SERVER-47997: Remove cachePressureThreshold and isCacheUnderPressuref1b99df5

24 files changed, 30 insertions, 277 deletions

diff --git a/jstests/noPassthrough/snapshot_history_window.js b/jstests/noPassthrough/snapshot_history_window.js
index 02e50fd622b..391af8b8372 100644
--- a/jstests/noPassthrough/snapshot_history_window.js
+++ b/jstests/noPassthrough/snapshot_history_window.js
@@ -60,5 +60,11 @@ assert.commandFailedWithCode(
         {find: collName, readConcern: {level: "snapshot", atClusterTime: insertTimestamp}}),
     ErrorCodes.SnapshotTooOld);
 
+// Test that the SnapshotTooOld is recorded in serverStatus.
+const serverStatusWT = assert.commandWorked(primaryDB.adminCommand({serverStatus: 1})).wiredTiger;
+assert.eq(1,
+          serverStatusWT["snapshot-window-settings"]["total number of SnapshotTooOld errors"],
+          tojson(serverStatusWT));
+
 replSet.stopSet();
 })();
diff --git a/src/mongo/db/SConscript b/src/mongo/db/SConscript
index 9519d1207f1..cbe71aab431 100644
--- a/src/mongo/db/SConscript
+++ b/src/mongo/db/SConscript
@@ -816,7 +816,6 @@ env.Library(
         'introspect',
         'lasterror',
         'query_exec',
-        'snapshot_window_options',
         'transaction',
         '$BUILD_DIR/mongo/db/audit',
         '$BUILD_DIR/mongo/db/auth/auth',
@@ -1467,7 +1466,6 @@ env.Library(
 env.Library(
     target='snapshot_window_options',
     source=[
-        'snapshot_window_options.cpp',
         env.Idlc('snapshot_window_options.idl')[0],
     ],
     LIBDEPS_PRIVATE=[
diff --git a/src/mongo/db/service_entry_point_common.cpp b/src/mongo/db/service_entry_point_common.cpp
index 0a3072214e9..9f0349a2f20 100644
--- a/src/mongo/db/service_entry_point_common.cpp
+++ b/src/mongo/db/service_entry_point_common.cpp
@@ -76,7 +76,6 @@
 #include "mongo/db/s/transaction_coordinator_factory.h"
 #include "mongo/db/service_entry_point_common.h"
 #include "mongo/db/session_catalog_mongod.h"
-#include "mongo/db/snapshot_window_options.h"
 #include "mongo/db/stats/counters.h"
 #include "mongo/db/stats/server_read_concern_metrics.h"
 #include "mongo/db/stats/top.h"
@@ -1228,20 +1227,7 @@ void execCommandDatabase(OperationContext* opCtx,
             throw;
         }
     } catch (const DBException& e) {
-        if (e.code() == ErrorCodes::SnapshotTooOld) {
-            // SnapshotTooOld errors should never be thrown unless we are using a storage engine
-            // that supports snapshot read concern.
-            auto engine = opCtx->getServiceContext()->getStorageEngine();
-            invariant(engine && engine->supportsReadConcernSnapshot());
-
-            // SnapshotTooOld errors indicate that PIT ops are failing to find an available
-            // snapshot at their specified atClusterTime. Therefore, we'll try to increase the
-            // snapshot history window that the storage engine maintains in order to increase
-            // the likelihood of successful future PIT atClusterTime requests.
-            snapshotWindowParams.snapshotTooOldErrorCount.addAndFetch(1);
-        } else {
-            behaviors.handleException(e, opCtx);
-        }
+        behaviors.handleException(e, opCtx);
 
