This commit adds the ability to start a transaction with an exclusive
lock for the entire database. This ensures no other read or write
transactions can run at the same time. Writes in this mode write
directly to the database and skip the WAL entirely.
- introduce Query Context (Qcx) for managing database-per-shard.
- replaces the MultiTx, so mtx.go is retired and removed.
- introduces the HolderConfig struct and all Holders now have
a path from birth.
- rbf speedups on bitwise writes
- badgerdb is removed due to unresolvable write conflicts.
fixes#703#676
- rbf had races around the new rootRecords cache in tx
- rbf tx needed a write lock on the db now that rootRecords are written
- added a global registry for rbfDB to correctly dedup instances
- implement DeleteFragment, DeleteIndex for rbf
- use badger style keys for rbf to allow content checksumming to be list
containers in the same order
- lots of other integration of rbf into pilosa layer.
Previously, the `checkpoint()` function determined the segments to drop
based on the current active transactions' WAL ID references. However, if
no transactions are active then the checkpoint would drop segments too
aggressively.
This changes the determination by using the highest WAL ID that is
actually checkpointed to disk to determine the high water mark. If no
page are checkpointed then no segments can be dropped.
green:
TestFragment_RowsIteration/combinations
TestFragment_RoaringImportTopN
red: (needs Ben's attention)
PILOSA_TXSRC=rbf go test -v -run TestFragment_TopN_IDs -tags=' shardwidth20' "-gcflags=all=-d=checkptr=0"
also red: (one for Ben)
TestCursor_FirstNext_Quick/9 is throwing
panic: cannot find segment containing WAL page: 1
as we check the error back from checkpoint() in Rollback().
