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From Jan Høydahl <>
Subject Re: rollback to other versions of index
Date Tue, 15 Feb 2011 09:43:56 GMT
Yes and no. The index grows like an onion adding new segments for each commit.
There is no API to remove the newly added segments, but I guess you could hack something.
The other problem is that as soon as you trigger an optimize() all history is gone as the
segments are merged into one. Optimize normally happens automatically behind the scenes. You
could turn off merging but that will badly hurt your performance after some time and ultimately
crash your OS.

Since you only need a few versions back, you COULD write your own custom mergePolicy, always
preserving at least N versions. But beware that a "version" may be ONE document or 10000 documents,
depending on how you commit or if autoCommit is active. so if you go this route you also need
strict control over your commits.

Perhaps best option is to handle this on feeding client side, where you keep a buffer of N
last docs. Then you can freely roll back or re-index as you choose, based on time, number
of docs etc.

Jan Høydahl, search solution architect
Cominvent AS -

On 15. feb. 2011, at 01.21, Tri Nguyen wrote:

> Hi,
> Does solr version each index build?  
> We'd like to be able to rollback to not just a previous version but maybe a few 
> version before the current one.
> Thanks,
> Tri

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