Re: (ITS#7491) mdb write bus error before adding 5 million keys

[hyc@symas.com]

clayton.stangeland@gmail.com wrote:
> Full_Name: Clayton Stangeland
> Version: git mdb.master last commit fed573cb86ed99f37bd062908ec814ee0ca47053
> OS: Fedora 17 64 bit
> URL: ftp://ftp.openldap.org/incoming/mtest-big.c
> Submission from: (NULL) (192.94.73.31)
>
>
> Building and running mdb from git branch mdb.master commit
> fed573cb86ed99f37bd062908ec814ee0ca47053 on Fedora 17 64 bit I get a bus error.

Thanks for the report. The bus error is now fixed in git mdb.master. We assume 
that most users will not batch so many operations into a single transaction.
>
> When running the test below, which is a modification of mtest.c, I get a Bus
> error. This happens while trying to write the file. gdb reports line 3936 of
> mdb.c as the erroring line inside mdb_page_search_root: while (IS_BRANCH(mp)) {
>
> If I set count to 4 million instead of 5 million it works, and adding back in
> all the other mtest.c tests works as well then.
>
> Here is the code:
> /* mtest.c - memory-mapped database tester/toy */
> /*
>   * Copyright 2011 Howard Chu, Symas Corp.
>   * 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>.
>   */
> #define _XOPEN_SOURCE 500               /* srandom(), random() */
> #include <stdio.h>
> #include <stdlib.h>
> #include <time.h>
> #include "lmdb.h"
>
> 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;
>          int count;
>          int *values;
>          char sval[32];
>
>          srandom(time(NULL));
>
>              count = (5000000) + 64;
>              values = (int *)malloc(count*sizeof(int));
>
>              for(i = 0;i<count;i++) {
>                          values[i] = random()%1000000000;
>              }
>
>                  rc = mdb_env_create(&env);
>                  rc = mdb_env_set_mapsize(env, 10485760000);
>                  rc = mdb_env_open(env, "./testdb", MDB_FIXEDMAP /*|MDB_NOSYNC*/,
> 0664);
>                  rc = mdb_txn_begin(env, NULL, 0, &txn);
>                  rc = mdb_open(txn, NULL, 0, &dbi);
>
>                  key.mv_size = sizeof(sval);
>                  key.mv_data = sval;
>                  data.mv_size = sizeof(sval);
>                  data.mv_data = sval;
>
>              for (i=0;i<count;i++) {
>                          sprintf(sval, "%08x %d foo bar", values[i], values[i]);
>                          rc = mdb_put(txn, dbi, &key, &data, MDB_NOOVERWRITE);
>                          if (rc) j++;
>              }
>                  if (j) printf("%d duplicates skipped\n", j);
>                  rc = mdb_txn_commit(txn);
>                  rc = mdb_env_stat(env, &mst);
>
>                  free(values);
>                  mdb_close(env, dbi);
>                  mdb_env_close(env);
>
>          return 0;
>
> }
>
>


-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/