This commits adds support for postgres database.
Currently two fields are stored: the bloom filter and the topic.
Only the bloom filter is actually used to query, but potentially we will
use also the topic in the future, so easier to separate it now in order
to avoid a migration.
As part of a performance profiling of mailserver we noticed that most of
the resources on a query are spend decoding the whisper envelope.
This PR changes the way we store envelopes encoding the Topic into the
database key, so we can check that and we are able to publish the
envelope rawValue if it matches.
The change is backward compatible as only newly added envelopes will
have the new key, while old ones will have to be unmarshaled.
MailServer pruning was implemented as a separate command but that required stopping a mail server and executing the command manually. This change builds pruning into MailServer and can be set using MailServerDataRetention in WhisperConfig.
add mailserver cleaner
use memstorage for leveldb in tests
avoid write if batch size is 0
add comments
add cmd/statusd-prune
rmeove batch size var in prune method
validate range values
pass only flag name to missingFlag
refactor Cleaner.prune method
update batch not to be a pointer
removed extra batch counter increment
don't increment counter if batch returns errors
add README
Andrea Maria Piana
Adam Babik
Andrea Franz