As per #3043, this adds a ticker to sync the WAL every 2s while the WAL is running.
* Flush WAL every 2s
This adds a ticker that flushes the WAL every 2s while the WAL is
running. This is related to #3043.
* Fix spelling
* Increase timeout to 2mins for slower build environments
* Make WAL sync interval configurable
* Add TODO to replace testChan with more comprehensive testBus
* Remove extraneous debug statement
* Remove testChan in favour of using system time
As per
https://github.com/tendermint/tendermint/pull/3300#discussion_r255886586,
this removes the `testChan` WAL member and replaces the approach with a
system time-oriented one. In this new approach, we keep track of the
system time at which each flush and periodic flush successfully
occurred.
The naming of the various functions is also updated here to be more
consistent with "flushing" as opposed to "sync'ing".
* Update naming convention and ensure lock for timestamp update
* Add Flush method as part of WAL interface
Adds a `Flush` method as part of the WAL interface to enforce the idea
that we can manually trigger a WAL flush from outside of the WAL. This
is employed in the consensus state management to flush the WAL prior to
signing votes/proposals, as per https://github.com/tendermint/tendermint/issues/3043#issuecomment-453853630
* Update CHANGELOG_PENDING
* Remove mutex approach and replace with DI
The dependency injection approach to dealing with testing concerns could
allow similar effects to some kind of "testing bus"-based approach. This
commit introduces an example of this, where instead of relying on
(potentially fragile) timing of things between the code and the test, we
inject code into the function under test that can signal the test
through a channel.
This allows us to avoid the `time.Sleep()`-based approach previously
employed.
* Update comment on WAL flushing during vote signing
Co-Authored-By: thanethomson <connect@thanethomson.com>
* Simplify flush interval definition
Co-Authored-By: thanethomson <connect@thanethomson.com>
* Expand commentary on WAL disk flushing
Co-Authored-By: thanethomson <connect@thanethomson.com>
* Add broken test to illustrate WAL sync test problem
Removes test-related state (dependency injection code) from the WAL data
structure and adds test code to illustrate the problem with using
`WALGenerateNBlocks` and `wal.SearchForEndHeight` to test periodic
sync'ing.
* Fix test error messages
* Use WAL group buffer size to check for flush
A function is added to `libs/autofile/group.go#Group` in order to return
the size of the buffered data (i.e. data that has not yet been flushed
to disk). The test now checks that, prior to a `time.Sleep`, the group
buffer has data in it. After the `time.Sleep` (during which time the
periodic flush should have been called), the buffer should be empty.
* Remove config root dir removal from #3291
* Add godoc for NewWAL mentioning periodic sync
Thane Thomson
dff3deb2a9