Datastore has a non-zero chance of failing on reads. A map-reduce with too many
failures will eventually give up. As a result, any map-reduce that goes over a
large number of datastore entities is almost guaranteed to fail.
Since we expect to have a large number of EppResources, we make sure to wrap
all datastore reads with some retrying mechanism to reduce the number of
transient failures that propagate to Map-Reduce.
This feature already existed for CommitLogManifestReader, we refactor the code to use the same retrying mechanism in EppResource readers.
Also removed the transactNew around the reads because looking at the source - it doesn't actually do anything we need (doesn't retry on any failure other than concurrency failure)
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=190633281
This change replaces all Ref objects in the code with Key objects. These are
stored in datastore as the same object (raw datastore keys), so this is not
a model change.
Our best practices doc says to use Keys not Refs because:
* The .get() method obscures what's actually going on
- Much harder to visually audit the code for datastore loads
- Hard to distinguish Ref<T> get()'s from Optional get()'s and Supplier get()'s
* Implicit ofy().load() offers much less control
- Antipattern for ultimate goal of making Ofy injectable
- Can't control cache use or batch loading without making ofy() explicit anyway
* Serialization behavior is surprising and could be quite dangerous/incorrect
- Can lead to serialization errors. If it actually worked "as intended",
it would lead to a Ref<> on a serialized object being replaced upon
deserialization with a stale copy of the old value, which could potentially
break all kinds of transactional expectations
* Having both Ref<T> and Key<T> introduces extra boilerplate everywhere
- E.g. helper methods all need to have Ref and Key overloads, or you need to
call .key() to get the Key<T> for every Ref<T> you want to pass in
- Creating a Ref<T> is more cumbersome, since it doesn't have all the create()
overloads that Key<T> has, only create(Key<T>) and create(Entity) - no way to
create directly from kind+ID/name, raw Key, websafe key string, etc.
(Note that Refs are treated specially by Objectify's @Load method and Keys are not;
we don't use that feature, but it is the one advantage Refs have over Keys.)
The direct impetus for this change is that I am trying to audit our use of memcache,
and the implicit .get() calls to datastore were making that very hard.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=131965491
The dark lord Gosling designed the Java package naming system so that
ownership flows from the DNS system. Since we own the domain name
registry.google, it seems only appropriate that we should use
google.registry as our package name.
This change renames directories in preparation for the great package
rename. The repository is now in a broken state because the code
itself hasn't been updated. However this should ensure that git
correctly preserves history for each file.
2016-05-13 18:55:08 -04:00
Renamed from java/com/google/domain/registry/mapreduce/inputs/EppResourceEntityReader.java (Browse further)
