Some clarifications :
1) *lots of docs, few queries* : If you have a high number of documents
(+dozen millions) and lowish number of queries per second (say less than
10), replicas will not help to reduce the Qtime. For this kind of task
it is better to shard the index, as each query will effectively be
processed in parallel by N shards, thus reducing Qtime.
2) *few docs, lots of queries* : less than 10M docs and 30+ qps, on the
contrary, you want more replicas to handle more traffic, and avoid
overloaded servers (which would increase the Qtime).
3) *lots of docs, lots of queries* : do both sharding and replicas.
Actual numbers depends on the hardware, the type of docs and queries, etc.
The best is to benchmark your setup varying the load so that you case
trace a hockey stick graph of Qtime versus qps.
Feel free to ask for details if needed.
André
On 05/07/2013 01:56 PM, Stanislav Sandalnikov wrote:
Hi Yan,
Thanks for the quick reply.
Thus, replication seems to be the preferable solution. QTime decreases
proportional to replications number or there are any other drawbacks?
Just to clarify, what amount of documents stands for "tons of documents" in
your opinion? :)
2013/5/7 Jan Høydahl<jan....@cominvent.com>
Hi,
It depends(TM) on what kind of search performance problems you are seeing.
If you simply have so high query load that the server starts to kneal, it
will
definitely not help to shard, since ALL the shards will still be hit with
ALL the queries, and you add some extra overhead with sharding as well.
But if your QPS is moderate and you have tons of documents, you may gain
better performance both for indexing latency and search latency by
sharding.
--
Jan Høydahl, search solution architect
Cominvent AS - www.cominvent.com
7. mai 2013 kl. 13:09 skrev Stanislav Sandalnikov<s.sandalni...@gmail.com
:
Hi,
We are moving to SolrCloud architecture. And I have question about search
performance and its correlation with shards or replicas. What will be
more
efficient: to split all index we have to several shards or create several
replications of index? Is parallel search works with both shards and
replicas?
Please share your experience regarding this matter.
Thanks in advance.
Regards,
Stanislav
--
André Bois-Crettez
Search technology, Kelkoo
http://www.kelkoo.com/
Kelkoo SAS
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