1 files changed, 66 insertions, 2 deletions
diff --git a/src/mongo/db/query/query_knobs.idl b/src/mongo/db/query/query_knobs.idl
index 0748cee3a33..f0f24d3c3dd 100644
--- a/src/mongo/db/query/query_knobs.idl
+++ b/src/mongo/db/query/query_knobs.idl
@@ -29,8 +29,9 @@
 global:
   cpp_namespace: "mongo"
   cpp_includes:
-    - "mongo/db/query/plan_cache_size_parameter.h"
     - "mongo/db/query/sbe_plan_cache_on_parameter_change.h"
+    - "mongo/db/query/util/memory_util.h"
+    - "mongo/db/query/query_stats/query_stats_on_parameter_change.h"
     - "mongo/platform/atomic_proxy.h"
     - "mongo/platform/atomic_word.h"
 
@@ -675,7 +676,7 @@ server_parameters:
     set_at: [ startup, runtime ]
     cpp_varname: "internalQueryForceClassicEngine"
     cpp_vartype: AtomicWord<bool>
-    default: false
+    default: true
 
   internalQueryAppendIdToSetWindowFieldsSort:
     description: "If true, appends _id to the sort stage generated by desugaring $setWindowFields to
@@ -906,6 +907,69 @@ server_parameters:
         expr: 8 * 1024 * 1024 # 8MB
     default: 0
 
+  internalQueryStatsRateLimit:
+    description: "The maximum number of queries per second that are sampled for query stats.
+      If the rate of queries goes above this number, then rate limiting will kick in, and any
+      further queries will not be sampled. To sample all queries, this can be set to -1. This can be
+      set to 0 to turn queryStats off completely."
+    set_at: [ startup, runtime ]
+    cpp_varname: "internalQueryStatsRateLimit"
+    cpp_vartype: AtomicWord<int>
+    default: 0
+    validator:
+      gte: -1
+    on_update: query_stats_util::onQueryStatsSamplingRateUpdate
+
+  internalQueryStatsCacheSize:
+    description: "The maximum amount of memory that the system will allocate for the query queryStats
+      cache. This will accept values in either of the following formats:
+      1. <number>% indicates a percentage of the physical memory available to the process. E.g.: 15%.
+      2. <number>(MB|GB), indicates the amount of memory in MB or GB. E.g.: 1.5GB, 100MB.
+      The default value is 1%, which means 1% of the physical memory available to the process."
+    set_at: [ startup, runtime ]
+    cpp_varname: "internalQueryStatsCacheSize"
+    cpp_vartype: synchronized_value<std::string>
+    default: "1%"
+    on_update: query_stats_util::onQueryStatsStoreSizeUpdate
+    validator:
+      callback: query_stats_util::validateQueryStatsStoreSize
+
+  internalQueryStatsErrorsAreCommandFatal:
+    description: "Whether errors in the $queryStats stage cause the aggregation pipeline to
+      immediately fail and report the error. Note that this is always the case for debug builds."
+    set_at: [ startup, runtime ]
+    cpp_varname: "internalQueryStatsErrorsAreCommandFatal"
+    cpp_vartype: AtomicWord<bool>
+    default: false
+
+  internalQueryAggMulticastTimeoutMS:
+    description: "Timeout in MS for requests to shard servers when aggregations are sent to all shard servers"
+    set_at: [ startup ]
+    cpp_vartype: int
+    cpp_varname: internalQueryAggMulticastTimeoutMS
+    default: 60000
+    validator:
+      gte: 0
+  
+  internalQueryAggMulticastMaxConcurrency:
+    description: "Max number of concurrent requests when aggregations are sent to all shard servers"
+    set_at: startup
+    cpp_vartype: int
+    cpp_varname: internalQueryAggMulticastMaxConcurrency
+    default: 100
+    validator:
+      gte: 1
+
+  internalQuerySpillingMaxWaitTimeout:
+    description: "Timeout in MS that the storage engine will block a spilling operation when the
+      cache is under pressure."
+    set_at: [ startup, runtime ]
+    cpp_vartype: AtomicWord<int>
+    cpp_varname: internalQuerySpillingMaxWaitTimeout
+    default: 1000
+    validator:
+      gte: 0
+
 # Note for adding additional query knobs:
 #
 # When adding a new query knob, you should consider whether or not you need to add an 'on_update'