printf("read failed: %i->%i", length, n); | |
| |
(*env)->SetByteArrayRegion(env, bytes, 0, length, buf); | |
| |
return n; | |
} | |
| |
/* | |
* Class: LinuxIoAdapter | |
* Method: seek | |
* Signature: (JJ)V | |
*/ | |
JNIEXPORT void JNICALL Java_LinuxIoAdapter_seek | |
(JNIEnv *env, jclass jc, jint handle, jlong pos) | |
{ | |
| |
lseek(handle, pos, SEEK_SET); | |
} | |
| |
/* | |
* Class: LinuxIoAdapter | |
* Method: sync | |
* Signature: (J)V | |
*/ | |
JNIEXPORT void JNICALL Java_LinuxIoAdapter_sync | |
(JNIEnv *env, jclass jc, jint handle) | |
{ | |
fdatasync(handle); | |
//fsync(handle); | |
} | |
| |
/* | |
* Class: LinuxIoAdapter | |
* Method: write | |
* Signature: (J[BI)V | |
*/ | |
JNIEXPORT void JNICALL Java_LinuxIoAdapter_write | |
(JNIEnv *env, jclass jc, jint handle, jbyteArray bytes, jint length) | |
{ | |
jbyte buf[length]; | |
| |
(*env)->GetByteArrayRegion(env, bytes, 0, length, buf); | |
| |
ssize_t n = write(handle, &buf, length); | |
| |
if(n != length) | |
printf("read failed: %i->%i", length, n); | |
} |
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