From 6a646b413e890d12fa07be40e215d00573c29b80 Mon Sep 17 00:00:00 2001
From: Alexander Tokmakov <avtokmakov@yandex-team.ru>
Date: Fri, 4 Feb 2022 00:40:17 +0300
Subject: [PATCH] fix

---
 src/Functions/FunctionsTransactionCounters.cpp  | 14 ++++++++++++--
 src/Interpreters/TransactionVersionMetadata.cpp |  4 ++--
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/Functions/FunctionsTransactionCounters.cpp b/src/Functions/FunctionsTransactionCounters.cpp
index f553d0a8be1..f2e9d3aa84b 100644
--- a/src/Functions/FunctionsTransactionCounters.cpp
+++ b/src/Functions/FunctionsTransactionCounters.cpp
@@ -35,18 +35,28 @@ public:
 
 class FunctionTransactionLatestSnapshot : public FunctionConstantBase<FunctionTransactionLatestSnapshot, UInt64, DataTypeUInt64>
 {
+    static UInt64 getLatestSnapshot(ContextPtr context)
+    {
+        context->checkTransactionsAreAllowed(/* explicit_tcl_query */ true);
+        return TransactionLog::instance().getLatestSnapshot();
+    }
 public:
     static constexpr auto name = "transactionLatestSnapshot";
     static FunctionPtr create(ContextPtr context) { return std::make_shared<FunctionTransactionLatestSnapshot>(context); }
-    explicit FunctionTransactionLatestSnapshot(ContextPtr context) : FunctionConstantBase(TransactionLog::instance().getLatestSnapshot(), context->isDistributed()) {}
+    explicit FunctionTransactionLatestSnapshot(ContextPtr context) : FunctionConstantBase(getLatestSnapshot(context), context->isDistributed()) {}
 };
 
 class FunctionTransactionOldestSnapshot : public FunctionConstantBase<FunctionTransactionOldestSnapshot, UInt64, DataTypeUInt64>
 {
+    static UInt64 getOldestSnapshot(ContextPtr context)
+    {
+        context->checkTransactionsAreAllowed(/* explicit_tcl_query */ true);
+        return TransactionLog::instance().getOldestSnapshot();
+    }
 public:
     static constexpr auto name = "transactionOldestSnapshot";
     static FunctionPtr create(ContextPtr context) { return std::make_shared<FunctionTransactionOldestSnapshot>(context); }
-    explicit FunctionTransactionOldestSnapshot(ContextPtr context) : FunctionConstantBase(TransactionLog::instance().getOldestSnapshot(), context->isDistributed()) {}
+    explicit FunctionTransactionOldestSnapshot(ContextPtr context) : FunctionConstantBase(getOldestSnapshot(context), context->isDistributed()) {}
 };
 
 }
diff --git a/src/Interpreters/TransactionVersionMetadata.cpp b/src/Interpreters/TransactionVersionMetadata.cpp
index b22683855ce..e80d08a1944 100644
--- a/src/Interpreters/TransactionVersionMetadata.cpp
+++ b/src/Interpreters/TransactionVersionMetadata.cpp
@@ -52,10 +52,10 @@ TransactionID VersionMetadata::getRemovalTID() const
     TIDHash max_lock = removal_tid_lock.load();
     if (max_lock)
     {
-        if (auto txn = TransactionLog::instance().tryGetRunningTransaction(max_lock))
-            return txn->tid;
         if (max_lock == Tx::PrehistoricTID.getHash())
             return Tx::PrehistoricTID;
+        if (auto txn = TransactionLog::instance().tryGetRunningTransaction(max_lock))
+            return txn->tid;
     }
 
     if (removal_csn.load(std::memory_order_relaxed))