SERVER-37624 Allow sessions collection TTL index expiration value to change upon node restart

(cherry picked from commit f13d685ade22d662070bde942eb094790d4e7b8d)

9 files changed, 151 insertions, 39 deletions

diff --git a/jstests/libs/sessions_collection.js b/jstests/libs/sessions_collection.js
index ba6d9b684c4..71ee9528d89 100644
--- a/jstests/libs/sessions_collection.js
+++ b/jstests/libs/sessions_collection.js
@@ -4,7 +4,8 @@
  * Validates that the sessions collection exists if we expect it to,
  * and has a TTL index on the lastUse field, if we expect it to.
  */
-function validateSessionsCollection(conn, collectionExists, indexExists, assertIfNotExists = true) {
+function validateSessionsCollection(
+    conn, collectionExists, indexExists, timeout, assertIfNotExists = true) {
     var config = conn.getDB("config");
 
     var info = config.getCollectionInfos({name: "system.sessions"});
@@ -26,6 +27,9 @@ function validateSessionsCollection(conn, collectionExists, indexExists, assertI
             assert.eq(entry["ns"], "config.system.sessions");
             assert.eq(entry["key"], {"lastUse": 1});
             assert(entry.hasOwnProperty("expireAfterSeconds"));
+            if (timeout) {
+                assert.eq(entry["expireAfterSeconds"], timeout * 60);
+            }
         }
     }
 
diff --git a/jstests/multiVersion/causal_consistency_downgrade_cluster.js b/jstests/multiVersion/causal_consistency_downgrade_cluster.js
index e45dba25306..8571b16352e 100644
--- a/jstests/multiVersion/causal_consistency_downgrade_cluster.js
+++ b/jstests/multiVersion/causal_consistency_downgrade_cluster.js
@@ -55,10 +55,10 @@
     // force config server to create sessions collection
     assert.commandWorked(
         st.configRS.getPrimary().getDB('admin').runCommand({refreshLogicalSessionCacheNow: 1}));
-    validateSessionsCollection(st.configRS.getPrimary(), false, false, true);
+    validateSessionsCollection(st.configRS.getPrimary(), false, false, null, true);
     // initially system.sessions collection has just one chunk.
-    assert(validateSessionsCollection(st.rs0.getPrimary(), true, false, false) ||
-           validateSessionsCollection(st.rs1.getPrimary(), true, false, false));
+    assert(validateSessionsCollection(st.rs0.getPrimary(), true, false, null, false) ||
+           validateSessionsCollection(st.rs1.getPrimary(), true, false, null, false));
 
     // Change featureCompatibilityVersion to 3.4.
     assert.commandWorked(st.s.adminCommand({setFeatureCompatibilityVersion: "3.4"}));
@@ -89,8 +89,8 @@
     });
 
     // Confirm that the system.sessions was dropped on the downgrade.
-    validateSessionsCollection(st.rs0.getPrimary(), false, false, true);
-    validateSessionsCollection(st.rs1.getPrimary(), false, false, true);
+    validateSessionsCollection(st.rs0.getPrimary(), false, false, null, true);
+    validateSessionsCollection(st.rs1.getPrimary(), false, false, null, true);
 
     // Downgrade mongos first.
     jsTest.log("Downgrading mongos servers.");
diff --git a/jstests/multiVersion/causal_consistency_upgrade_cluster.js b/jstests/multiVersion/causal_consistency_upgrade_cluster.js
index 39c8c812554..b3f871c1b9d 100644
--- a/jstests/multiVersion/causal_consistency_upgrade_cluster.js
+++ b/jstests/multiVersion/causal_consistency_upgrade_cluster.js
@@ -163,10 +163,10 @@
     assert.commandWorked(
         st.configRS.getPrimary().getDB('admin').runCommand({refreshLogicalSessionCacheNow: 1}));
     // system.sessions collection can never be on config server.
-    validateSessionsCollection(st.configRS.getPrimary(), false, false, true);
+    validateSessionsCollection(st.configRS.getPrimary(), false, false, null, true);
     // The system sessions collection should have been created on some shard.
-    assert(validateSessionsCollection(st.rs0.getPrimary(), true, true, false) ||
-           validateSessionsCollection(st.rs1.getPrimary(), true, true, false));
+    assert(validateSessionsCollection(st.rs0.getPrimary(), true, true, null, false) ||
+           validateSessionsCollection(st.rs1.getPrimary(), true, true, null, false));
 
     st.stop();
 })();
diff --git a/jstests/noPassthrough/sessions_collection_auto_healing.js b/jstests/noPassthrough/sessions_collection_auto_healing.js
index 21eb3d221a3..9de17041fce 100644
--- a/jstests/noPassthrough/sessions_collection_auto_healing.js
+++ b/jstests/noPassthrough/sessions_collection_auto_healing.js
@@ -7,32 +7,54 @@ load('jstests/libs/sessions_collection.js');
     // implicit sessions.
     TestData.disableImplicitSessions = true;
 