         // Append the error labels for transient transaction errors.
         auto response = extraFieldsBuilder.asTempObj();
diff --git a/src/mongo/db/snapshot_window_options.cpp b/src/mongo/db/snapshot_window_options.cpp
deleted file mode 100644
index 04814862e2c..00000000000
--- a/src/mongo/db/snapshot_window_options.cpp
+++ /dev/null
@@ -1,38 +0,0 @@
-/**
- *    Copyright (C) 2018-present MongoDB, Inc.
- *
- *    This program is free software: you can redistribute it and/or modify
- *    it under the terms of the Server Side Public License, version 1,
- *    as published by MongoDB, Inc.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    Server Side Public License for more details.
- *
- *    You should have received a copy of the Server Side Public License
- *    along with this program. If not, see
- *    <http://www.mongodb.com/licensing/server-side-public-license>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the Server Side Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/db/snapshot_window_options.h"
-
-namespace mongo {
-
-SnapshotWindowParams snapshotWindowParams;
-
-}  // namespace mongo
diff --git a/src/mongo/db/snapshot_window_options.h b/src/mongo/db/snapshot_window_options.h
deleted file mode 100644
index dafeee5b28e..00000000000
--- a/src/mongo/db/snapshot_window_options.h
+++ /dev/null
@@ -1,64 +0,0 @@
-/**
- *    Copyright (C) 2018-present MongoDB, Inc.
- *
- *    This program is free software: you can redistribute it and/or modify
- *    it under the terms of the Server Side Public License, version 1,
- *    as published by MongoDB, Inc.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    Server Side Public License for more details.
- *
- *    You should have received a copy of the Server Side Public License
- *    along with this program. If not, see
- *    <http://www.mongodb.com/licensing/server-side-public-license>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the Server Side Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include "mongo/idl/mutable_observer_registry.h"
-#include "mongo/platform/atomic_proxy.h"
-#include "mongo/platform/atomic_word.h"
-
-namespace mongo {
-
-/**
- * These are parameters that affect how much snapshot history the storage engine will keep to
- * support snapshot reads. This is referred to as the snapshot window. The window is between the
- * stable timestamp and the oldest timestamp.
- */
-struct SnapshotWindowParams {
-
-    // minSnapshotHistoryWindowInSeconds (startup & runtime server parameter, range 0+).
-    //
-    // Dictates the lag in seconds oldest_timestamp should be set behind stable_timestamp.
-    //
-    // Note that the window size can become greater than this if an ongoing operation is holding an
-    // older snapshot open.
-    AtomicWord<int> minSnapshotHistoryWindowInSeconds{5};
-
-    // cachePressureThreshold (startup & runtime server parameter, range [0, 100]).
-    //
-    // Compares against a storage engine cache pressure indicator that ranges from 0 to 100.
-    // Currently, the only indicator is the WT lookaside score.
-    AtomicWord<int> cachePressureThreshold{95};
-
-    AtomicWord<std::int64_t> snapshotTooOldErrorCount{0};
-};
-
-extern SnapshotWindowParams snapshotWindowParams;
-
-}  // namespace mongo
diff --git a/src/mongo/db/snapshot_window_options.idl b/src/mongo/db/snapshot_window_options.idl
index 97af09647a2..a5eae77268c 100644
--- a/src/mongo/db/snapshot_window_options.idl
+++ b/src/mongo/db/snapshot_window_options.idl
@@ -28,8 +28,6 @@
 
 global:
   cpp_namespace: "mongo"
-  cpp_includes:
-    - "mongo/db/snapshot_window_options.h"
 
 imports:
   - "mongo/idl/basic_types.idl"
@@ -38,13 +36,7 @@ server_parameters:
   minSnapshotHistoryWindowInSeconds:
     description: "Minimum snapshot history to keep, in seconds"
     set_at: [ startup, runtime ]
-    cpp_varname: "snapshotWindowParams.minSnapshotHistoryWindowInSeconds"
+    cpp_vartype: AtomicWord<int>
+    cpp_varname: minSnapshotHistoryWindowInSeconds
+    default: 5
     validator: { gte: 0 }
-
-  cachePressureThreshold:
-    description: "Cache pressure threshold"
-    set_at: [ startup, runtime ]
-    cpp_varname: "snapshotWindowParams.cachePressureThreshold"
-    validator:
-      gte: 0
-      lte: 100
diff --git a/src/mongo/db/storage/biggie/SConscript b/src/mongo/db/storage/biggie/SConscript
index 11706d48971..f96f7e7c249 100644
--- a/src/mongo/db/storage/biggie/SConscript
+++ b/src/mongo/db/storage/biggie/SConscript
@@ -22,7 +22,6 @@ env.Library(
     ],
     LIBDEPS_PRIVATE=[
         '$BUILD_DIR/mongo/db/storage/key_string',
-        '$BUILD_DIR/mongo/db/snapshot_window_options',
         '$BUILD_DIR/mongo/db/storage/oplog_hack',
         '$BUILD_DIR/mongo/db/storage/write_unit_of_work',
     ],
diff --git a/src/mongo/db/storage/biggie/biggie_kv_engine.cpp b/src/mongo/db/storage/biggie/biggie_kv_engine.cpp
index 3e77b6a8cf3..7c83398126b 100644
--- a/src/mongo/db/storage/biggie/biggie_kv_engine.cpp
+++ b/src/mongo/db/storage/biggie/biggie_kv_engine.cpp
@@ -36,7 +36,6 @@
 #include <memory>
 
