M hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
Rather than compound the pause time, just have backoff multiple the
original INIT_PAUSE_TIME_MS so we go 1, 2, 5, 10, ... etc. rather than
1, 2, 30, 600... and so on.
Minor fixup around logging so report of failed transition is no longer
reported as trace-level.
Added support for configuring read/write timeouts on a per-table basis
when in region mode.
Added unit test for per-table timeout checks.
Signed-off-by: Andrew Purtell <apurtell@apache.org>
This doc. keeps state on where we are at w/ the new AM:
https://docs.google.com/document/d/1eVKa7FHdeoJ1-9o8yZcOTAQbv0u0bblBlCCzVSIn69g/edit#heading=h.vfdoxqut9lqn
Includes list of tests disabled by this patch with reasons why.
Based on patches from Matteos' repository and then fix up to get it all to pass cluster
tests, filling in some missing functionality, fix of findbugs, fixing bugs, etc..
including:
1. HBASE-14616 Procedure v2 - Replace the old AM with the new AM.
The basis comes from Matteo's repo here:
689227fcbf
Patch replaces old AM with the new under subpackage master.assignment.
Mostly just updating classes to use new AM -- import changes -- rather
than the old. It also removes old AM and supporting classes.
See below for more detail.
2. HBASE-14614 Procedure v2 - Core Assignment Manager (Matteo Bertozzi)
3622cba4e3
Adds running of remote procedure. Adds batching of remote calls.
Adds support for assign/unassign in procedures. Adds version info
reporting in rpc. Adds start of an AMv2.
3. Reporting of remote RS version is from here:
ddb4df3964.patch
4. And remote dispatch of procedures is from:
186b9e7c4d
5. The split merge patches from here are also melded in:
9a3a95a2c2
and d6289307a0
We add testing util for new AM and new sets of tests.
Does a bunch of fixup on logging so its possible to follow a procedures' narrative by grepping
procedure id. We spewed loads of log too on big transitions such as master fail; fixed.
Fix CatalogTracker. Make it use Procedures doing clean up of Region data on split/merge.
Without these changes, ITBLL was failing at larger scale (3-4hours 5B rows) because we were
splitting split Regions among other things (CJ would run but wasn't
taking lock on Regions so havoc).
Added a bunch of doc. on Procedure primitives.
Added new region-based state machine base class. Moved region-based
state machines on to it.
Found bugs in the way procedure locking was doing in a few of the
region-based Procedures. Having them all have same subclass helps here.
Added isSplittable and isMergeable to the Region Interface.
Master would split/merge even though the Regions still had
references. Fixed it so Master asks RegionServer if Region
is splittable.
Messing more w/ logging. Made all procedures log the same and report
the state the same; helps when logging is regular.
Rewrote TestCatalogTracker. Enabled TestMergeTableRegionProcedure.
Added more functionality to MockMasterServices so can use it doing
standalone testing of Procedures (made TestCatalogTracker use it
instead of its own version).
Add to MasterServices ability to wait on Master being up -- makes
it so can Mock Master and start to implement standalone split testing.
Start in on a Split region standalone test in TestAM.
Fix bug where a Split can fail because it comes in in the middle of
a Move (by holding lock for duration of a Move).
Breaks CPs that were watching merge/split. These are run by Master now
so you need to observe on Master, not on RegionServer.
Details:
M hbase-client/src/main/java/org/apache/hadoop/hbase/ClusterStatus.java
Takes List of regionstates on construction rather than a Set.
NOTE!!!!! This is a change in a public class.
M hbase-client/src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
Add utility getShortNameToLog
M hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionImplementation.java
M hbase-client/src/main/java/org/apache/hadoop/hbase/client/ShortCircuitMasterConnection.java
Add support for dispatching assign, split and merge processes.
M hbase-client/src/main/java/org/apache/hadoop/hbase/master/RegionState.java
Purge old overlapping states: PENDING_OPEN, PENDING_CLOSE, etc.
M hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/Procedure.java
Lots of doc on its inner workings. Bug fixes.
M hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/ProcedureExecutor.java
Log and doc on workings. Bug fixes.
A hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/RemoteProcedureDispatcher.java
Dispatch remote procedures every 150ms or 32 items -- which ever
happens first (configurable). Runs a timeout thread. This facility is
not on yet; will come in as part of a later fix. Currently works a
region at a time. This class carries notion of a remote procedure and of a buffer full of these.
