Your email is slightly confusing - I assume by "paging" you mean "pagination"? I recommend not trying to do pagination in Riak.
I can't help you at all with your custom map/reduce phase code in
trend_riak.erl without seeing vm.args, trend_riak.erl, &c...
On Aug 9, 2012, at 7:27 PM, 郎咸武 wrote:
> Who can answer me? thanks.
>
> 2012/8/10 郎咸武 <langxian...@gmail.com>
> Hi guys,
> How to do a paging in MapReduce queries?
> I try to write some method in the module(trend_riak.erl, Add -pa
> /home/jason/work/server/trunk/trend_riak to vm.args).
> I thought it will well, but unfortunately it does not work. Becase the
> "Reduce" ,the result is wrong.
> Is there the other methods? Thanks.
>
> Cheers Jason
>
> 121 get_reduce_bucket_values(Records, {Start, Max}) ->
> 122 Skip = get_skip_num(Start, Max),
> 123 io:format("get_reduce_bucket_values Records=~p Skip= ~p~n",
> [length(Records), Skip]),
>
> 124 if length(Records) >= Skip ->
> 125 %%NewList = lists:keysort(#pubsub_item.published, Records),
> 126 F = fun(#pubsub_item{published=Published1, level=Level1},
> 127 #pubsub_item{published=Published2, level=Level2}) ->
> 128 if Level1 > Level2 -> true;
> 129 Level1 == Level2 ->
> 130 if Published1 > Published2 -> true;
> 131 true -> false
> 132 end;
> 133 true -> false
> 134 end
> 135 end,
> 136 NewList = lists:sort(F, Records),
> 137 R = lists:sublist(NewList, Skip, Max),
> 138 io:format("get_reduce_bucket_value R=~p Skip= ~p~n",
> [length(R), skip]),
> 139 R;
> 140 true ->
> 141 []
> 142 %Records
> 143 end.
>
>
> --
> 只为成功找方法，不为失败找理由
>
>
>
> --
> 只为成功找方法，不为失败找理由
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