From 5d7e40af99caa8eaceb466608bd0bcbfd19cae49 Mon Sep 17 00:00:00 2001
From: Tomasz Grabiec <tgrabiec@scylladb.com>
Date: Fri, 14 Oct 2022 17:55:49 +0200
Subject: [PATCH] mvcc: Add snapshot details to the printout of partition_entry

Useful for debugging.

Closes #11788
---
 partition_version.cc | 14 ++++++++++++--
 partition_version.hh |  4 +++-
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/partition_version.cc b/partition_version.cc
index d5eef6e8b3..30c01f14fe 100644
--- a/partition_version.cc
+++ b/partition_version.cc
@@ -665,9 +665,19 @@ std::ostream& operator<<(std::ostream& out, const partition_entry::printer& p) {
                 out << ", ";
             }
             if (v->is_referenced()) {
-                out << "(*) ";
+                partition_snapshot* snp = nullptr;
+                if (first) {
+                    snp = e._snapshot;
+                } else {
+                    snp = &partition_snapshot::container_of(&v->back_reference());
+                }
+                out << "(*";
+                if (snp) {
+                    out << " snp=" << snp << ", phase=" << snp->phase();
+                }
+                out << ") ";
             }
-            out << mutation_partition::printer(p._schema, v->partition());
+            out << fmt::ptr(v) << ": " << mutation_partition::printer(p._schema, v->partition());
             v = v->next();
             first = false;
         }
diff --git a/partition_version.hh b/partition_version.hh
index c60727f321..ba0247b560 100644
--- a/partition_version.hh
+++ b/partition_version.hh
@@ -163,7 +163,7 @@ public:
     bool is_referenced() const { return _backref; }
     // Returns true iff this version is directly referenced from a partition_entry (is its newset version).
     bool is_referenced_from_entry() const;
-    partition_version_ref& back_reference() { return *_backref; }
+    partition_version_ref& back_reference() const { return *_backref; }
 
     size_t size_in_allocator(const schema& s, allocation_strategy& allocator) const;
 };
@@ -412,6 +412,8 @@ public:
                                     bool reversed = false);
     // Returns all range tombstones
     range_tombstone_result range_tombstones();
+
+    phase_type phase() const { return _phase; }
 };
 
 class partition_snapshot_ptr {