Computes the broadcast messages that are stable; i.e., have been received by all members. Sends
STABLE events up the stack when this is the case. This allows NAKACK to garbage collect messages that
have been seen by all members.
Works as follows: periodically we mcast our highest seqnos (seen for each member) to the group.
A stability vector, which maintains the highest seqno for each member and initially contains no data,
is updated when such a message is received. The entry for a member P is computed set to
min(entry[P], digest[P]). When messages from all members have been received, a stability
message is mcast, which causes all members to send a STABLE event up the stack (triggering garbage collection
in the NAKACK layer).
The stable task now terminates after max_num_gossips if no messages or view changes have been sent or received
in the meantime. It will resume when messages are received. This effectively suspends sending superfluous
STABLE messages in the face of no activity.
New: when
max_bytes
is exceeded (unless disabled by setting it to 0),
a STABLE task will be started (unless it is already running).
getDesiredAverageGossip
public long getDesiredAverageGossip()
getMaxBytes
public long getMaxBytes()
getNumberOfGossipMessages
public int getNumberOfGossipMessages()
runMessageGarbageCollection
public void runMessageGarbageCollection()
setDesiredAverageGossip
public void setDesiredAverageGossip(long gossip_interval)
setMaxBytes
public void setMaxBytes(long max_bytes)
start
public void start()
throws Exception
- start in interface Protocol