"hbase.procedure.remote.dispatcher.threadpool.size" with default = 128
"hbase.procedure.remote.dispatcher.delay.msec" with default = 150ms
"hbase.procedure.remote.dispatcher.max.queue.size" with default = 32
M hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java
Add in support for merge. Remove no-longer used methods.
M hbase-protocol-shaded/src/main/protobuf/Admin.proto b/hbase-protocol-shaded/src/main/protobuf/Admin.proto
Add execute procedures call ExecuteProcedures.
M hbase-protocol-shaded/src/main/protobuf/MasterProcedure.proto
Add assign and unassign state support for procedures.
M hbase-server/src/main/java/org/apache/hadoop/hbase/client/VersionInfoUtil.java
Adds getting RS version out of RPC
Examples: (1.3.4 is 0x0103004, 2.1.0 is 0x0201000)
M hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java
Remove periodic metrics chore. This is done over in new AM now.
Replace AM with the new. Host the procedures executor.
M hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterMetaBootstrap.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterMetaBootstrap.java
Have AMv2 handle assigning meta.
M hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterRpcServices.java
Extract version number of the server making rpc.
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/AssignProcedure.java
Add new assign procedure. Runs assign via Procedure Dispatch.
There can only be one RegionTransitionProcedure per region running at the time,
since each procedure takes a lock on the region.
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/AssignCallable.java
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/AssignmentManager.java
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/BulkAssigner.java
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/GeneralBulkAssigner.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/GeneralBulkAssigner.java
Remove these hacky classes that were never supposed to live longer than
a month or so to be replaced with real assigners.
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/RegionStateStore.java
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/RegionStates.java
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/UnAssignCallable.java
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/AssignmentManager.java
A procedure-based AM (AMv2).
TODO
- handle region migration
- handle meta assignment first
- handle sys table assignment first (e.g. acl, namespace)
- handle table priorities
"hbase.assignment.bootstrap.thread.pool.size"; default size is 16.
"hbase.assignment.dispatch.wait.msec"; default wait is 150
"hbase.assignment.dispatch.wait.queue.max.size"; wait max default is 100
"hbase.assignment.rit.chore.interval.msec"; default is 5 * 1000;
"hbase.assignment.maximum.attempts"; default is 10;
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/MoveRegionProcedure.java
Procedure that runs subprocedure to unassign and then assign to new location
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStateStore.java
Manage store of region state (in hbase:meta by default).
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStates.java
In-memory state of all regions. Used by AMv2.
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionTransitionProcedure.java
Base RIT procedure for Assign and Unassign.
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/UnassignProcedure.java
Unassign procedure.
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/RSProcedureDispatcher.java
Run region assignement in a manner that pays attention to target server version.
Adds "hbase.regionserver.rpc.startup.waittime"; defaults 60 seconds.
Move to a new AssignmentManager, one that describes Assignment using
a State Machine built on top of ProcedureV2 facility.
This doc. keeps state on where we are at w/ the new AM:
https://docs.google.com/document/d/1eVKa7FHdeoJ1-9o8yZcOTAQbv0u0bblBlCCzVSIn69g/edit#heading=h.vfdoxqut9lqn
Includes list of tests disabled by this patch with reasons why.
Based on patches from Matteos' repository and then fix up to get it all to pass cluster
tests, filling in some missing functionality, fix of findbugs, fixing bugs, etc..
including:
1. HBASE-14616 Procedure v2 - Replace the old AM with the new AM.
The basis comes from Matteo's repo here:
689227fcbf
Patch replaces old AM with the new under subpackage master.assignment.
Mostly just updating classes to use new AM -- import changes -- rather
than the old. It also removes old AM and supporting classes.
See below for more detail.
2. HBASE-14614 Procedure v2 - Core Assignment Manager (Matteo Bertozzi)
3622cba4e3
Adds running of remote procedure. Adds batching of remote calls.
Adds support for assign/unassign in procedures. Adds version info
reporting in rpc. Adds start of an AMv2.
3. Reporting of remote RS version is from here:
ddb4df3964.patch
4. And remote dispatch of procedures is from:
186b9e7c4d
5. The split merge patches from here are also melded in:
9a3a95a2c2
and d6289307a0
We add testing util for new AM and new sets of tests.
Does a bunch of fixup on logging so its possible to follow a procedures' narrative by grepping
procedure id. We spewed loads of log too on big transitions such as master fail; fixed.
Fix CatalogTracker. Make it use Procedures doing clean up of Region data on split/merge.
