If I understand your question correctly .. it’s single-threaded with regard to a specific shard - but you can run multiple shard splitting operations in parallel IFF they affect different shards (or different collections).
See SplitShardCmd for the details of locking and how the new sub-shards are initialised and replicated. Part of the shard splitting always runs asynchronously, namely the part where the new sub-shards are replicated and recovered, and only once this part is done the new sub-shards become active and the old parent shard becomes inactive. You can find this code in ReplicaMutator.checkAndCompleteShardSplit. > On 17 Sep 2019, at 09:51, Antczak, Lukasz <lukasz.antc...@roche.com> wrote: > > Hello, > I have short question to Solr experts. > Is shard split operation single- or multi- threaded? > > Regards > Łukasz Antczak > > -- > *Łukasz Antczak* > Senior IT Professional > GS Data Frontiers Team <http://go.roche.com/bigs> > > *Planned absences:* > *11th August - 18th August* > *26th August - 1st September* > *Roche Polska Sp. z o.o.* > ADMD Group Services - Business Intelligence Team > HQ: ul. Domaniewska 39B, 02-672 Warszawa > Office: ul. Abpa Baraniaka 88D, 61-131 Poznań > > Mobile: +48 519 515 010 > mailto: lukasz.antc...@roche.com > > *Informacja o poufności: *Treść tej wiadomości zawiera informacje > przeznaczone tylko dla adresata. Jeżeli nie jesteście Państwo jej > adresatem, bądź otrzymaliście ją przez pomyłkę, prosimy o powiadomienie o > tym nadawcy oraz trwałe jej usunięcie. Wszelkie nieuprawnione > wykorzystanie informacji zawartych w tej wiadomości jest zabronione. > > *Confidentiality Note:* This message is intended only for the use of the > named recipient(s) and may contain confidential and/or proprietary > information. If you are not the intended recipient, please contact the > sender and delete this message. Any unauthorized use of the information > contained in this message is prohibited.
