athanatos commented on a change in pull request #1931: (WIP)
GetListOfEntriesOfLedger implementation
URL: https://github.com/apache/bookkeeper/pull/1931#discussion_r253229693
##########
File path:
bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/InterleavedLedgerStorage.java
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@@ -641,4 +649,233 @@ public void onRotateEntryLog() {
public List<GarbageCollectionStatus> getGarbageCollectionStatus() {
return
Collections.singletonList(gcThread.getGarbageCollectionStatus());
}
+
+ @Override
+ public byte[] getEntriesOfLedger(long ledgerId) throws Exception {
+ return getEntriesOfLedger(ledgerId, Collections.emptyIterator());
+ }
+
+ public static final long INVALID_ENTRYID = -1;
+
+ /*
+ *
+ * Nomenclature:
+ *
+ * - Continuous entries are grouped as a ’Sequence’. - Number of continuous
+ * entries in a ‘Sequence’ is called ‘sequenceSize’. - Gap between
+ * Consecutive sequences is called ‘sequencePeriod’. - Consecutive
sequences
+ * with same sequenceSize and same sequencePeriod in between consecutive
+ * sequences are grouped as a SequenceGroup. - ‘firstSequenceStart’ is the
+ * first entry in the first sequence of the SequenceGroup. -
+ * ‘lastSequenceStart’ is the first entry in the last sequence of the
+ * SequenceGroup.
+ *
+ * To represent a SequenceGroup, two long values and two int values are
+ * needed, so each SequenceGroup can be represented with (2 * 8 + 2 * 4 =
24
+ * bytes).
+ */
+ private static class SequenceGroup {
+ private final long firstSequenceStart;
+ private int sequenceSize;
+ long lastSequenceStart = INVALID_ENTRYID;
+ int sequencePeriod;
+ static final int SEQUENCEGROUP_BYTES = 2 * Long.BYTES + 2 *
Integer.BYTES;
+
+ private SequenceGroup(long firstSequenceStart, int sequenceSize) {
+ this.firstSequenceStart = firstSequenceStart;
+ this.sequenceSize = sequenceSize;
+ }
+
+ void serializeSequenceGroup(byte[] byteArrayForSerialization) {
+ ByteBuffer buffer = ByteBuffer.wrap(byteArrayForSerialization);
+ buffer.putLong(firstSequenceStart);
+ buffer.putLong(lastSequenceStart);
+ buffer.putLong(sequenceSize);
+ buffer.putLong(sequencePeriod);
+ }
+ }
+
+ /*
+ * Ordered collection of SequenceGroups will represent entries of the
ledger
+ * residing in a bookie.
+ *
+ * In the byte array representation of AvailabilityOfEntriesOfLedger, for
+ * the sake of future extensibility it would be helpful to have reserved
+ * space for header at the beginning. So the first 64 bytes will be used
for
+ * header, with the first four bytes specifying the int version number,
next
+ * four bytes specifying the number of sequencegroups for now and the rest
+ * of the bytes in the reserved space will be 0's. The encoded format will
+ * be represented after the first 64 bytes. The ordered collection of
+ * SequenceGroups will be appended sequentially to this byte array, with
+ * each SequenceGroup taking 24 bytes.
+ */
+ static class AvailabilityOfEntriesOfLedger {
Review comment:
Call this something more general -- LedgerEntrySet or something.
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