 #include "mongo/db/index/index_descriptor.h"
-#include "mongo/db/snapshot_window_options.h"
 #include "mongo/db/storage/biggie/biggie_recovery_unit.h"
 #include "mongo/db/storage/key_string.h"
 #include "mongo/db/storage/record_store.h"
@@ -49,10 +48,6 @@ mongo::RecoveryUnit* KVEngine::newRecoveryUnit() {
     return new RecoveryUnit(this, nullptr);
 }
 
-void KVEngine::setCachePressureForTest(int pressure) {
-    // TODO : implement.
-}
-
 Status KVEngine::createRecordStore(OperationContext* opCtx,
                                    StringData ns,
                                    StringData ident,
diff --git a/src/mongo/db/storage/biggie/biggie_kv_engine.h b/src/mongo/db/storage/biggie/biggie_kv_engine.h
index 2ce35d07cbf..63e89e8b579 100644
--- a/src/mongo/db/storage/biggie/biggie_kv_engine.h
+++ b/src/mongo/db/storage/biggie/biggie_kv_engine.h
@@ -105,12 +105,6 @@ public:
         return true;
     }
 
-    virtual bool isCacheUnderPressure(OperationContext* opCtx) const override {
-        return false;
-    }
-
-    virtual void setCachePressureForTest(int pressure) override;
-
     virtual int64_t getIdentSize(OperationContext* opCtx, StringData ident) {
         return 0;
     }
diff --git a/src/mongo/db/storage/devnull/SConscript b/src/mongo/db/storage/devnull/SConscript
index 66dcb6763a7..f2963e59380 100644
--- a/src/mongo/db/storage/devnull/SConscript
+++ b/src/mongo/db/storage/devnull/SConscript
@@ -13,9 +13,6 @@ env.Library(
         '$BUILD_DIR/mongo/db/storage/ephemeral_for_test/ephemeral_for_test_record_store',
         '$BUILD_DIR/mongo/db/storage/kv/kv_prefix',
     ],
-    LIBDEPS_PRIVATE=[
-        '$BUILD_DIR/mongo/db/snapshot_window_options',
-    ],
 )
 
 env.Library(
diff --git a/src/mongo/db/storage/devnull/devnull_kv_engine.cpp b/src/mongo/db/storage/devnull/devnull_kv_engine.cpp
index 4bbc0b9dc11..f70b7ad94fd 100644
--- a/src/mongo/db/storage/devnull/devnull_kv_engine.cpp
+++ b/src/mongo/db/storage/devnull/devnull_kv_engine.cpp
@@ -33,7 +33,6 @@
 
 #include <memory>
 
-#include "mongo/db/snapshot_window_options.h"
 #include "mongo/db/storage/ephemeral_for_test/ephemeral_for_test_record_store.h"
 #include "mongo/db/storage/record_store.h"
 #include "mongo/db/storage/sorted_data_interface.h"
@@ -244,15 +243,6 @@ std::unique_ptr<SortedDataInterface> DevNullKVEngine::getSortedDataInterface(
     return std::make_unique<DevNullSortedDataInterface>();
 }
 