Without these changes, ITBLL was failing at larger scale (3-4hours 5B rows) because we were
splitting split Regions among other things (CJ would run but wasn't
taking lock on Regions so havoc).
Added a bunch of doc. on Procedure primitives.
Added new region-based state machine base class. Moved region-based
state machines on to it.
Found bugs in the way procedure locking was doing in a few of the
region-based Procedures. Having them all have same subclass helps here.
Added isSplittable and isMergeable to the Region Interface.
Master would split/merge even though the Regions still had
references. Fixed it so Master asks RegionServer if Region
is splittable.
Messing more w/ logging. Made all procedures log the same and report
the state the same; helps when logging is regular.
Rewrote TestCatalogTracker. Enabled TestMergeTableRegionProcedure.
Added more functionality to MockMasterServices so can use it doing
standalone testing of Procedures (made TestCatalogTracker use it
instead of its own version).
Add to MasterServices ability to wait on Master being up -- makes
it so can Mock Master and start to implement standalone split testing.
Start in on a Split region standalone test in TestAM.
Fix bug where a Split can fail because it comes in in the middle of
a Move (by holding lock for duration of a Move).
Breaks CPs that were watching merge/split. These are run by Master now
so you need to observe on Master, not on RegionServer.
Details:
M hbase-client/src/main/java/org/apache/hadoop/hbase/ClusterStatus.java
Takes List of regionstates on construction rather than a Set.
NOTE!!!!! This is a change in a public class.
M hbase-client/src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
Add utility getShortNameToLog
M hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionImplementation.java
M hbase-client/src/main/java/org/apache/hadoop/hbase/client/ShortCircuitMasterConnection.java
Add support for dispatching assign, split and merge processes.
M hbase-client/src/main/java/org/apache/hadoop/hbase/master/RegionState.java
Purge old overlapping states: PENDING_OPEN, PENDING_CLOSE, etc.
M hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/Procedure.java
Lots of doc on its inner workings. Bug fixes.
M hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/ProcedureExecutor.java
Log and doc on workings. Bug fixes.
A hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/RemoteProcedureDispatcher.java
Dispatch remote procedures every 150ms or 32 items -- which ever
happens first (configurable). Runs a timeout thread. This facility is
not on yet; will come in as part of a later fix. Currently works a
region at a time. This class carries notion of a remote procedure and of a buffer full of these.
"hbase.procedure.remote.dispatcher.threadpool.size" with default = 128
"hbase.procedure.remote.dispatcher.delay.msec" with default = 150ms
"hbase.procedure.remote.dispatcher.max.queue.size" with default = 32
M hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java
Add in support for merge. Remove no-longer used methods.
M hbase-protocol-shaded/src/main/protobuf/Admin.proto b/hbase-protocol-shaded/src/main/protobuf/Admin.proto
Add execute procedures call ExecuteProcedures.
M hbase-protocol-shaded/src/main/protobuf/MasterProcedure.proto
Add assign and unassign state support for procedures.
M hbase-server/src/main/java/org/apache/hadoop/hbase/client/VersionInfoUtil.java
Adds getting RS version out of RPC
Examples: (1.3.4 is 0x0103004, 2.1.0 is 0x0201000)
M hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java
Remove periodic metrics chore. This is done over in new AM now.
Replace AM with the new. Host the procedures executor.
M hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterMetaBootstrap.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterMetaBootstrap.java
Have AMv2 handle assigning meta.
M hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterRpcServices.java
Extract version number of the server making rpc.
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/AssignProcedure.java
Add new assign procedure. Runs assign via Procedure Dispatch.
There can only be one RegionTransitionProcedure per region running at the time,
since each procedure takes a lock on the region.
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/AssignCallable.java
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/AssignmentManager.java
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/BulkAssigner.java
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/GeneralBulkAssigner.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/GeneralBulkAssigner.java
Remove these hacky classes that were never supposed to live longer than
a month or so to be replaced with real assigners.
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/RegionStateStore.java
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/RegionStates.java
D hbase-server/src/main/java/org/apache/hadoop/hbase/master/UnAssignCallable.java
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/AssignmentManager.java
A procedure-based AM (AMv2).
TODO
- handle region migration
- handle meta assignment first
- handle sys table assignment first (e.g. acl, namespace)
- handle table priorities
"hbase.assignment.bootstrap.thread.pool.size"; default size is 16.
