Force create a BASE file (use a foreground `rewriteAppendOnlyFile`) when redis starts from an
empty data set and `appendonly` is yes.
The reasoning is that normally, after redis is running for some time, and the AOF has gone though
a few rewrites, there's always a base rdb file. and the scenario where the base file is missing, is
kinda rare (happens only at empty startup), so this change normalizes it.
But more importantly, there are or could be some complex modules that are started with some
configuration, when they create persistence they write that configuration to RDB AUX fields, so
that can can always know with which configuration the persistence file they're loading was
created (could be critical). there is (was) one scenario in which they could load their persisted data,
and that configuration was missing, and this change fixes it.
Add a new module event: REDISMODULE_SUBEVENT_PERSISTENCE_SYNC_AOF_START, similar to
REDISMODULE_SUBEVENT_PERSISTENCE_AOF_START which is async.
Co-authored-by: Oran Agra <oran@redislabs.com>
there were two lssues, one is taht BGREWRITEAOF failed since the initial one was still in progress
the solution for this one is to enable appendonly from the server startup so there's no initial aofrw.
the other problem was 0 loading progress events, theory is that on some
platforms a sleep of 1 will cause a much greater delay due to the context
switch, but on other platform it doesn't. in theory a sleep of 100 micro
for 1k keys whould take 100ms, and with hz of 500 we should be gettering
50 events (one every 2ms). in practise it doesn't work like that, so trying
to find a sleep that would be long enough but still not cause the test to take
too long.
* replication hooks: role change, master link status, replica online/offline
* persistence hooks: saving, loading, loading progress
* misc hooks: cron loop, shutdown, module loaded/unloaded
* change the way hooks test work, and add tests for all of the above
startLoading() now gets flag indicating what is loaded.
stopLoading() now gets an indication of success or failure.
adding startSaving() and stopSaving() with similar args and role.