-bool DevNullKVEngine::isCacheUnderPressure(OperationContext* opCtx) const {
-    return (_cachePressureForTest >= snapshotWindowParams.cachePressureThreshold.load());
-}
-
-void DevNullKVEngine::setCachePressureForTest(int pressure) {
-    invariant(pressure >= 0 && pressure <= 100);
-    _cachePressureForTest = pressure;
-}
-
 namespace {
 
 class StreamingCursorImpl : public StorageEngine::StreamingCursor {
diff --git a/src/mongo/db/storage/devnull/devnull_kv_engine.h b/src/mongo/db/storage/devnull/devnull_kv_engine.h
index f271ae0f0f8..dd1854e0256 100644
--- a/src/mongo/db/storage/devnull/devnull_kv_engine.h
+++ b/src/mongo/db/storage/devnull/devnull_kv_engine.h
@@ -97,10 +97,6 @@ public:
         return true;
     }
 
-    virtual bool isCacheUnderPressure(OperationContext* opCtx) const override;
-
-    virtual void setCachePressureForTest(int pressure) override;
-
     virtual int64_t getIdentSize(OperationContext* opCtx, StringData ident) {
         return 1;
     }
diff --git a/src/mongo/db/storage/kv/kv_engine.h b/src/mongo/db/storage/kv/kv_engine.h
index f20897f8be2..f5ceccc0b53 100644
--- a/src/mongo/db/storage/kv/kv_engine.h
+++ b/src/mongo/db/storage/kv/kv_engine.h
@@ -356,18 +356,6 @@ public:
     virtual void setOldestTimestamp(Timestamp newOldestTimestamp, bool force) {}
 
     /**
-     * See `StorageEngine::isCacheUnderPressure()`
-     */
-    virtual bool isCacheUnderPressure(OperationContext* opCtx) const {
-        return false;
-    }
-
-    /**
-     * See 'StorageEngine::setCachePressureForTest()'
-     */
-    virtual void setCachePressureForTest(int pressure) {}
-
-    /**
      * See `StorageEngine::supportsRecoverToStableTimestamp`
      */
     virtual bool supportsRecoverToStableTimestamp() const {
diff --git a/src/mongo/db/storage/storage_engine.h b/src/mongo/db/storage/storage_engine.h
index 98285ff0f30..8d7df601b5a 100644
--- a/src/mongo/db/storage/storage_engine.h
+++ b/src/mongo/db/storage/storage_engine.h
@@ -517,21 +517,6 @@ public:
     virtual void setOldestActiveTransactionTimestampCallback(
         OldestActiveTransactionTimestampCallback callback) = 0;
 
-    /**
-     * Indicates whether the storage engine cache is under pressure.
-     *
-     * Retrieves a cache pressure value in the range [0, 100] from the storage engine, and compares
-     * it against storageGlobalParams.cachePressureThreshold, a dynamic server parameter, to
-     * determine whether cache pressure is too high.
-     */
-    virtual bool isCacheUnderPressure(OperationContext* opCtx) const = 0;
-
-    /**
-     * For unit tests only. Sets the cache pressure value with which isCacheUnderPressure()
-     * evalutates to 'pressure'.
-     */
-    virtual void setCachePressureForTest(int pressure) = 0;
-
     struct IndexIdentifier {
         const RecordId catalogId;
         const NamespaceString nss;
diff --git a/src/mongo/db/storage/storage_engine_impl.cpp b/src/mongo/db/storage/storage_engine_impl.cpp
index 91ac87542c6..d45ccf93c22 100644
--- a/src/mongo/db/storage/storage_engine_impl.cpp
+++ b/src/mongo/db/storage/storage_engine_impl.cpp
@@ -783,14 +783,6 @@ void StorageEngineImpl::setOldestActiveTransactionTimestampCallback(
     _engine->setOldestActiveTransactionTimestampCallback(callback);
 }
 
-bool StorageEngineImpl::isCacheUnderPressure(OperationContext* opCtx) const {
-    return _engine->isCacheUnderPressure(opCtx);
-}
-
-void StorageEngineImpl::setCachePressureForTest(int pressure) {
-    return _engine->setCachePressureForTest(pressure);
-}
-
 bool StorageEngineImpl::supportsRecoverToStableTimestamp() const {
     return _engine->supportsRecoverToStableTimestamp();
 }
diff --git a/src/mongo/db/storage/storage_engine_impl.h b/src/mongo/db/storage/storage_engine_impl.h
index 3fd3bab86d1..70bc31830c3 100644
--- a/src/mongo/db/storage/storage_engine_impl.h
+++ b/src/mongo/db/storage/storage_engine_impl.h
@@ -133,10 +133,6 @@ public:
     virtual void setOldestActiveTransactionTimestampCallback(
         StorageEngine::OldestActiveTransactionTimestampCallback) override;
 