"hbase.assignment.dispatch.wait.msec"; default wait is 150
"hbase.assignment.dispatch.wait.queue.max.size"; wait max default is 100
"hbase.assignment.rit.chore.interval.msec"; default is 5 * 1000;
"hbase.assignment.maximum.attempts"; default is 10;
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/MoveRegionProcedure.java
Procedure that runs subprocedure to unassign and then assign to new location
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStateStore.java
Manage store of region state (in hbase:meta by default).
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStates.java
In-memory state of all regions. Used by AMv2.
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionTransitionProcedure.java
Base RIT procedure for Assign and Unassign.
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/UnassignProcedure.java
Unassign procedure.
A hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/RSProcedureDispatcher.java
Run region assignement in a manner that pays attention to target server version.
Adds "hbase.regionserver.rpc.startup.waittime"; defaults 60 seconds.
It should be the normal case that HBase automatically deletes
quotas for deleted tables. Switch the Observer to be on by
default and add an option to instead prevent it from being added.
Most notable change is to cache SpaceViolationPolicyEnforcement objects
in the write path. When a table has no quota or there is not SpaceQuotaSnapshot
for that table (yet), we want to avoid creating lots of
SpaceViolationPolicyEnforcement instances, caching one instance
instead. This will help reduce GC pressure.
When a table or namespace is deleted, it would be nice to automatically
delete the quota on said table/NS. It's possible that not all people
would want this functionality so we can leave it up to the user to
configure this Observer.
A couple of variables and comments in which violation is incorrectly
used to describe what the code is doing. This was a hold over from early
implementation -- need to scrub these out for clarity.
* Expire region reports in the master after a timeout.
* Move regions in violation out of violation when insufficient
region size reports are observed.
The logic surrounding when a table and namespace quota both apply
to a table was incorrect, leading to a case where a table quota
violation which should have fired did not because of the less-strict
namespace quota.
Create some RPCs that can expose the in-memory state that the
RegionServers and Master hold to drive the space quota "state machine".
Then, create some hbase shell commands to interact with those.
The nuts-and-bolts of filesystem quotas. The Master must inform
RegionServers of the violation of a quota by a table. The RegionServer
must apply the violation policy as configured. Need to ensure
that the proper interfaces exist to satisfy all necessary policies.
This required a massive rewrite of the internal tracking by
the general space quota feature. Instead of tracking "violations",
we need to start tracking "usage". This allows us to make the decision
at the RegionServer level as to when the files in a bulk load request
should be accept or rejected which ultimately lets us avoid bulk loads
dramatically exceeding a configured space quota.
* Implement the RegionServer reading violation from the quota table
* Implement the Master reporting violations to the quota table
* RegionServers need to track its enforced policies
Adds a new Chore to the Master that analyzes the reports that are
sent by RegionServers. The Master must then, for all tables with
quotas, determine the tables that are violating quotas and move
those tables into violation. Similarly, tables no longer violating
the quota can be moved out of violation.
The Chore is the "stateful" bit, managing which tables are and
are not in violation. Everything else is just performing
computation and informing the Chore on the updated state.
Added InterfaceAudience annotations and clean up the QuotaObserverChore
constructor. Cleaned up some javadoc and QuotaObserverChore. Reuse
the QuotaViolationStore impl objects.
- internalRestoreSnapshot() returns future which completes by just getting proc_id from master. Changed it to wait for the procedure to complete.
- Refactor TestAsyncSnapshotAdminApi: Add cleanup() which deletes all tables and snapshots after every test run. Simplifies individual tests.
Change-Id: Idc30fb699db32d58fd0f60da220953a430f1d3cc
Test was failing on clusters with large number of servers or regions. Using commonly using config settings like some other tests seems to work.
Signed-off-by: Michael Stack <stack@apache.org>
The default behavior for abort() method of StateMachineProcedure is changed to support aborting all procedures irrespective of if rollback is supported or not. Currently its observed that sometimes procedures may fail on a step which will be considered as retryable error as abort is not supported. As a result procedure may stuck in a endless loop repeating same step again.User should have an option to abort any stuck procedure and do clean up manually. Please refer to HBASE-18016 and discussion there.
Signed-off-by: Michael Stack <stack@apache.org>
Reason for flakyness: Current test is probability based fault injection and triggers failure 3% of the time. Earlier when test used LocalJobRunner which didn't honor "mapreduce.map.maxattempts", it'd pass 97% time (when no fault is injected) and fail 3% time (when fault was injected). Point being, even when the test was complete wrong, we couldn't catch it because it was probability based.
This change will inject fault in a deterministic manner.
On design side, it encapsulates all testing hooks in ExportSnapshot.java into single inner class.