+    let timeoutMinutes = 5;
+
     var startSession = {startSession: 1};
-    var conn = MongoRunner.runMongod({nojournal: ""});
+    var conn = MongoRunner.runMongod(
+        {nojournal: "", setParameter: "localLogicalSessionTimeoutMinutes=" + timeoutMinutes});
 
     var admin = conn.getDB("admin");
     var config = conn.getDB("config");
 
     // Test that we can use sessions before the sessions collection exists.
     {
-        validateSessionsCollection(conn, false, false);
+        validateSessionsCollection(conn, false, false, timeoutMinutes);
         assert.commandWorked(admin.runCommand({startSession: 1}));
-        validateSessionsCollection(conn, false, false);
+        validateSessionsCollection(conn, false, false, timeoutMinutes);
     }
 
     // Test that a refresh will create the sessions collection.
     {
         assert.commandWorked(admin.runCommand({refreshLogicalSessionCacheNow: 1}));
-        validateSessionsCollection(conn, true, true);
+        validateSessionsCollection(conn, true, true, timeoutMinutes);
     }
 
     // Test that a refresh will (re)create the TTL index on the sessions collection.
     {
         assert.commandWorked(config.system.sessions.dropIndex({lastUse: 1}));
-        validateSessionsCollection(conn, true, false);
+        validateSessionsCollection(conn, true, false, timeoutMinutes);
+        assert.commandWorked(admin.runCommand({refreshLogicalSessionCacheNow: 1}));
+        validateSessionsCollection(conn, true, true, timeoutMinutes);
+    }
+
+    MongoRunner.stopMongod(conn);
+
+    timeoutMinutes = 4;
+    conn = MongoRunner.runMongod({
+        restart: conn,
+        cleanData: false,
+        setParameter: "localLogicalSessionTimeoutMinutes=" + timeoutMinutes
+    });
+    admin = conn.getDB("admin");
+    config = conn.getDB("config");
+
+    // Test that a change to the TTL index expiration on restart will generate a collMod to change
+    // the expiration time.
+    {
         assert.commandWorked(admin.runCommand({refreshLogicalSessionCacheNow: 1}));
-        validateSessionsCollection(conn, true, true);
+        validateSessionsCollection(conn, true, true, timeoutMinutes);
     }
 
     MongoRunner.stopMongod(conn);
+
 })();
diff --git a/jstests/replsets/sessions_collection_auto_healing.js b/jstests/replsets/sessions_collection_auto_healing.js
index ed332241921..b75ed876d25 100644
--- a/jstests/replsets/sessions_collection_auto_healing.js
+++ b/jstests/replsets/sessions_collection_auto_healing.js
@@ -21,75 +21,102 @@ load('jstests/libs/sessions_collection.js');
     var secondary = replTest.getSecondary();
     var secondaryAdmin = secondary.getDB("admin");
 
+    // Get the current value of the TTL index so that we can verify it's being properly applied.
+    let res = assert.commandWorked(
+        primary.adminCommand({getParameter: 1, localLogicalSessionTimeoutMinutes: 1}));
+    let timeoutMinutes = res.localLogicalSessionTimeoutMinutes;
+
     // Test that we can use sessions on the primary before the sessions collection exists.
     {
-        validateSessionsCollection(primary, false, false);
+        validateSessionsCollection(primary, false, false, timeoutMinutes);
 
         assert.commandWorked(primaryAdmin.runCommand({startSession: 1}));
 
-        validateSessionsCollection(primary, false, false);
+        validateSessionsCollection(primary, false, false, timeoutMinutes);
     }
 
     // Test that we can use sessions on secondaries before the sessions collection exists.
     {
-        validateSessionsCollection(primary, false, false);
+        validateSessionsCollection(primary, false, false, timeoutMinutes);
 
         replTest.awaitReplication();
-        validateSessionsCollection(secondary, false, false);
+        validateSessionsCollection(secondary, false, false, timeoutMinutes);
 
         assert.commandWorked(secondaryAdmin.runCommand({startSession: 1}));
 
-        validateSessionsCollection(primary, false, false);
+        validateSessionsCollection(primary, false, false, timeoutMinutes);
 
         replTest.awaitReplication();
-        validateSessionsCollection(secondary, false, false);
+        validateSessionsCollection(secondary, false, false, timeoutMinutes);
     }
 
