Add deprecated API for creating History Ops Snapshot from translog (#…

…2886) * Add deprecated API for creating History Ops Snapshot from translog Adds a deprecated API to create a history operations snapshot from the translog. This was superseded by always using the lucene index for peer recovery since the index saves on costly storage but this API enables plugins to selectively use the uncompressed xlog file for speed over disk savings. Note: this API will be either completely removed or refactored in the next release. Signed-off-by: Nicholas Walter Knize <[email protected]> Signed-off-by: Sai Kumar <[email protected]> * fix javadoc casing for deprecated Signed-off-by: Nicholas Walter Knize <[email protected]> Co-authored-by: Nicholas Walter Knize <[email protected]>
opensearch-project · Apr 15, 2022 · 2069aa3 · 2069aa3
1 parent 7bd7f2f
commit 2069aa3
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diff --git a/server/src/main/java/org/opensearch/index/engine/Engine.java b/server/src/main/java/org/opensearch/index/engine/Engine.java
@@ -742,6 +742,19 @@ public abstract Translog.Snapshot newChangesSnapshot(
         boolean accurateCount
     ) throws IOException;
 
+    /**
+     * Reads history operations from the translog file instead of the lucene index
+     *
+     * @deprecated reading history operations from the translog file is deprecated and will be removed in the next release
+     */
+    @Deprecated
+    public abstract Translog.Snapshot newChangesSnapshotFromTranslogFile(
+        String source,
+        long fromSeqNo,
+        long toSeqNo,
+        boolean requiredFullRange
+    ) throws IOException;
+
     /**
      * Counts the number of history operations in the given sequence number range
      * @param source       source of the request

diff --git a/server/src/main/java/org/opensearch/index/engine/InternalEngine.java b/server/src/main/java/org/opensearch/index/engine/InternalEngine.java
@@ -2821,6 +2821,20 @@ public Translog.Snapshot newChangesSnapshot(
         }
     }
 
+    /**
+     * Creates a new history snapshot from the translog file instead of the lucene index
+     *
+     * @deprecated reading history operations from the translog file is deprecated and will be removed in the next release
+     *
+     * Use {@link Engine#newChangesSnapshot(String, long, long, boolean, boolean)} instead
+     */
+    @Deprecated
+    @Override
+    public Translog.Snapshot newChangesSnapshotFromTranslogFile(String source, long fromSeqNo, long toSeqNo, boolean requiredFullRange)
+        throws IOException {
+        return getTranslog().newSnapshot(fromSeqNo, toSeqNo, requiredFullRange);
+    }
+
     public int countNumberOfHistoryOperations(String source, long fromSeqNo, long toSeqNo) throws IOException {
         ensureOpen();
         refreshIfNeeded(source, toSeqNo);

diff --git a/server/src/main/java/org/opensearch/index/engine/ReadOnlyEngine.java b/server/src/main/java/org/opensearch/index/engine/ReadOnlyEngine.java
@@ -335,6 +335,20 @@ public Translog.Snapshot newChangesSnapshot(
         return newEmptySnapshot();
     }
 
+    /**
+     * Creates a new history snapshot from the translog file instead of the lucene index
+     *
+     * @deprecated reading history operations from the translog file is deprecated and will be removed in the next release
+     *
+     * Use {@link Engine#newChangesSnapshot(String, long, long, boolean, boolean)} instead
+     */
+    @Deprecated
+    @Override
+    public Translog.Snapshot newChangesSnapshotFromTranslogFile(String source, long fromSeqNo, long toSeqNo, boolean requiredFullRange)
+        throws IOException {
+        return newEmptySnapshot();
+    }
+
     @Override
     public int countNumberOfHistoryOperations(String source, long fromSeqNo, long toSeqNo) throws IOException {
         try (Translog.Snapshot snapshot = newChangesSnapshot(source, fromSeqNo, toSeqNo, false, true)) {

diff --git a/server/src/main/java/org/opensearch/index/shard/IndexShard.java b/server/src/main/java/org/opensearch/index/shard/IndexShard.java
@@ -2233,13 +2233,25 @@ public Closeable acquireHistoryRetentionLock() {
     /**
      * Creates a new history snapshot for reading operations since
      * the provided starting seqno (inclusive) and ending seqno (inclusive)
-     * The returned snapshot can be retrieved from either Lucene index or translog files.
+     * The returned snapshot is retrieved from a Lucene index.
      */
     public Translog.Snapshot getHistoryOperations(String reason, long startingSeqNo, long endSeqNo, boolean accurateCount)
         throws IOException {
         return getEngine().newChangesSnapshot(reason, startingSeqNo, endSeqNo, true, accurateCount);
     }
 
+    /**
+     * Creates a new history snapshot from the translog file instead of the lucene index
+     *
+     * @deprecated reading history operations from the translog file is deprecated and will be removed in the next release
+     *
+     * Use {@link IndexShard#getHistoryOperations(String, long, long, boolean)} instead
+     */
+    @Deprecated
+    public Translog.Snapshot getHistoryOperationsFromTranslogFile(String reason, long startingSeqNo, long endSeqNo) throws IOException {
+        return getEngine().newChangesSnapshotFromTranslogFile(reason, startingSeqNo, endSeqNo, true);
+    }
+
     /**
      * Checks if we have a completed history of operations since the given starting seqno (inclusive).
      * This method should be called after acquiring the retention lock; See {@link #acquireHistoryRetentionLock()}

diff --git a/server/src/test/java/org/opensearch/index/engine/InternalEngineTests.java b/server/src/test/java/org/opensearch/index/engine/InternalEngineTests.java
@@ -6318,10 +6318,30 @@ public void testHistoryBasedOnSource() throws Exception {
                 }
             }
             List<Translog.Operation> luceneOps = readAllOperationsBasedOnSource(engine);
+            // todo remove in next release
+            List<Translog.Operation> translogOps = readAllOperationsBasedOnTranslog(engine);
             assertThat(luceneOps.stream().map(o -> o.seqNo()).collect(Collectors.toList()), containsInAnyOrder(expectedSeqNos.toArray()));
+            assertThat(translogOps.stream().map(o -> o.seqNo()).collect(Collectors.toList()), containsInAnyOrder(expectedSeqNos.toArray()));
         }
     }
 
+    /**
+     * Test creating new snapshot from translog file
+     *
+     * @deprecated reading history operations from the translog file is deprecated and will be removed in the next release
+     */
+    @Deprecated
+    private static List<Translog.Operation> readAllOperationsBasedOnTranslog(Engine engine) throws IOException {
+        final List<Translog.Operation> operations = new ArrayList<>();
+        try (Translog.Snapshot snapshot = engine.newChangesSnapshotFromTranslogFile("test", 0, Long.MAX_VALUE, false)) {
+            Translog.Operation op;
+            while ((op = snapshot.next()) != null) {
+                operations.add(op);
+            }
+        }
+        return operations;
+    }
+
     public void testLuceneHistoryOnPrimary() throws Exception {
         final List<Engine.Operation> operations = generateSingleDocHistory(
             false,