Snapshot and restore segments

[laurentiusoica]

Hello,

I have a few questions regarding the ES snapshot feature. I am not able to find a proper answer in the ES documentation so maybe someone could shed some light:

• does a snapshot include uncommitted segments as well ?
• does a snapshot includes non-searchable segments as well ?
• does a snapshot include the segments available at snapshot start time only or segments created during snapshot as well ?
• for a restore over an existing cluster what happens to the data indexed after the snapshot was taken, Is it removed or a merge happens between snapshot data and cluster data ?

Thanks

[ywelsch (Yannick Welsch)]

does a snapshot include uncommitted segments as well ?

starting a snapshot will do a flush (i.e. Lucene commit), so you'll only get committed segments.

does a snapshot includes non-searchable segments as well ?

yes

does a snapshot include the segments available at snapshot start time only or segments created during snapshot as well ?

it includes the segments available at the time that the snapshot starts on the shard

for a restore over an existing cluster what happens to the data indexed after the snapshot was taken, Is it removed or a merge happens between snapshot data and cluster data ?

It is removed, i.e, we restore exactly what's in the snapshot.