[erlang-bugs] mnesia-4.3.5 select continuation problem

Paul Mineiro <>
Sun Dec 9 05:51:12 CET 2007


by the way, my immediate problem goes away if i just remove the offending
guard (so i'm good for today!).  however i have no idea if this is the
correct way to fix the problem.

-------
% diff -u ets.erl.orig ets.erl
--- ets.erl.orig        2007-12-08 20:48:53.000000000 -0800
+++ ets.erl     2007-12-08 20:48:55.000000000 -0800
@@ -88,7 +88,7 @@
 % ordered_set
 repair_continuation(Untouched = {Table,Lastkey,L1,N2,Bin,L2,N3,N4}, MS)
when
 (is_atom(Table) or is_integer(Table)),
-is_list(L1),
+%is_list(L1),
 is_integer(N2),
 is_binary(Bin),
 size(Bin) =:= 0,

-------

-- p

On Sat, 8 Dec 2007, Paul Mineiro wrote:

> mnesia:select/4 and mnesia:select/1 are failing with ordered set tables
> and a tuple key pattern.  a little module demonstrating the effect is
> attached, the output (on my machine) is:
>
> -------
> 21> c (selectbug), selectbug:showbug ().
> {a,'$1'} set: {atomic,'$end_of_table'}
> {a,'$1'} ordered_set: {'EXIT',
>                           {{badmatch,
>                                {aborted,
>                                    {badarg,
>                                        [ram_copies,
>                                         {bug,{a,b},{a,'$1'},1,<<>>,[],0,0},
>                                         [{{'_',{a,'$1'},'_'},[],['$1']}]]}}},
>                            [{selectbug,selector,2},
>                             {selectbug,'-showbug/0-fun-0-',1},
>                             {lists,foreach,2},
>                             {erl_eval,do_apply,5},
>                             {shell,exprs,6},
>                             {shell,eval_loop,3}]}}
> {a,'$1'} bag: {atomic,'$end_of_table'}
> '$1' set: {atomic,'$end_of_table'}
> '$1' ordered_set: {atomic,'$end_of_table'}
> '$1' bag: {atomic,'$end_of_table'}
> ok
> -------
>
> looking at things, it looks like ets:repair_continuation/2 is expecting
> a list in the 3rd element of the first argument.  i put an io:format on
> the { badrpc, Reason } clause of mnesia:do_dirty_rpc/5 to print out the
> reason:
>
> -------
> {'EXIT',{function_clause,[{ets,repair_continuation,
>                                [{bug,{a,b},{a,'$1'},1,<<>>,[],0,0},
>                                 [{{'_',{a,'$1'},'_'},[],['$1']}]]},
>                           {mnesia_lib,db_select_cont,3},
>                           {rpc,local_call,3},
>                           {mnesia,do_dirty_rpc,5},
>                           {mnesia,select_cont,3},
>                           {mnesia_tm,apply_fun,3},
>                           {mnesia_tm,execute_transaction,5},
>                           {selectbug,selector,2}]}}
> ------
>
> the 3rd element is a tuple here.
>
> poking around i can see that the ets:select/3 call from
> mnesia_lib:db_select_init/4 is actually returning a continuation whose 3rd
> argument is not a list.  this is now a BIF so i feel a bit stuck at this
> point.  since it's a BIF here's some extra info:
>
> ------
> % erl -s erlang halt
> Erlang (BEAM) emulator version 5.5.5 [source] [async-threads:0] [kernel-poll:false]
>
> % dpkg -s erlang-otp
> Package: erlang-otp
> Status: install ok installed
> Priority: optional
> Section: languages
> Installed-Size: 139084
> Maintainer: None <>
> Architecture: darwin-i386
> Source: erlang-otp
> Version: 11b-5-1
> Depends: libncurses5-shlibs, unixodbc2-shlibs | unixodbc2-nox-shlibs, darwin (>= 8-1)
> Description: General-purpose programming language
>  Erlang is a general-purpose programming language and runtime environment.
>  Erlang has built-in support for concurrency, distribution and fault
>  tolerance. Erlang is used in several large telecommunication systems
>  from Ericsson.  The most popular implementation of Erlang is available as
>  open source from the open source erlang site.
>  .
>  Web site: http://www.erlang.org/
>  .
>  Maintainer: None <>
> BuildDependsOnly: Undefined
>
> % uname -a
> Darwin paul-mineiros-computer.local 8.9.3 Darwin Kernel Version 8.9.3: Fri Apr 27 14:50:07 PDT 2007; root:xnu-792.19.5~2/RELEASE_I386 i386 i386
>
> ------
>
> thanks,
>
> -- p
>
> Optimism is an essential ingredient of innovation. How else can the
> individual favor change over security?
>
>   -- Robert Noyce

Optimism is an essential ingredient of innovation. How else can the
individual favor change over security?

  -- Robert Noyce



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