-    virtual bool isCacheUnderPressure(OperationContext* opCtx) const override;
-
-    virtual void setCachePressureForTest(int pressure) override;
-
     virtual bool supportsRecoverToStableTimestamp() const override;
 
     virtual bool supportsRecoveryTimestamp() const override;
diff --git a/src/mongo/db/storage/storage_engine_mock.h b/src/mongo/db/storage/storage_engine_mock.h
index b8cb1cbde02..a4dfe3c677f 100644
--- a/src/mongo/db/storage/storage_engine_mock.h
+++ b/src/mongo/db/storage/storage_engine_mock.h
@@ -138,10 +138,7 @@ public:
     void setOldestTimestamp(Timestamp timestamp) final {}
     void setOldestActiveTransactionTimestampCallback(
         OldestActiveTransactionTimestampCallback callback) final {}
-    bool isCacheUnderPressure(OperationContext* opCtx) const final {
-        return false;
-    }
-    void setCachePressureForTest(int pressure) final {}
+
     StatusWith<StorageEngine::ReconcileResult> reconcileCatalogAndIdents(
         OperationContext* opCtx) final {
         return ReconcileResult{};
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp
index 352699a9de8..b9749e79eab 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp
@@ -69,7 +69,7 @@
 #include "mongo/db/server_options.h"
 #include "mongo/db/server_recovery.h"
 #include "mongo/db/service_context.h"
-#include "mongo/db/snapshot_window_options.h"
+#include "mongo/db/snapshot_window_options_gen.h"
 #include "mongo/db/storage/journal_listener.h"
 #include "mongo/db/storage/storage_file_util.h"
 #include "mongo/db/storage/storage_options.h"
@@ -681,7 +681,7 @@ WiredTigerKVEngine::WiredTigerKVEngine(const std::string& canonicalName,
         // We do not maintain any snapshot history for the ephemeral storage engine in production
         // because replication and sharded transactions do not currently run on the inMemory engine.
         // It is live in testing, however.
-        snapshotWindowParams.minSnapshotHistoryWindowInSeconds.store(0);
+        minSnapshotHistoryWindowInSeconds.store(0);
     }
 
     _sizeStorerUri = _uri("sizeStorer");
@@ -2017,20 +2017,20 @@ Timestamp WiredTigerKVEngine::_calculateHistoryLagFromStableTimestamp(Timestamp
 
     if (_ephemeral && !getTestCommandsEnabled()) {
         // No history should be maintained for the inMemory engine because it is not used yet.
-        invariant(snapshotWindowParams.minSnapshotHistoryWindowInSeconds.load() == 0);
+        invariant(minSnapshotHistoryWindowInSeconds.load() == 0);
     }
 
     if (stableTimestamp.getSecs() <
-        static_cast<unsigned>(snapshotWindowParams.minSnapshotHistoryWindowInSeconds.load())) {
+        static_cast<unsigned>(minSnapshotHistoryWindowInSeconds.load())) {
         // The history window is larger than the timestamp history thus far. We must wait for
         // the history to reach the window size before moving oldest_timestamp forward. This should
         // only happen in unit tests.
         return Timestamp();
     }
 
-    Timestamp calculatedOldestTimestamp(
-        stableTimestamp.getSecs() - snapshotWindowParams.minSnapshotHistoryWindowInSeconds.load(),
-        stableTimestamp.getInc());
+    Timestamp calculatedOldestTimestamp(stableTimestamp.getSecs() -
+                                            minSnapshotHistoryWindowInSeconds.load(),
+                                        stableTimestamp.getInc());
 
     if (calculatedOldestTimestamp.asULL() <= _oldestTimestamp.load()) {
         // The stable_timestamp is not far enough ahead of the oldest_timestamp for the
@@ -2285,16 +2285,6 @@ void WiredTigerKVEngine::haltOplogManager() {
     }
 }
 