     // Test that a refresh on a secondary does not create the sessions collection.
     {
-        validateSessionsCollection(primary, false, false);
+        validateSessionsCollection(primary, false, false, timeoutMinutes);
 
         replTest.awaitReplication();
-        validateSessionsCollection(secondary, false, false);
+        validateSessionsCollection(secondary, false, false, timeoutMinutes);
 
         assert.commandWorked(secondaryAdmin.runCommand({refreshLogicalSessionCacheNow: 1}));
 
-        validateSessionsCollection(primary, false, false);
+        validateSessionsCollection(primary, false, false, timeoutMinutes);
 
         replTest.awaitReplication();
-        validateSessionsCollection(secondary, false, false);
+        validateSessionsCollection(secondary, false, false, timeoutMinutes);
     }
     // Test that a refresh on the primary creates the sessions collection.
     {
-        validateSessionsCollection(primary, false, false);
+        validateSessionsCollection(primary, false, false, timeoutMinutes);
 
         replTest.awaitReplication();
-        validateSessionsCollection(secondary, false, false);
+        validateSessionsCollection(secondary, false, false, timeoutMinutes);
 
         assert.commandWorked(primaryAdmin.runCommand({refreshLogicalSessionCacheNow: 1}));
 
-        validateSessionsCollection(primary, true, true);
+        validateSessionsCollection(primary, true, true, timeoutMinutes);
     }
 
     // Test that a refresh on a secondary will not create the TTL index on the sessions collection.
     {
         assert.commandWorked(primary.getDB("config").system.sessions.dropIndex({lastUse: 1}));
 
-        validateSessionsCollection(primary, true, false);
+        validateSessionsCollection(primary, true, false, timeoutMinutes);
 
         assert.commandWorked(secondaryAdmin.runCommand({refreshLogicalSessionCacheNow: 1}));
 
-        validateSessionsCollection(primary, true, false);
+        validateSessionsCollection(primary, true, false, timeoutMinutes);
     }
 
     // Test that a refresh on the primary will create the TTL index on the sessions collection.
     {
-        validateSessionsCollection(primary, true, false);
+        validateSessionsCollection(primary, true, false, timeoutMinutes);
+
+        assert.commandWorked(primaryAdmin.runCommand({refreshLogicalSessionCacheNow: 1}));
+
+        validateSessionsCollection(primary, true, true, timeoutMinutes);
+    }
+
+    timeoutMinutes = 4;
 
+    replTest.restart(
+        0,
+        {startClean: false, setParameter: "localLogicalSessionTimeoutMinutes=" + timeoutMinutes});
+
+    primary = replTest.getPrimary();
+    primaryAdmin = primary.getDB("admin");
+    secondary = replTest.getSecondary();
+
+    // Test that a change to the TTL index expiration on restart will generate a collMod to change
+    // the expiration time.
+    {
         assert.commandWorked(primaryAdmin.runCommand({refreshLogicalSessionCacheNow: 1}));
 
-        validateSessionsCollection(primary, true, true);
+        validateSessionsCollection(primary, true, true, timeoutMinutes);
+
+        replTest.awaitReplication();
+        validateSessionsCollection(secondary, true, true, timeoutMinutes);
     }
 
     replTest.stopSet();
+
 })();
diff --git a/src/mongo/db/sessions_collection.cpp b/src/mongo/db/sessions_collection.cpp
index 05b6df1666c..e4bad86e337 100644
--- a/src/mongo/db/sessions_collection.cpp
+++ b/src/mongo/db/sessions_collection.cpp
@@ -318,4 +318,20 @@ BSONObj SessionsCollection::generateCreateIndexesCmd() {
 
     return createIndexes.toBSON();
 }
+
+BSONObj SessionsCollection::generateCollModCmd() {
+    BSONObjBuilder collModCmdBuilder;
+
+    collModCmdBuilder << "collMod" << kSessionsNamespaceString.coll();
+
+    BSONObjBuilder indexBuilder(collModCmdBuilder.subobjStart("index"));
+    indexBuilder << "name" << kSessionsTTLIndex;
+    indexBuilder << "expireAfterSeconds" << localLogicalSessionTimeoutMinutes * 60;
+
+    indexBuilder.done();
+    collModCmdBuilder.done();
+
+    return collModCmdBuilder.obj();
+}
+
 }  // namespace mongo
diff --git a/src/mongo/db/sessions_collection.h b/src/mongo/db/sessions_collection.h
index e592e9a7b5d..5cb0c595419 100644
--- a/src/mongo/db/sessions_collection.h
+++ b/src/mongo/db/sessions_collection.h
@@ -97,6 +97,11 @@ public:
      */
     static BSONObj generateCreateIndexesCmd();
 
