Updates in this context are individual documents, either new ones or a new version of an existing document. Long recoveries are quite unlikely to be replaying a few documents from the tlog.
My bet is that you had to do a “full sync” (there should be messages to that effect in the Solr log). This means that the replica had to copy the entire index from the leader, and that varies with the size of the index, network speed and contention, etc. And to make it more complicated, and despite the comment about 100 docs and the tlog…. while that copy is going on, _new_ updates are written to the tlog of the recovering replica and after the index has been copied, those new updates are replayed locally. The 100 doc limit does _not_ apply in this case. So say the recovery starts at time T and lasts for 60 seconds. All updates sent to the shard leader over that 60 seconds are put in the local tlog and after the copy is done, they’re replayed. And then, you guessed it, any updates received by the leader over that 60 second period are written to the recovering replica’s tlog and replayed… Under heavy indexing loads, this can go no for quite a long time. Not certain that’s what’s happening, but something to be aware of. Best, Erick > On Dec 10, 2019, at 10:39 PM, Hongxu Ma <inte...@outlook.com> wrote: > > Hi all > In my cluster, Solr node turned into long time recovery sometimes. > So I want to know more about recovery and have read a good blog: > https://lucidworks.com/post/understanding-transaction-logs-softcommit-and-commit-in-sorlcloud/ > > It mentioned in the recovery section: > "Replays the documents from its own tlog if < 100 new updates have been > received by the leader. " > > My question: what's the meaning of "updates"? commits? or documents? > I refered solr code but still not sure about it. > > Hope you can help, thanks. >
