To better distribute the memory allocating to indexing, the IndexingMemoryController periodically checks the different shard for their last indexing activity. If no activity has happened for a while, the controller marks the shards as in active and allocated it's memory buffer budget (but a small minimal budget) to other active shards. The recently added synced flush feature (#11179, #11336) uses this inactivity trigger to attempt as a trigger to attempt adding a sync id marker (which will speed up future recoveries).
We wait for 30m before declaring a shard inactive. However, these days the operation just requires a refresh and is light. We can be stricter (and 5m) increase the chance a synced flush will be triggered.
Closes#11479
#10032 introduced the notion of sealing an index by marking it with a special read only marker, allowing for a couple of optimization to happen. The most important one was to speed up recoveries of shards where we know nothing has changed since they were online by skipping the file based sync phase. During the implementation we came up with a light notion which achieves the same recovery benefits but without the read only aspects which we dubbed synced flush. The fact that it was light weight and didn't put the index in read only mode, allowed us to do it automatically in the background which has great advantage. However we also felt the need to allow users to manually trigger this operation.
The implementation at #11179 added the sync flush internal logic and the manual (rest) rest API. The name of the API was modeled after the sealing terminology which may end up being confusing. This commit changes the API name to match the internal synced flush naming, namely `{index}/_flush/synced'.
On top of that it contains a couple other changes:
- Remove all java client API. This feature is not supposed to be called programtically by applications but rather by admins.
- Improve rest responses making structure similar to other (flush) API
- Change IndexShard#getOperationsCount to exclude the internal +1 on open shard . it's confusing to get 1 while there are actually no ongoing operations
- Some minor other clean ups
The `full` option and `FlushType.NEW_WRITER` only exists to allow
realtime changes to two settings (`index.codec` and `index.concurrency`).
Those settings are very expert and don't really need to be updateable
in realtime.
This commit adds the ability to force blocking on the flush operaition
to make sure all files have been written and synced to disk. Without
this option a flush might be executing at the same time causing the
current flush to fail and return before all files being synced.
Closes#6996
* Clean up s/ElasticSearch/Elasticsearch on docs/*
* Clean up s/ElasticSearch/Elasticsearch on src/* bin/* & pom.xml
* Clean up s/ElasticSearch/Elasticsearch on NOTICE.txt and README.textile
Closes#4634
Refresh flag in flush is problematic, since the shards refresh is allowed to execute on is different compared to the flush shards. In order to do flush and then refresh, they should be executed as separate APIs when needed.
closes#3689
Clinton Gormley
Boaz Leskes
Simon Willnauer
Shay Banon