PIP 81: Split the individual acknowledgments into multiple entries

[315157973]

Motivation

Pulsar persists the individual acknowledgments into Ledger for each subscription.
acknowledgment hole uses guava range to record.
Now a single entry is used to record these holes, but a single entry can not stores more than 5MB data.
Therefore, this PIP stores these holes in different entries separately. And use LRU to ensure low memory usage.
In this way, we can support almost unlimited acknowledgment hole.

Doc: https://docs.google.com/document/d/1uQtyb8t6X04v2vrSrdGWLFkuCkBcGYZbqK8XsVJ4qkU/edit

Modifications

recover:

1. Added API recoverFromMultiEntry
2. The old logic is abstract as recoverFromSingleEntry

persist position to ledger：

1. Add API persistPositionToMultiEntry and saveMarker
2. The old logic is abstract as persistPositionToSingleEntry

when creating new ledger:

1. Add API copyLruEntriesToNewLedger
2. The old logic remains the same

LRU:

1. Add class RangeSetWrapper. Responsible for loading and eliminating of LRU data .
2. The loading of LRU data is synchronous, and elimination of LRU data is asynchronous, with RangeSetWrapper#LruTask

Verifying this change

persist position to ledger has 3 chain:

internalAsyncMarkDelete + NoLedger -> startCreatingNewMetadataLedger -> createNewMetadataLedgerAndSwitch -> doCreateNewMetadataLedger -> persistPositionToLedger -> switchToNewLedger -> flushPendingMarkDeletes -> internalMarkDelete -> persistPositionToLedger -> remove individualDeletedMessages

internalAsyncMarkDelete + Ledger is Open -> internalMarkDelete -> persistPositionToLedger -> remove individualDeletedMessages

persistPositionWhenClosing -> persistPositionToLedger -> close ledger

create new ledger has 1 chain:

initialize -> createNewMetadataLedgerAndSwitch -> doCreateNewMetadataLedger -> switchToNewLedger -> flushPendingMarkDeletes -> internalMarkDelete -> persistPositionToLedger -> remove individualDeletedMessages

recover has 1 chain:

initializeCursors -> recover -> recoverFromLedger -> recoverFromMultiEntry

[Anonymitaet]

@315157973 thanks for your contribution. For this PR, do we need to update docs?

[codelipenghui]

The pr had no activity for 30 days, mark with Stale label.

[tisonkun]

Closed as stale and conflict. Please rebase and resubmit the patch if it's still relevant.