Full_Name: Max Bolingbroke
Version: LMDB HEAD
OS: OS X
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (149.254.58.67)
It is possible to insert a (key, value) pair into an MDB_DUPSORTed LMDB database
twice using mdb_cursor_put(..., MDB_CURRENT). If you attempt to insert the same
(key, value) pair twice with mdb_put then the second insert has no effect. This
seems like a bug in mdb_cursor_put.
Furthermore, you can use mdb_cursor_put(..., MDB_CURRENT) to insert duplicates
in the opposite of their correctly sorted order. This is certainly a bug.
The following C program demonstrates both issues:
#define _XOPEN_SOURCE 500
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdarg.h>
#include "lmdb.h"
void panic(const char * restrict format, ...) {
va_list argp;
va_start(argp, format);
vprintf%foformat, argp);
va_end(argp);
exit(1);
}
void mdb_check(char *context, int rc) {
if (rc != 0) {
panic("%s: %s", context, mdb_strerror(rc));
}
}
void mdb_check_notfound(char *context, int rc) {
if (rc != MDB_NOTFOUND) {
panic("%s: %s", context, mdb_strerror(rc));
}
}
int BE(int x) {
return (x & 0x000000FF) << 24 |
(x & 0x0000FF00) << 8 |
(x & 0x00FF0000) >> 8 |
(x & 0xFF000000) >> 24;
}
int main(int argc, char **argv) {
srand(1337);
MDB_e * *env;
mdb_check("mdb_env_create", mdb_env_create(&env));
mdb_check("mdb_env_set_maxdbs", mdb_env_set_maxdbs(env, 1));
mdb_check("mdb_env_set_mapsize", mdb_env_set_mapsize(env, 1024 * 1024));
mdb_check("mdb_env_open", mdb_env_open(env, "testdb", MDB_NOSUBDIR,
0644));
MDB_txn *txn;
mdb_check("mdb_txn_begin", mdb_txn_begin(env, NULL, 0, &txn));
MDB_dbi dbi;
mdb_check("mdb_dbi_open", mdb_dbi_open(txn, "root", MDB_CREATE |
MDB_DUPSORT,
&dbi));
int key;
int value;
MDB_val keyBuffer;
keyBuffer.mv_size = sizeof(int);
keyBuffer.mv_data = &key;
MDB_val valueBuffer;
valueBuffer.mv_size = sizeof(int);
valueBuffer.mv_data = &value;
{
key = BE(2); value = BE(200);
mdb_check("mdb_put", mdb_put(txn, dbi, &keyBuffer,
&valueBuffer, 0));
key = BE(2); value = BE(300);
mdb_check("mdb_put", mdb_put(txn, dbi, &keyBuffer,
&valueBuffer, 0));
// Inserting the same (key, value) pair twice: second insert is
ignored
key = BE(2); value = BE(300);
mdb_check("mdb_put", mdb_put(txn, dbi, &keyBuffer,
&valueBuffer, 0));
}
{
MDB_cursor *cursor;
mdb_check("mdb_cursor_open", mdb_cursor_open(txn, dbi,
&cursor));
size_t count;
mdb_check("mdb_cursor_get", mdb_cursor_get(cursor, &keyBuffer,
&valueBuffer,
MDB_FIRST))0D0D
mdb_check("mdb_cursor_count", mdb_cursor_count(cursor, &count));
if (count != 2) panic("count != 2");
if (0) {
// Inserting the same (key, value) pair twice: second
insert is not ignored.
// While this is different to mdb_put, I can't tell
from the docs whether
this is a bug or not.
keyBuffer.mv_size = sizeof(int); valueBuffer.mv_size =
sizeof(int);
keyBuffer.mv_data = &key; valueBuffer.mv_data = &value;
key = BE(2); value = BE(300);
mdb_check("mdb_cursor_put2,2C mdb_cursor_put(cursor,
&keyBuffer,
&valueBuffer, MDB_CURRENT));
mdb_check("mdb_cursor_count", mdb_cursor_count(cursor,
&count));
if (count != 1) panic("count != 1");
} else {
// This on the other hand is definitely a bug: after
doing this the
duplicates are not sorted.
keyBuffer.mv_size = sizeof(int); valueBuffer.mv_size =
sizeof(int);
keyBuffer.mv_data = &key; valueBuffer.mv_data = &value;
key = BE(2); value = BE(400);
mdb_check("mdb_cursor_put", mdb_cursor_p(c8cursor,
&keyBuffer, &valueBuffer,
MDB_CURRENT));
mdb_check("mdb_cursor_count", mdb_cursor_count(cursor,
&count));
if (count != 2) panic("count != 2");
mdb_check("mdb_cursor_get", mdb_cursor_get(cursor,
&keyBuffer, &valueBuffer,
MDB_FIRST));
printf("%d\n", BE(*((int*)valueBuffer.mv_data)));
mdb_check("mdb_cursor_get", mdb_cursor_get(cursor,
&keyBuffer, &valueBuffer,
MDB_NEXT));
printf("%d\n", BE(*((int*)valueBuffer.mv_data)));
mdb_check_notfound("mdb_cursor_get",
mdb_cursor_get(cursor, &keyBuffer,
&valueBuffer, MDB_NEXT));
}
mdb_cursor_close(cursor);
}
mdb_check("mdb_txn_commit", mdb_txn_commit(txn));
return 0;
}