-bool WiredTigerKVEngine::isCacheUnderPressure(OperationContext* opCtx) const {
-    WiredTigerSession* session = WiredTigerRecoveryUnit::get(opCtx)->getSessionNoTxn();
-    invariant(session);
-
-    int64_t score = uassertStatusOK(WiredTigerUtil::getStatisticsValue(
-        session->getSession(), "statistics:", "", WT_STAT_CONN_CACHE_LOOKASIDE_SCORE));
-
-    return (score >= snapshotWindowParams.cachePressureThreshold.load());
-}
-
 Timestamp WiredTigerKVEngine::getStableTimestamp() const {
     return Timestamp(_stableTimestamp.load());
 }
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.h b/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.h
index 4bebe95e99b..61b0589b617 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.h
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.h
@@ -273,8 +273,6 @@ public:
 
     bool supportsOplogStones() const final override;
 
-    bool isCacheUnderPressure(OperationContext* opCtx) const override;
-
     bool supportsReadConcernMajority() const final;
 
     // wiredtiger specific
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.cpp
index f9d9751d464..8d6e087a86f 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.cpp
@@ -58,6 +58,8 @@ MONGO_FAIL_POINT_DEFINE(doUntimestampedWritesForIdempotencyTests);
 
 }  // namespace
 
+AtomicWord<std::int64_t> snapshotTooOldErrorCount{0};
+
 using Section = WiredTigerOperationStats::Section;
 
 std::map<int, std::pair<StringData, Section>> WiredTigerOperationStats::_statNameMap = {
@@ -531,6 +533,9 @@ void WiredTigerRecoveryUnit::_txnOpen() {
             auto status = txnOpen.setReadSnapshot(_readAtTimestamp);
 
             if (!status.isOK() && status.code() == ErrorCodes::BadValue) {
+                // SnapshotTooOld errors indicate that PIT ops are failing to find an available
+                // snapshot at their specified atClusterTime.
+                snapshotTooOldErrorCount.addAndFetch(1);
                 uasserted(ErrorCodes::SnapshotTooOld,
                           str::stream() << "Read timestamp " << _readAtTimestamp.toString()
                                         << " is older than the oldest available timestamp.");
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.h b/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.h
index 373794582a2..d2e599181de 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.h
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.h
@@ -51,6 +51,8 @@ namespace mongo {
 using RoundUpPreparedTimestamps = WiredTigerBeginTxnBlock::RoundUpPreparedTimestamps;
 using RoundUpReadTimestamp = WiredTigerBeginTxnBlock::RoundUpReadTimestamp;
 
+extern AtomicWord<std::int64_t> snapshotTooOldErrorCount;
+
 class BSONObjBuilder;
 
 class WiredTigerOperationStats final : public StorageStats {
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit_test.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit_test.cpp
index 1f440d319b7..b50d4b79889 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit_test.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit_test.cpp
@@ -263,48 +263,6 @@ TEST_F(WiredTigerRecoveryUnitTestFixture, NoOverlapReadSource) {
     ASSERT_TRUE(rs->findRecord(opCtx1, rid3, &unused));
 }
 
