Re: Question about link-walk results returned by erlang_pb_client

2014-03-16 Thread fxmy wang 
Hi Alex,

Thank you for the clarify( and the warning :) ).

Just out of curiosity, by using erlang_pb_client, is there a good way
to retrieve *all* the Objects that have been walked in on shot( like
the HTTP interface does)?

And if there's not, then how is the HTTP map-reduce implemented so
that it can return all the Objects alone the way?

Best Regards :)
fxmy

2014-03-15 0:30 GMT+08:00 Alex Moore amo...@basho.com:
 Hi fxmy,

 The return value is just Bucket/Key/link-tag pairs, without ObjectValue or
 other metadata.

 {ok,[{0,[[people,timoreilly,friend]]},

 {1,[[people,dhh,friend]]}]}


 Is this intended or not?


 This is intended.  You are running a map reduce job with one link stage,
 which does the link walking for you.
 Link stages only return a list of key/value/relation tuples.

 If so, what's the best way to get these ObjectValues through one single pass
 of link-walking?


 If you want to grab everything in one shot you would have to feed the link
 stage's output into a map stage to grab the actual objects:

 {ok, RiakObj} = riakc_pb_socket:mapred(Pid,[{people,
 timoreilly}],
 [{link, people, friend, false},
  {link, people, friend, false},
  {map, {modfun, riak_kv_mapreduce, map_identity}, none, true}]).

 This should give you the entire object for the results of the last link
 phase, namely Dave Thomas's.

 I should warn you thought that while link walking and map reduce let you do
 things like this in one shot, you should be cautious about using them in
 production since a bad query can kill performance.

 Thanks,
 Alex

 On Mar 14, 2014, at 6:49 AM, fxmy wang fxm...@gmail.com wrote:


 Hi, list,

 This should be a trivial question and I think I'm definitely missing
 something( and feeling stupid :\).

 So when I am doing a chained link-walking through HTTP interface like
 this(copied from link walking docs):

 curl -v localhost:8091/riak/people/davethomas/_,friend,1/_,friend,_/


 The output is quite verbose, including Bucket/Key/Value etc.etc.

 --JCgqdOHsL4BdXPCb0cuQDnLTxOH

 Content-Type: multipart/mixed; boundary=LpfqXc9urbAJJNFH7aGGPBiAtnX


 --LpfqXc9urbAJJNFH7aGGPBiAtnX

 X-Riak-Vclock: a85hYGBgzGDKBVIcc+04TgWFOj/NYEpkzGNlyNCadoYvCwA=

 Location: /riak/people/timoreilly

 Content-Type: text/plain

 Link: /riak/people/dhh; riaktag=friend, /riak/people; rel=up

 Etag: 3DmGNeyDj2hUlLR2UhJvMr

 Last-Modified: Thu, 13 Mar 2014 13:11:04 GMT


 I am an excellent public speaker.

 --LpfqXc9urbAJJNFH7aGGPBiAtnX--


 --JCgqdOHsL4BdXPCb0cuQDnLTxOH

 Content-Type: multipart/mixed; boundary=IcBLyeIFObvJlJGyXuhTty5cRSs


 --IcBLyeIFObvJlJGyXuhTty5cRSs

 X-Riak-Vclock: a85hYGBgzGDKBVIcR4M2cgeFOkdkMCUy5rEyzNSadoYvCwA=

 Location: /riak/people/dhh

 Content-Type: text/plain

 Link: /riak/people; rel=up

 Etag: 4qbA2ZufXNgzFRb8PlSLUO

 Last-Modified: Thu, 13 Mar 2014 13:11:53 GMT


 I drive a Zonda.

 --IcBLyeIFObvJlJGyXuhTty5cRSs--


 --JCgqdOHsL4BdXPCb0cuQDnLTxOH--



 But when I retried it through the erlang_pb_client

 riakc_pb_socket:mapred(Pid,[{people, davethomas}],[{link,
 people, friend, true},{link, people, friend,
 true}]).


 The return value is just Bucket/Key/link-tag pairs, without ObjectValue or
 other metadata.

 {ok,[{0,[[people,timoreilly,friend]]},

 {1,[[people,dhh,friend]]}]}


 Is this intended or not?
 If so, what's the best way to get these ObjectValues through one single pass
 of link-walking?


 Cheers,
 ___
 riak-users mailing list
 riak-users@lists.basho.com
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Question about link-walk results returned by erlang_pb_client

2014-03-14 Thread fxmy wang 
Hi, list,

This should be a trivial question and I think I'm definitely missing
something( and feeling stupid :\).

So when I am doing a chained link-walking through HTTP interface like
this(copied
from link walking
docshttp://docs.basho.com/riak/latest/dev/using/link-walking/
):

 curl -v localhost:8091/riak/people/davethomas/_,friend,1/_,friend,_/


The output is quite verbose, including Bucket/Key/Value etc.etc.

 --JCgqdOHsL4BdXPCb0cuQDnLTxOH

Content-Type: multipart/mixed; boundary=LpfqXc9urbAJJNFH7aGGPBiAtnX


 --LpfqXc9urbAJJNFH7aGGPBiAtnX

X-Riak-Vclock: a85hYGBgzGDKBVIcc+04TgWFOj/NYEpkzGNlyNCadoYvCwA=

Location: /riak/people/timoreilly

Content-Type: text/plain

Link: /riak/people/dhh; riaktag=friend, /riak/people; rel=up

Etag: 3DmGNeyDj2hUlLR2UhJvMr

Last-Modified: Thu, 13 Mar 2014 13:11:04 GMT


 I am an excellent public speaker.

