Hi Jan, As far as I know, Solr only supports circuit breaks for queries at the moment.
We have a custom integration of circuit breakers for indexing (in Solr 8, so that's not fully aligned with what in solr 9) with a custom UpdateRequestProcessor. Basically, a new instance of every update processor is created by calling the corresponding factory. We then check system stats (CPU...) at the first handled doc. Maybe there are other ways of integrating circuit breakers, but at least doing so in an update processor was not intrusive in the code. Probably it is worth it to have something standard in Solr. A "symetric" class of SearchHandler to add CB integration could be UpdateRequestHandler. Pierre Le mar. 27 juin 2023 à 13:32, Jan Høydahl <jan....@cominvent.com> a écrit : > Hi, > > Solr has CPU and Memory circuit breakers that will terminate Search > Requests only. > See > https://solr.apache.org/guide/solr/latest/deployment-guide/circuit-breakers.html > for docs. > > Example: > > <circuitBreaker class="solr.CircuitBreakerManager" enabled="true"> > <str name="memEnabled">true</str> > <str name="memThreshold">75</str> > <str name="cpuEnabled">true</str> > <str name="cpuThreshold">75</str> > </circuitBreaker> > > > A Solr node typically gets overloaded by the combined update and query > traffic, and > I'm looking into enabling ciricuit breakers for update requests. For many > workloads, pausing > update traffic would resolve the situation, with the benefit of users not > being affected by aborted > queries. > > So ideally I'd want to be able to choose to enable/disable CB on > update/query individually. > Or better, to kill update requests on e.g. 80% threshold and search > requests on 90% threshold. > > The current breaker impl for search < > https://github.com/apache/solr/blob/branch_9_2/solr/core/src/java/org/apache/solr/handler/component/SearchHandler.java#L372:380> > [1] is hardcoded into SearchHandler in such a way that if ANY > of the configured breakers trips, search requests are aborted. Also the > breakers seem to be generic > in nature, named CPUCircuitBreaker < > https://github.com/apache/solr/blob/branch_9_2/solr/core/src/java/org/apache/solr/util/circuitbreaker/CPUCircuitBreaker.java> > and MemoryCircuitBreaker < > https://github.com/apache/solr/blob/branch_9_2/solr/core/src/java/org/apache/solr/util/circuitbreaker/MemoryCircuitBreaker.java>, > so adding new UpdateCPUCircuitBreaker > does not seem to be the intention here. > > I'm also unclear on the usefulness of having CB on the core level and not > the node level. If you have > 10 cores from 10 collections on a node, and only some have CBs while > others do not, the node will > still be overloaded unless the admin convinces every collection owner to > implement the same CBs? > > So my question becomes - how do we enable CB for update requests into this > mix in a clean way? > > Jan
