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



Thank you. I did not consider the transaction size.

On 1/11/13, Howard Chu <hyc@symas.com> wrote:
> 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/
>