+    /*
+     * Generates a collMod command for the sessions collection TTL index.
+     */
+    static BSONObj generateCollModCmd();
+
 protected:
     /**
      * Makes a send function for the given client.
diff --git a/src/mongo/db/sessions_collection_rs.cpp b/src/mongo/db/sessions_collection_rs.cpp
index e3c729ca61c..373f1618eaf 100644
--- a/src/mongo/db/sessions_collection_rs.cpp
+++ b/src/mongo/db/sessions_collection_rs.cpp
@@ -161,10 +161,22 @@ Status SessionsCollectionRS::setupSessionsCollection(OperationContext* opCtx) {
         kSessionsNamespaceString,
         opCtx,
         [&] {
-            // Creating the TTL index will auto-generate the collection.
+            auto existsStatus = checkSessionsCollectionExists(opCtx);
+            if (existsStatus.isOK()) {
+                return Status::OK();
+            }
+
             DBDirectClient client(opCtx);
+            BSONObj cmd;
+
+            if (existsStatus.code() == ErrorCodes::IndexOptionsConflict) {
+                cmd = generateCollModCmd();
+            } else {
+                // Creating the TTL index will auto-generate the collection.
+                cmd = generateCreateIndexesCmd();
+            }
+
             BSONObj info;
-            auto cmd = generateCreateIndexesCmd();
             if (!client.runCommand(kSessionsNamespaceString.db().toString(), cmd, info)) {
                 return getStatusFromCommandResult(info);
             }
@@ -183,15 +195,22 @@ Status SessionsCollectionRS::checkSessionsCollectionExists(OperationContext* opC
         return Status{ErrorCodes::NamespaceNotFound, "config.system.sessions does not exist"};
     }
 
-    auto indexExists = std::find_if(indexes.begin(), indexes.end(), [](const BSONObj& index) {
+    auto index = std::find_if(indexes.begin(), indexes.end(), [](const BSONObj& index) {
         return index.getField("name").String() == kSessionsTTLIndex;
     });
 
-    if (indexExists == indexes.end()) {
+    if (index == indexes.end()) {
         return Status{ErrorCodes::IndexNotFound,
                       "config.system.sessions does not have the required TTL index"};
     }
 
+    if (!index->hasField("expireAfterSeconds") ||
+        index->getField("expireAfterSeconds").Int() != (localLogicalSessionTimeoutMinutes * 60)) {
+        return Status{
+            ErrorCodes::IndexOptionsConflict,
+            "config.system.sessions currently has the incorrect timeout for the TTL index"};
+    }
+
     return Status::OK();
 }
 
diff --git a/src/mongo/db/sessions_collection_standalone.cpp b/src/mongo/db/sessions_collection_standalone.cpp
index b8a39186c60..e5ad672b485 100644
--- a/src/mongo/db/sessions_collection_standalone.cpp
+++ b/src/mongo/db/sessions_collection_standalone.cpp
@@ -55,8 +55,20 @@ Status SessionsCollectionStandalone::setupSessionsCollection(OperationContext* o
         return {ErrorCodes::MustUpgrade, "Can not create config.system.sessions collection"};
     }
 
+    auto existsStatus = checkSessionsCollectionExists(opCtx);
+    if (existsStatus.isOK()) {
+        return Status::OK();
+    }
+
     DBDirectClient client(opCtx);
-    auto cmd = generateCreateIndexesCmd();
+    BSONObj cmd;
+
+    if (existsStatus.code() == ErrorCodes::IndexOptionsConflict) {
+        cmd = generateCollModCmd();
+    } else {
+        cmd = generateCreateIndexesCmd();
+    }
+
     BSONObj info;
     if (!client.runCommand(kSessionsNamespaceString.db().toString(), cmd, info)) {
         return getStatusFromCommandResult(info);
@@ -74,15 +86,22 @@ Status SessionsCollectionStandalone::checkSessionsCollectionExists(OperationCont
         return Status{ErrorCodes::NamespaceNotFound, "config.system.sessions does not exist"};
     }
 
-    auto indexExists = std::find_if(indexes.begin(), indexes.end(), [](const BSONObj& index) {
+    auto index = std::find_if(indexes.begin(), indexes.end(), [](const BSONObj& index) {
         return index.getField("name").String() == kSessionsTTLIndex;
     });
 
-    if (indexExists == indexes.end()) {
+    if (index == indexes.end()) {
         return Status{ErrorCodes::IndexNotFound,
                       "config.system.sessions does not have the required TTL index"};
     };
 
+    if (!index->hasField("expireAfterSeconds") ||
+        index->getField("expireAfterSeconds").Int() != (localLogicalSessionTimeoutMinutes * 60)) {
+        return Status{
+            ErrorCodes::IndexOptionsConflict,
+            "config.system.sessions currently has the incorrect timeout for the TTL index"};
+    }
+
     return Status::OK();
 }