MB-51805: Pass persistedPrepareSeqno(maxPrepareSeqno) into Checkpoint

We set the value of the first Checkpoint to this value to ensure that the on disk HPS is correctly updated if we partially persist a snapshot, restart, and find on streaming the rest of the snapshot that it does not contain any prepares. Change-Id: I216effaa2d0f12e0c7d4bb0d67d7e2510526e2fa Reviewed-on: https://review.couchbase.org/c/kv_engine/+/173917 Well-Formed: Restriction Checker Tested-by: Build Bot <build@couchbase.com> Reviewed-by: Paolo Cocchi <paolo.cocchi@couchbase.com>
couchbase · May 13, 2022 · 027f65f · 027f65f
1 parent ef87bb3
commit 027f65f
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Showing 4 changed files with 11 additions and 1 deletion.
diff --git a/engines/ep/src/checkpoint.cc b/engines/ep/src/checkpoint.cc
@@ -55,6 +55,7 @@ Checkpoint::Checkpoint(CheckpointManager& manager,
                        uint64_t snapEnd,
                        uint64_t visibleSnapEnd,
                        std::optional<uint64_t> highCompletedSeqno,
+                       uint64_t highPreparedSeqno,
                        Vbid vbid,
                        CheckpointType checkpointType)
     : manager(&manager),
@@ -79,6 +80,7 @@ Checkpoint::Checkpoint(CheckpointManager& manager,
     auto& core = stats.coreLocal.get();
     core->memOverhead.fetch_add(sizeof(Checkpoint));
     core->numCheckpoints++;
+    this->highPreparedSeqno.reset(highPreparedSeqno);
 
     // the overheadChangedCallback uses the accurately tracked overhead
     // from queueAllocator. The above memOverhead stat is "manually"

diff --git a/engines/ep/src/checkpoint.h b/engines/ep/src/checkpoint.h
@@ -282,6 +282,7 @@ class Checkpoint {
                uint64_t snapEnd,
                uint64_t visibleSnapEnd,
                std::optional<uint64_t> highCompletedSeqno,
+               uint64_t highPreparedSeqno,
                Vbid vbid,
                CheckpointType checkpointType);
 

diff --git a/engines/ep/src/checkpoint_manager.cc b/engines/ep/src/checkpoint_manager.cc
@@ -63,6 +63,7 @@ CheckpointManager::CheckpointManager(EPStats& st,
                       lastSnapEnd,
                       maxVisibleSeqno,
                       {},
+                      maxPrepareSeqno,
                       CheckpointType::Memory);
 
     if (checkpointConfig.isPersistenceEnabled()) {
@@ -160,6 +161,7 @@ void CheckpointManager::addNewCheckpoint(
                       snapEndSeqno,
                       visibleSnapEnd,
                       highCompletedSeqno,
+                      0, // HPS - default to 0 for now
                       checkpointType);
 
     // If cursors reached to the end of its current checkpoint, move it to the
@@ -205,6 +207,7 @@ void CheckpointManager::addOpenCheckpoint(
         uint64_t snapEnd,
         uint64_t visibleSnapEnd,
         std::optional<uint64_t> highCompletedSeqno,
+        uint64_t highPreparedSeqno,
         CheckpointType checkpointType) {
     Expects(checkpointList.empty() ||
             checkpointList.back()->getState() ==
@@ -216,13 +219,14 @@ void CheckpointManager::addOpenCheckpoint(
     EP_LOG_DEBUG(
             "CheckpointManager::addOpenCheckpoint: Create "
             "a new open checkpoint: [{}, id:{}, snapStart:{}, snapEnd:{}, "
-            "visibleSnapEnd:{}, hcs:{}, type:{}]",
+            "visibleSnapEnd:{}, hcs:{}, hps:{} type:{}]",
             vb.getId(),
             id,
             snapStart,
             snapEnd,
             visibleSnapEnd,
             to_string_or_none(highCompletedSeqno),
+            highPreparedSeqno,
             to_string(checkpointType));
 
     auto ckpt = std::make_unique<Checkpoint>(*this,
@@ -232,6 +236,7 @@ void CheckpointManager::addOpenCheckpoint(
                                              snapEnd,
                                              visibleSnapEnd,
                                              highCompletedSeqno,
+                                             highPreparedSeqno,
                                              vb.getId(),
                                              checkpointType);
     // Add an empty-item into the new checkpoint.
@@ -1140,6 +1145,7 @@ void CheckpointManager::clear(const std::lock_guard<std::mutex>& lh,
                       lastBySeqno + 1,
                       maxVisibleSeqno,
                       {},
+                      0, // HPS=0 because we have correct val on disk and in PDM
                       CheckpointType::Memory);
     resetCursors();
 }

diff --git a/engines/ep/src/checkpoint_manager.h b/engines/ep/src/checkpoint_manager.h
@@ -792,6 +792,7 @@ class CheckpointManager {
                            uint64_t snapEnd,
                            uint64_t visibleSnapEnd,
                            std::optional<uint64_t> highCompletedSeqno,
+                           uint64_t highPreparedSeqno,
                            CheckpointType checkpointType);
 
     /**