--LpfqXc9urbAJJNFH7aGGPBiAtnX--


 --JCgqdOHsL4BdXPCb0cuQDnLTxOH

Content-Type: multipart/mixed; boundary=IcBLyeIFObvJlJGyXuhTty5cRSs


 --IcBLyeIFObvJlJGyXuhTty5cRSs

X-Riak-Vclock: a85hYGBgzGDKBVIcR4M2cgeFOkdkMCUy5rEyzNSadoYvCwA=

Location: /riak/people/dhh

Content-Type: text/plain

Link: /riak/people; rel=up

Etag: 4qbA2ZufXNgzFRb8PlSLUO

Last-Modified: Thu, 13 Mar 2014 13:11:53 GMT


 I drive a Zonda.

--IcBLyeIFObvJlJGyXuhTty5cRSs--


 --JCgqdOHsL4BdXPCb0cuQDnLTxOH--



But when I retried it through the erlang_pb_client

 riakc_pb_socket:mapred(Pid,[{people, davethomas}],[{link,
 people, friend, true},{link, people, friend,
 true}]).


The return value is just Bucket/Key/link-tag pairs, without ObjectValue or
other metadata.

 {ok,[{0,[[people,timoreilly,friend]]},

{1,[[people,dhh,friend]]}]}


Is this intended or not?
If so, what's the best way to get these ObjectValues through one single
pass of link-walking?


Cheers,
___
riak-users mailing list
riak-users@lists.basho.com
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Re: Question about link-walk results returned by erlang_pb_client

2014-03-14 Thread Alex Moore 
Hi fxmy,

 The return value is just Bucket/Key/link-tag pairs, without ObjectValue or 
 other metadata.
 {ok,[{0,[[people,timoreilly,friend]]},
 {1,[[people,dhh,friend]]}]}
 
 Is this intended or not?

This is intended.  You are running a map reduce job with one “link” stage, 
which does the link walking for you.   
Link stages only return a list of key/value/relation tuples.

 If so, what's the best way to get these ObjectValues through one single pass 
 of link-walking?

If you want to grab everything in one shot you would have to feed the link 
stage’s output into a map stage to grab the actual objects:

{ok, RiakObj} = riakc_pb_socket:mapred(Pid,[{people, timoreilly}],
[{link, people, friend, false},
 {link, people, friend, false}, 
 {map, {modfun, riak_kv_mapreduce, map_identity}, none, true}]).

This should give you the entire object for the results of the last link phase, 
namely Dave Thomas’s.

I should warn you thought that while link walking and map reduce let you do 
things like this in one shot, you should be cautious about using them in 
production since a bad query can kill performance.  

Thanks,
Alex

On Mar 14, 2014, at 6:49 AM, fxmy wang fxm...@gmail.com wrote:

 
 Hi, list,
 
 This should be a trivial question and I think I'm definitely missing 
 something( and feeling stupid :\).
 
 So when I am doing a chained link-walking through HTTP interface like 
 this(copied from link walking docs):
 curl -v localhost:8091/riak/people/davethomas/_,friend,1/_,friend,_/
  
 The output is quite verbose, including Bucket/Key/Value etc.etc.
 --JCgqdOHsL4BdXPCb0cuQDnLTxOH
 Content-Type: multipart/mixed; boundary=LpfqXc9urbAJJNFH7aGGPBiAtnX
 
 --LpfqXc9urbAJJNFH7aGGPBiAtnX
 X-Riak-Vclock: a85hYGBgzGDKBVIcc+04TgWFOj/NYEpkzGNlyNCadoYvCwA=
 Location: /riak/people/timoreilly
 Content-Type: text/plain
 Link: /riak/people/dhh; riaktag=friend, /riak/people; rel=up
 Etag: 3DmGNeyDj2hUlLR2UhJvMr
 Last-Modified: Thu, 13 Mar 2014 13:11:04 GMT
 
 I am an excellent public speaker.
 --LpfqXc9urbAJJNFH7aGGPBiAtnX--
 
 --JCgqdOHsL4BdXPCb0cuQDnLTxOH
 Content-Type: multipart/mixed; boundary=IcBLyeIFObvJlJGyXuhTty5cRSs
 
 --IcBLyeIFObvJlJGyXuhTty5cRSs
 X-Riak-Vclock: a85hYGBgzGDKBVIcR4M2cgeFOkdkMCUy5rEyzNSadoYvCwA=
 Location: /riak/people/dhh
 Content-Type: text/plain
 Link: /riak/people; rel=up
 Etag: 4qbA2ZufXNgzFRb8PlSLUO
 Last-Modified: Thu, 13 Mar 2014 13:11:53 GMT
 
 I drive a Zonda.
 --IcBLyeIFObvJlJGyXuhTty5cRSs--
 
 --JCgqdOHsL4BdXPCb0cuQDnLTxOH--
 
 
 But when I retried it through the erlang_pb_client
 riakc_pb_socket:mapred(Pid,[{people, davethomas}],[{link, 
 people, friend, true},{link, people, friend, true}]).
  
 The return value is just Bucket/Key/link-tag pairs, without ObjectValue or 
 other metadata.
 {ok,[{0,[[people,timoreilly,friend]]},
 {1,[[people,dhh,friend]]}]}
 
 Is this intended or not?
 If so, what's the best way to get these ObjectValues through one single pass 
 of link-walking?
 
 
 Cheers,
 ___
 riak-users mailing list
 riak-users@lists.basho.com
 http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com

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