hanishakoneru commented on a change in pull request #1480:
URL: https://github.com/apache/ozone/pull/1480#discussion_r516997347
##########
File path:
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OzoneManager.java
##########
@@ -306,6 +306,15 @@
private final Map<String, RatisDropwizardExports> ratisMetricsMap =
new ConcurrentHashMap<>();
+ // Epoch is used to generate the objectIDs. The most significant 2 bits of
+ // objectIDs is set to this epoch. For clusters before HDDS-4315 there is
+ // no epoch as such. But it can be safely assumed that the most significant
+ // 2 bits of the objectID will be 00. From HDDS-4315 onwards, the Epoch for
+ // non-ratis OM clusters will be binary 01 (= decimal 1) and for ratis
Review comment:
It would help if we ever wanted to update the non-unique objectIds to
maintain uniqueness throughout.
##########
File path:
hadoop-ozone/common/src/main/java/org/apache/hadoop/ozone/OmUtils.java
##########
@@ -524,6 +535,48 @@ public static OmKeyInfo prepareKeyForRecover(OmKeyInfo
keyInfo,
}
}
+ public static int getOMEpoch(boolean isRatisEnabled) {
+ return isRatisEnabled ? EPOCH_WHEN_RATIS_ENABLED :
+ EPOCH_WHEN_RATIS_NOT_ENABLED;
+ }
+
+ /**
+ * Get the valid base object id given the transaction id.
+ * @param epoch a 2 bit epoch number. The 2 most significant bits of the
+ * object will be set to this epoch.
+ * @param id of the transaction. This value cannot exceed 2^54 - 1 as
+ * out of the 64 bits for a long, 2 are reserved for the epoch
+ * and 8 for recursive directory creation.
+ * @return base object id allocated against the transaction
+ */
+ public static long getObjectIdFromTxId(long epoch, long id) {
+ Preconditions.checkArgument(id <= MAX_TRXN_ID, "TransactionID " +
+ "exceeds max limit of " + MAX_TRXN_ID);
+ return addEpochToObjectId(epoch, id);
+ }
+
+ /**
+ * Note - This function should not be called directly. It is directly called
+ * only from OzoneManager#addS3GVolumeToDB() which is a one time operation
+ * when OM is started first time to add S3G volume. In call other cases,
+ * getObjectIdFromTxId() should be called to append epoch to objectID.
+ */
+ public static long addEpochToObjectId(long epoch, long id) {
+ long lsb54 = id << TRANSACTION_ID_SHIFT;
+ long msb2 = epoch << EPOCH_ID_SHIFT;
+
+ return msb2 | lsb54;
+ }
+
+ /**
+ * Given an objectId, unset the 2 most significant bits to get the
+ * corresponding transaction index.
+ */
+ @VisibleForTesting
+ public static long getTxIdFromObjectId(long objectId) {
+ return ((Long.MAX_VALUE >> 2) & objectId) >> 8;
Review comment:
Done.
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