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PIP-404: Introduce per-ledger properties

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PIP-404: Introduce per-ledger properties

Background knowledge

As we don't have a secondary index on the Bookkeeper, so we can't query entries by message metadata efficiently. The ManagedCursor provides a method asyncFindNewestMatching to find the newest entry that matches the given predicate by binary search(See OpFindNewest.java). In https://github.com/apache/pulsar/pull/22792, we optimized seeking by timestamp by calculating the range of ledgers that may contain the target timestamp by LedgerInfo#timestamp and we don't need to scan all ledgers.

However, when we enabled AppendIndexMetadataInterceptor and we want to query entries by BrokerEntryMetadata#index, there is no more efficient way, we have to scan all ledgers by binary search to find the target entry.

Motivation

Introduce per-ledger properties and we can store the extra per-ledger properties in the LedgerInfo, so we can query entries by incremental index more efficiently, say, BrokerEntryMetadata#index.

Goals

In Scope

  • Provide a way to set per-ledger properties, it should be a generic way and can be used by any plugin.

Out of Scope

  • Set extra per-ledger properties, it should be done by the specific plugin. Such as KoP.

High Level Design

We can store the incremental index of the first entry in the ledger into LedgerInfo#properties, say, BrokerEntryMetadata#index. When we want to query entries by BrokerEntryMetadata#index, we can calculate the range of ledgers that may contain the target index by LedgerInfo#properties and we don't need to scan all ledgers.

In https://github.com/apache/pulsar/pull/22792, we provided a new method to find the newest entry with given range of entries:

java
void asyncFindNewestMatching(FindPositionConstraint constraint, Predicate<Entry> condition,
                                 Position startPosition, Position endPosition, FindEntryCallback callback,
                                 Object ctx, boolean isFindFromLedger) {
    }

We can use this method directly in the above scenario.

Detailed Design

Public-facing Changes

Public API

  • Add the following method in ManagedLedger:
java
    CompletableFuture<Void> asyncAddLedgerProperty(long ledgerId, String key, String value);
    CompletableFuture<Void> asyncRemoveLedgerProperty(long ledgerId, String key);

Binary protocol

  • Add a new field properties in LedgerInfo:
protobuf
message LedgerInfo {
      required int64 ledgerId = 1;
      optional int64 entries = 2;
      optional int64 size = 3;
      optional int64 timestamp = 4;
      optional OffloadContext offloadContext = 5;
      // Add the following field
      repeated KeyValue properties = 6;
}

Backward & Forward Compatibility

It is fully backward compatible.

Alternatives

None

Links

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