No, that should not trigger Jackson parsing. Schema.parse() and Protocol.parse() do.
On 6/2/11 10:23 AM, "ey-chih chow" <[email protected]<mailto:[email protected]>> wrote: We create GenericData.Record a lot in our code via new GenericData.Record(schema). Will this generates Jackson calls? Thanks. Ey-Chih Chow > From: [email protected]<mailto:[email protected]> > To: [email protected]<mailto:[email protected]> > Date: Wed, 1 Jun 2011 18:48:15 -0700 > Subject: Re: avro object reuse > > One thing we do right now that might be related is the following: > > We keep Avro default Schema values as JsonNode objects. While traversing > the JSON Avro schema representation using ObjectMapper.readTree() we > remember JsonNodes that are "default" properties on fields and keep them > on the Schema object. > If these keep references to the parent (and the whole JSON tree, or worse, > the ObjectMapper and input stream) it would be poor use of Jackson by us; > although we'd need a way to keep a detached JsonNode or equivalent. > > However, even if that is the case (which it does not seem to be -- the > jmap output has no JsonNode instances), it doesn't explain why we would be > calling ObjectMapper frequently. We only call > ObjectMapper.readTree(JsonParser) when creating a Schema from JSON. We > call JsonNode methods from extracted fragments for everything else. > > > This brings me to the following suspicion based on the data: > Somewhere, Schema objects are being created frequently via one of the > Schema.parse() or Protocol.parse() static methods. > > On 6/1/11 5:48 PM, "Tatu Saloranta" > <[email protected]<mailto:[email protected]>> wrote: > > >On Wed, Jun 1, 2011 at 5:45 PM, Scott Carey > ><[email protected]<mailto:[email protected]>> > >wrote: > >> It would be useful to get a 'jmap -histo:live' report as well, which > >>will > >> only have items that remain after a full GC. > >> > >> However, a high churn of short lived Jackson objects is not expected > >>here > >> unless the user is reading Json serialized files and not Avro binary. > >> Avro Data Files only contain binary encoded Avro content. > >> > >> It would be surprising to see many Jackson objects here if reading Avro > >> Data Files, because we expect to use Jackson to parse an Avro schema > >>from > >> json only once or twice per file. After the schema is parsed, Jackson > >> shouldn't be used. A hundred thousand DeserializationConfig instances > >> means that isn't the case. > > > >Right -- it indicates that something (else) is using Jackson; and > >there will typically be one instance of DeserializationConfig for each > >data-binding call (ObjectMapper.readValue()), as a read-only copy is > >made for operation. > >... or if something is reading schema that many times, that sounds > >like a problem in itself. > > > >-+ Tatu +- >
