In Tlogs, disable pop is done whlie taking snapshots. Earlier, tlogs
were ignoring the pops if it got pop requests when pops were
disabled. In this change, instead of ignoring the pop - it remembers
the list of pops in-memory and plays them once the popping is
enabled.
- exec operation to go to all the TLogs
- minor bug fix in tlog
- restore implementation for the simulator
- restore snap UID to be stored in restartInfo.ini
- test cases added
- indentation and trace file fixes
fix: we could incorrectly make data durable if eraseMessagesFromMemory was in progress while running updatePersistentData
the quiet database check now ensure that tlogs have no more than 30 seconds of versions unpopped from the disk queue
This deprioritizes before calling peekMessagesFromMemory, which should
improve the memory usage of the TLog, and makes sure to keep txsTag
peeks at a high priority to help recoveries stay fast.
Theoretically, we could spill 20MB of 22B mutations for one key, which
would generate a very long value being stored in SQLite, and very
inefficiently read back. This stops that from being a problem, at the
cost of some extra write calls.
This changes the logic of pop operations from log routers (LG):
- LG pops tagLocalityLogRouterMapped from TLogs;
- TLog converts tagLocalityLogRouterMapped back to tagLocalityLogRouter before
popping.
Later when we add more psuedo localities, the same pattern can be used.
This time, track what location in the DiskQueue has been spilled in
persistent state, and then feed it back into the disk queue before
recovery.
This also introduces an ASSERT that recovery only reads exactly the
bytes that it needs to have in memory.
Popping the disk queue now requires potentially recovering the location
to which we can pop from the spilled data itself, and for each tag we
must maintain the first location with relevant data.
The previous queue we had to represent the ordering, queueOrder, was
used by spilling, and popped when a TLog had been spilled. This means
that as soon as a TLog has been fully spilled, we have no idea how it
relates in order to other fully spilled TLogs.
Instead, use queueOrder to keep track of all the TLog UIDs until they're
removed, and use spillOrder to keep track of the order only for
spilling.
If a server has its data spilled, then it's behind the 5s window.
Feeding it data is less important than committing, so we can hide the
extra CPU usage from checksumming the read amplified disk queue pages.
Though this format is being deprecated in favor of an eventual plumbing
through of TLogVersion, we should probably bump it anyway.
And also remove the fallback to OldTLogServer code. It should never be
executed, as OldTLogServer_6_0 is entirely relied upon to execute
OldTLogServer_4_6.
sramamoorthy