Change-Id: Icba866e1d56a5281748df89f4dd374bc45bad249
Make test tighter by extending ServerListener so can find when Master
is in the waiting-on-regionservers state and making more assertions
about state.
Fix error where I would move on from waiting-on-regionservers if
we had waited max time.
This patch reverts HBASE-9593 -- i.e. registering in zk before we
register with master putting it back to how it was where we register
in zk AFTER we report for duty with the master (because then we'll
register in zk with the name the master gave us). It then fixes the
problem reported in HBASE-9593 in an alternate fashion by checking
for a RS znode if we failed a connect on assign; if none found, we
remove a server from online servers list.
M hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java
Make move method available to tests.
M hbase-server/src/main/java/org/apache/hadoop/hbase/master/ServerManager.java
Correct method name changing moveFromOnelineToDeadServers to
moveFromOnlineToDeadServers
Add actual fix which is call to checkForRSznode if exception trying to
open a region; if none found, call expire on the server so it gets
removed from the list of online servers.
This patch exposes sloppyness in the waitForRegionServers around our
current case where Master is hosting regions but ONLY hbase:meta;
in this case we need to wait on at least another server to report
in beyond Master (we weren't but stuff was 'working' because of the
early registration of RS nodes in zk).
M hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
Make 'killed' available to tests.
Put registry of ephemeral node back to where it was originally,
so it is AFTER we get response from Master on registering for duty
so we can put our znode up in zk with the name the Master gave us
rather than local name (which could be unknown to the Master).
private boolean stopping = false;
M hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestRSKilledWhenInitializing.java
Cleanup and test of new cleanup.
Earlier when queues had locks, clearQueue() also cleaned up old locks when AbstractProcedureScheduler.clear() was called to reset scheduler for testing failure and recovery.
Now with locks decoupled from queues, they need to be separately cleaned up.
We can't have clearLocks() as abstract method in AbstractProcedureScheduler because at that level, a procedure scheduler is just a queue. It's only in MasterProcedureScheduler that locks come into picture. So directly overriding clear() method in MPS.
Earlier when queues had locks, clearQueue() also cleaned up old locks when AbstractProcedureScheduler.clear() was called.
Now with locks decoupled from queues, they need to be separately cleaned up.
We can't have clearLocks() as abstract method in AbstractProcedureScheduler because at that level, a procedure scheduler is just a queue. It's only in MasterProcedureScheduler that locks come into picture. So directly overriding clear() method in MPS.
Change-Id: If1a0acb418a79f98ce6155541edb0c1e621638e3
Reason for refactor:
In cases where one might need to use multiple observers, say region, master and regionserver; and the fact that only one class can be extended, it gives rise to following pattern:
public class BaseMasterAndRegionObserver
extends BaseRegionObserver
implements MasterObserver
class AccessController
extends BaseMasterAndRegionObserver
implements RegionServerObserver
were BaseMasterAndRegionObserver is full copy of BaseMasterObserver.
There is an example of simple case too where the current design fails.
Say only one observer is needed by the coprocessor, but the design doesn't permit extending even that single observer (see RSGroupAdminEndpoint), that leads to copy of full Bas
e...Observer class into coprocessor class leading to 1000s of lines of code and this ugly mix of 5 main functions with 100 useless functions.
Javadocs changes:
- Adds class comments on 'default' methods and expectations.
- Adds explanaiton of Exception handling in Observers' class comment. Removes redundant @throws before each function.
- Improves javadocs for a bunch of functions
- deletes empty @params in a bunch of places
Change-Id: I265738d47e8554e7b4678e88bb916a0cc7d00ab3
Currently whenever a compaction/bulkload happen and the
blocks are evicted from theirs buckets the buckets become
fragmented and are not available to be used by other
BucketSizes
Bug Fix : Added Memory block type also to the list of
evictions that need to happen when there is a needForExtra
Improvement : Inorder to fix the non availabilty of Buckets and force
the movement of buckets to transformed sizes, whenever we encounter a
situation where an allocation cant be made for a BucketSize, we will
forcefully free the entire buckets that have least occupancy ratio. This
is the same strategy used by MemCached when they encounter a similar
issue going by the name 'Slab Calcification'. Only improvement is that
we use a heuristic to evict from the buckets that are least occupied
and also avoid the BucketSizes where there is a single Bucket
Change-Id: I9e3b4deb8d893953003ddf5f1e66312ed97ea9cb
Signed-off-by: Ramkrishna <ramkrishna.s.vasudevan@intel.com>