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Merge pull request #23916 from gosubpl/wip/22974-gc-tombstones

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=ddata Garbage collect valueDeltas tombstones at merge/mergeDelta (#22974)
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Patrik Nordwall 2017-12-05 13:19:27 +01:00 • committed by GitHub
commit 74b5866f60
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4 changed files with 43 additions and 30 deletions
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8
akka-distributed-data/src/main/scala/akka/cluster/ddata/ORMap.scala
View file

@ -331,9 +331,13 @@ final class ORMap[A, B <: ReplicatedData] private[akka] (
val mergedValue = thisValue.merge(thatValue.asInstanceOf[thisValue.T]).asInstanceOf[B]
mergedValues = mergedValues.updated(key, mergedValue)
case (Some(thisValue), None) ⇒
mergedValues = mergedValues.updated(key, thisValue)
if (mergedKeys.contains(key))
mergedValues = mergedValues.updated(key, thisValue)
// else thisValue is a tombstone, but we don't want to carry it forward, as the other side does not have the element at all
case (None, Some(thatValue)) ⇒
mergedValues = mergedValues.updated(key, thatValue)
if (mergedKeys.contains(key))
mergedValues = mergedValues.updated(key, thatValue)
// else thatValue is a tombstone, but we don't want to carry it forward, as the other side does not have the element at all
case (None, None) ⇒ throw new IllegalStateException(s"missing value for $key")
}
}

20
akka-distributed-data/src/main/scala/akka/cluster/ddata/ORMultiMap.scala
View file

@ -3,9 +3,9 @@
*/
package akka.cluster.ddata
import akka.cluster.{ Cluster, UniqueAddress }
import akka.annotation.InternalApi
import akka.cluster.ddata.ORMap._
import akka.cluster.{ Cluster, UniqueAddress }
object ORMultiMap {
/**
@ -69,9 +69,12 @@ final class ORMultiMap[A, B] private[akka] (
override def merge(that: T): T =
if (withValueDeltas == that.withValueDeltas) {
if (withValueDeltas)
new ORMultiMap(underlying.mergeRetainingDeletedValues(that.underlying), withValueDeltas)
else
if (withValueDeltas) {
val newUnderlying = underlying.mergeRetainingDeletedValues(that.underlying)
// Garbage collect the tombstones we no longer need, i.e. those that have Set() as a value.
val newValues = newUnderlying.values.filterNot { case (key, value) ⇒ !newUnderlying.keys.contains(key) && value.isEmpty }
new ORMultiMap[A, B](new ORMap(newUnderlying.keys, newValues, newUnderlying.zeroTag, newUnderlying.delta), withValueDeltas)
} else
new ORMultiMap(underlying.merge(that.underlying), withValueDeltas)
} else throw new IllegalArgumentException("Trying to merge two ORMultiMaps of different map sub-type")
@ -253,9 +256,12 @@ final class ORMultiMap[A, B] private[akka] (
override def delta: Option[D] = underlying.delta
override def mergeDelta(thatDelta: D): ORMultiMap[A, B] =
if (withValueDeltas)
new ORMultiMap(underlying.mergeDeltaRetainingDeletedValues(thatDelta), withValueDeltas)
else
if (withValueDeltas) {
val newUnderlying = underlying.mergeDeltaRetainingDeletedValues(thatDelta)
// Garbage collect the tombstones we no longer need, i.e. those that have Set() as a value.
val newValues = newUnderlying.values.filterNot { case (key, value) ⇒ !newUnderlying.keys.contains(key) && value.isEmpty }
new ORMultiMap[A, B](new ORMap(newUnderlying.keys, newValues, newUnderlying.zeroTag, newUnderlying.delta), withValueDeltas)
} else
new ORMultiMap(underlying.mergeDelta(thatDelta), withValueDeltas)
override def modifiedByNodes: Set[UniqueAddress] =

16
akka-distributed-data/src/test/scala/akka/cluster/ddata/ORMultiMapSpec.scala
View file

@ -467,8 +467,8 @@ class ORMultiMapSpec extends WordSpec with Matchers {
val m3 = m1.mergeDelta(m2.delta.get)
val m4 = m1.merge(m2)
m3.underlying.values("a").elements should ===(Set()) // tombstone for 'a' - but we can probably optimize that away, read on
m4.underlying.values("a").elements should ===(Set()) // tombstone for 'a' - but we can probably optimize that away, read on
m3.underlying.values.contains("a") should be(false) // tombstone for 'a' has been optimized away at the end of the mergeDelta
m4.underlying.values.contains("a") should be(false) // tombstone for 'a' has been optimized away at the end of the merge
val m5 = ORMultiMap.emptyWithValueDeltas[String, String].put(node1, "a", Set("A1"))
(m3 mergeDelta m5.delta.get).entries("a") should ===(Set("A1"))
@ -489,8 +489,8 @@ class ORMultiMapSpec extends WordSpec with Matchers {
val um3 = um1.mergeDelta(um2.delta.get)
val um4 = um1.merge(um2)
um3.underlying.values("a").elements should ===(Set()) // tombstone for 'a' - but we can probably optimize that away, read on
um4.underlying.values("a").elements should ===(Set()) // tombstone for 'a' - but we can probably optimize that away, read on
um3.underlying.values.contains("a") should be(false) // tombstone for 'a' has been optimized away at the end of the mergeDelta
um4.underlying.values.contains("a") should be(false) // tombstone for 'a' has been optimized away at the end of the merge
val um5 = ORMultiMap.emptyWithValueDeltas[String, String].addBinding(node1, "a", "A1")
(um3 mergeDelta um5.delta.get).entries("a") should ===(Set("A1"))
@ -518,11 +518,9 @@ class ORMultiMapSpec extends WordSpec with Matchers {
tm3.mergeDelta(tm2.delta.get).entries should ===(Map.empty[String, String]) // no tombstone - update delta could not be applied
tm3.merge(tm2).entries should ===(Map.empty[String, String])
// This situation gives us possibility of removing the impact of tombstones altogether, as the only valid value for tombstone
// created by means of either API call or application of delta propagation would be Set()
// then the tombstones being only empty sets can be entirely cleared up
// because the merge delta operation will use in that case the natural zero from the delta.
// Thus in case of valid API usage and normal operation of delta propagation no tombstones will be created.
// The only valid value for tombstone created by means of either API call or application of delta propagation is Set()
// which is then garbage collected at every `merge` and `mergeDelta` operation.
// Hence in the case of valid API usage and normal operation of delta propagation no tombstones will be permanently created.
}
"have unapply extractor" in {