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From Dotan Cohen <>
Subject Re: What exactly happens to extant documents when the schema changes?
Date Wed, 29 May 2013 06:48:24 GMT
On Tue, May 28, 2013 at 2:20 PM, Upayavira <> wrote:
> The schema provides Solr with a description of what it will find in the
> Lucene indexes. If you, for example, changed a string field to an
> integer in your schema, that'd mess things up bigtime. I recently had to
> upgrade a date field from the 1.4.1 date field format to the newer
> TrieDateField. Given I had to do it on a live index, I had to add a new
> field (just using copyfield) and re-index over the top, as the old field
> was still in use. I guess, given my app now uses the new date field
> only, I could presumably reindex the old date field with the new
> TrieDateField format, but I'd want to try that before I do it for real.

Thank you for the insight. Unfortunately, with 20 million records and
growing by hundreds each minute (social media posts) I don't see that
I could ever reindex the data in a timely way.

> However, if you changed a single valued field to a multi-valued one,
> that's not an issue, as a field with a single value is still valid for a
> multi-valued field.
> Also, if you add a new field, existing documents will be considered to
> have no value in that field. If that is acceptable, then you're fine.
> I guess if you remove a field, then those fields will be ignored by
> Solr, and thus not impact anything. But I have to say, I've never tried
> that.
> Thus - changing the schema will only impact on future indexing. Whether
> your existing index will still be valid depends upon the changes you are
> making.
> Upayavira


Dotan Cohen

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