-TEST_F(WiredTigerRecoveryUnitTestFixture, CreateAndCheckForCachePressure) {
-    int time = 1;
-
-    // Reconfigure the size of the cache to be very small so that building cache pressure is fast.
-    WiredTigerKVEngine* engine = harnessHelper->getEngine();
-    std::string cacheSizeReconfig = "cache_size=1MB";
-    ASSERT_EQ(engine->reconfigure(cacheSizeReconfig.c_str()), 0);
-
-    OperationContext* opCtx = clientAndCtx1.second.get();
-    std::unique_ptr<RecordStore> rs(harnessHelper->createRecordStore(opCtx, "a.b"));
-
-    // Insert one document so that we can then update it in a loop to create cache pressure.
-    // Note: inserts will not create cache pressure.
-    WriteUnitOfWork wu(opCtx);
-    ASSERT_OK(ru1->setTimestamp(Timestamp(time++)));
-    std::string str = str::stream() << "foobarbaz";
-    StatusWith<RecordId> ress = rs->insertRecord(opCtx, str.c_str(), str.size() + 1, Timestamp());
-    ASSERT_OK(ress.getStatus());
-    auto recordId = ress.getValue();
-    wu.commit();
-
-    for (int j = 0; j < 1000; ++j) {
-        // Once we hit the cache pressure threshold, i.e. have successfully created cache pressure
-        // that is detectable, we are done.
-        if (engine->isCacheUnderPressure(opCtx)) {
-            invariant(j != 0);
-            break;
-        }
-
-        try {
-            WriteUnitOfWork wuow(opCtx);
-            ASSERT_OK(ru1->setTimestamp(Timestamp(time++)));
-            std::string s = str::stream()
-                << "abcbcdcdedefefgfghghihijijkjklklmlmnmnomopopqpqrqrsrststutuv" << j;
-            ASSERT_OK(rs->updateRecord(opCtx, recordId, s.c_str(), s.size() + 1));
-            wuow.commit();
-        } catch (const DBException& ex) {
-            invariant(ex.toStatus().code() == ErrorCodes::WriteConflict);
-        }
-    }
-}
-
 TEST_F(WiredTigerRecoveryUnitTestFixture,
        LocalReadOnADocumentBeingPreparedWithoutIgnoringPreparedTriggersPrepareConflict) {
     // Prepare but don't commit a transaction
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_util.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_util.cpp
index d2187782a2b..2b8f2d667fe 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_util.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_util.cpp
@@ -38,7 +38,7 @@
 #include "mongo/base/simple_string_data_comparator.h"
 #include "mongo/bson/bsonobjbuilder.h"
 #include "mongo/db/concurrency/write_conflict_exception.h"
-#include "mongo/db/snapshot_window_options.h"
+#include "mongo/db/snapshot_window_options_gen.h"
 #include "mongo/db/storage/wiredtiger/wiredtiger_kv_engine.h"
 #include "mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.h"
 #include "mongo/db/storage/wiredtiger/wiredtiger_session_cache.h"
@@ -738,18 +738,12 @@ void WiredTigerUtil::appendSnapshotWindowSettings(WiredTigerKVEngine* engine,
     const unsigned currentAvailableSnapshotWindow =
         stableTimestamp.getSecs() - oldestTimestamp.getSecs();
 
-    int64_t score = uassertStatusOK(WiredTigerUtil::getStatisticsValue(
-        session->getSession(), "statistics:", "", WT_STAT_CONN_CACHE_LOOKASIDE_SCORE));
-
-    auto totalNumberOfSnapshotTooOldErrors = snapshotWindowParams.snapshotTooOldErrorCount.load();
+    auto totalNumberOfSnapshotTooOldErrors = snapshotTooOldErrorCount.load();
 
     BSONObjBuilder settings(bob->subobjStart("snapshot-window-settings"));
-    settings.append("cache pressure percentage threshold",
-                    snapshotWindowParams.cachePressureThreshold.load());
-    settings.append("current cache pressure percentage", score);
     settings.append("total number of SnapshotTooOld errors", totalNumberOfSnapshotTooOldErrors);
     settings.append("minimum target snapshot window size in seconds",
-                    snapshotWindowParams.minSnapshotHistoryWindowInSeconds.load());
+                    minSnapshotHistoryWindowInSeconds.load());
     settings.append("current available snapshot window size in seconds",
                     static_cast<int>(currentAvailableSnapshotWindow));
     settings.append("latest majority snapshot timestamp available",
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_util.h b/src/mongo/db/storage/wiredtiger/wiredtiger_util.h
index 72ccee41b4f..e1e1a190b28 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_util.h
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_util.h
@@ -158,12 +158,9 @@ public:
      * that affect that window of maintained history.
      *
      * "snapshot-window-settings" : {
-     *      "cache pressure percentage threshold" : <num>,
-     *      "current cache pressure percentage" : <num>,
      *      "total number of SnapshotTooOld errors" : <num>,
-     *      "max target available snapshots window size in seconds" : <num>,
-     *      "target available snapshots window size in seconds" : <num>,
-     *      "current available snapshots window size in seconds" : <num>,
+     *      "minimum target snapshot window size in seconds" : <num>,
+     *      "current available snapshot window size in seconds" : <num>,
      *      "latest majority snapshot timestamp available" : <num>,
      *      "oldest majority snapshot timestamp available" : <num>
      * }