Separate UIDs and Revisions in main databases

Summary:
- Change revision type from `qint64` to `size_t` for LMDB in a couple of places (LMDB supports `unsigned int` or `size_t` which are `long unsigned int` on my machine)
- Better support for database flags (duplicate, integer keys, integer values for now but is extensible)
- Main databases' keys are now revisions
- Some databases switched to integer keys databases:
  - Main databases
  - the revision to uid mapping database
  - the revision to entity type mapping database
- Refactor the entity type's `typeDatabases` method (if in the future we need to change the main databases' flags again)
- New uid to revision mapping database (`uidsToRevisions`):
  - Stores all revisions (not uid to latest revision) because we need it for cleaning old revisions
  - Flags are: duplicates + integer values (so findLatest finds the latest revision for the given uid)

~~Problems to fix before merging:~~
All Fixed!

- ~~Sometimes Sink can't read what has just been written to the database (maybe because of transactions race conditions)~~
  - ~~Most of the times, this results in Sink not able to find the uid for a given revision by reading the `revisions` database~~
- ~~`pipelinetest`'s `testModifyWithConflict` fails because the local changes are overridden~~

~~The first problem prevents me from running benchmarks~~

Reviewers: cmollekopf

Tags: #sink

Differential Revision: https://phabricator.kde.org/D14974

1 files changed, 3 insertions, 4 deletions

diff --git a/common/changereplay.cpp b/common/changereplay.cpp
index d7f46dc..96162b8 100644
--- a/common/changereplay.cpp
+++ b/common/changereplay.cpp
@@ -116,16 +116,15 @@ KAsync::Job<void> ChangeReplay::replayNextRevision()
                         } else {
                             // TODO: should not use internal representations
                             const auto key = Storage::Key(Storage::Identifier::fromDisplayByteArray(uid), revision);
-                            const auto internalKey = key.toInternalByteArray();
                             const auto displayKey = key.toDisplayByteArray();
                             QByteArray entityBuffer;
                             DataStore::mainDatabase(mMainStoreTransaction, type)
-                                .scan(internalKey,
-                                    [&entityBuffer](const QByteArray &key, const QByteArray &value) -> bool {
+                                .scan(revision,
+                                    [&entityBuffer](const size_t, const QByteArray &value) -> bool {
                                         entityBuffer = value;
                                         return false;
                                     },
-                                    [this, key](const DataStore::Error &) { SinkErrorCtx(mLogCtx) << "Failed to read the entity buffer " << key; });
+                                    [this, key](const DataStore::Error &e) { SinkErrorCtx(mLogCtx) << "Failed to read the entity buffer " << key << "error:" << e; });
 
                             if (entityBuffer.isEmpty()) {
                                 SinkErrorCtx(mLogCtx) << "Failed to replay change " << key;