Hello Anshum,
In my case i have to add /modify records to the current index database and
there will be only delete in older index DB. I will not have a situitation
of updating the older records.
Please brief me about your requirement and how you configured your database.
Whether you have any incremental updates??
What have gained by sharding the index.
Regards
Ganesh
----- Original Message -----
From: "Anshum" <[EMAIL PROTECTED]>
To: <java-user@lucene.apache.org>
Sent: Tuesday, October 07, 2008 5:55 PM
Subject: Re: Single searcher vs Multi Searcher
There were all of the links I could find:
http://findmeajob.wordpress.com/2007/07/31/lucene-singlesearcher-vs-multisearcher/
http://archives.devshed.com/forums/java-118/how-do-lucene-ids-work-with-multireader-and-multisearcher-993682.html
It has been only out of personal experimentation.
Maintaining 4 indexes and having a multisearcher for the same sounds ok to
me, though it might(most probably would) use up more time (depending on
your
term/doc distribution).
I have tried multisearchers for indexes that are sized at around 18Gs with
over 10 million records in them and they seem to be working fine. Memory
utilization hasn't really been my problem though maintenance has been
required to be taken care of if I had record updates as well i.e.
Lets assume we have 4 indexes {1,2,3,4} with 4 being the oldest one. Now a
document got updated and so you would want to move it to the freshest
index
viz. index 1. In this case you would also have to delete this document
from
index 4 (after figuring out that it exists in 4) else this doc would show
up
as 2 hits using a multisearcher.
This is the document movement that I was talking about.
Talking only about online resource utilization ( as what I just spoke
about
is generally an offline process), you would have to spend extra resource
to
merge the hits from the different indexes.
The other overhead in case of a multisearcher would be of creating those
many searchers - for each index(though shouldn't be much, just though
would
point out).
I guess you should try it as speed of search is not realy all that
important
to you as compared to running it on a singe box within the memory
limitation.
--
Anshum Gupta
Naukri Labs!
http://ai-cafe.blogspot.com
The facts expressed here belong to everybody, the opinions to me. The
distinction is yours to draw............
On Tue, Oct 7, 2008 at 3:29 PM, Ganesh <[EMAIL PROTECTED]> wrote:
Hello Anusham,
My intention is to shard the index after every 7 days (week). After 30
days, (4th week) the first DB may get deleted. At any point of time i
will
be maitaining 3 to 4 DB.
I want to know the pros and cons of the MultiSearcher or Index sharding
approach. Any web links would be helpful.
Regards
Ganesh
----- Original Message ----- From: "Anshum" <[EMAIL PROTECTED]>
To: <java-user@lucene.apache.org>
Sent: Tuesday, October 07, 2008 12:18 AM
Subject: Re: Single searcher vs Multi Searcher
Hi Ganesh,
About the memory consumption while sorting, it would end up using
similar
amounts, perhaps even more.. like in the case of regular parallel
programming algorithms (hoping that you intend to search using a
parallel
multi searcher). Would you have to query particular indexes only for a
particular search or would you be searching over all the indexes and
then
follow it up by merger (which the parallel multi searcher would do
efficiently).?
Also, I guess 30 indexes would be a little too many, haven't really
tried
out those many indexes for a multisearcher.
As far as maintenance of DB is concerned, it might be easy as long as
you
don't have any document updates, in which case you'd have to shift the
documents from one DB/index to another (which includes creating an entry
in
the latest index/DB and deleting the record from the older DB).
I guess you'd have to pilot it, in case memory is an issue in your case
and
not speed, you could try a regular multisearcher instead of a parallel
multisearcher.
I guess when you say maintenance of the DB gets easier, you mean that
the
data in each individual table is controlled (but remember there could be
other bigger hassles like the one mentioned above about moving data
between
indexes/DB).
--
Anshum Gupta
Naukri Labs!
http://ai-cafe.blogspot.com
The facts expressed here belong to everybody, the opinions to me. The
distinction is yours to draw............
On Mon, Oct 6, 2008 at 10:06 AM, Ganesh <[EMAIL PROTECTED]> wrote:
Hello Anshum,
My index is growing 1 million documents per day. Initially i planned to
have a single database but the sorting of one or more fields consumes
more
RAM. Whether sharding the index would also consume the same.
My application should co-exist with other application of my product and
my
app could get 1 GB of RAM. Search speed is fine but i need to display
the
result in the sorted order.
I thought to keep 7 days of documents in one index and create one more
after the 7 days. After 30 days the first index may get deleted. I need
to
keep the documents in the index DB for 30 days. My Index DB is in HDD.
I want to the pros and cons of sharding. I think maintance of the DB
becomes easier.
It would be very much helpful, if you share some of your thoughts.
Regards
Ganesh
----- Original Message ----- From: "Anshum" <[EMAIL PROTECTED]>
To: <java-user@lucene.apache.org>
Sent: Friday, October 03, 2008 9:48 PM
Subject: Re: Single searcher vs Multi Searcher
Hi Ganesh,
I have experimented with sharded indexes and they seem to benefit
me(atleast
in my case). I would like to know a few things before I answer your
question:
1. Do you have a reasonable criteria ( a calculated one) to shard the
indexes?
2. How do you plan to split the index? Is it going to be document
based
(which I guess it should be as otherwise you would have to build a
complete
distributed system)
3. Do you plan to put your indexes on the RAM or on (physically)
seperate
HDDs?
Though all said and done, sharded indexes are a good approach, if done
the
right way.
--
Anshum Gupta
Naukri Labs!
http://ai-cafe.blogspot.com
The facts expressed here belong to everybody, the opinions to me. The
distinction is yours to draw............
On Fri, Oct 3, 2008 at 3:01 PM, Ganesh <[EMAIL PROTECTED]> wrote:
Hello all,
My indexing is growing by 1 million records per day and the memory
consumption of the searcher object is quite high.
There are different opinion in the groups. Few suggest to use single
database and few to use sharding. My Database has 10 million records
now
and
it might go till 30 million or more. I plan to shard the index. but
Multisearcher will give me benifit.
Regards
Ganesh
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