SERVER-49726 Add test for SBE generic scan when static limit reached

Author: alyacb

jstests/core/index_bounds_static_limit.js

@@ -0,0 +1,57 @@
+// Validate that generic index scan is used in SBE once max limit for statically generated intervals
+// is reached.
+
+(function() {
+"use strict";
+
+load("jstests/libs/analyze_plan.js");  // For explain helpers.
+
+const isSBEEnabled = db.adminCommand({
+                           getParameter: 1,
+                           internalQueryEnableSlotBasedExecutionEngine: 1
+                       }).internalQueryEnableSlotBasedExecutionEngine;
+
+if (!isSBEEnabled) {
+    // This test is only relevant when SBE is enabled.
+    return;
+}
+
+const coll = db.index_bounds_static_limit;
+coll.drop();
+
+assert.commandWorked(coll.createIndex({a: 1, b: 1, c: 1, d: 1, e: 1}));
+
+// Save the old limit so it can be restored once the tests completes.
+const staticLimit = db.adminCommand({
+                          getParameter: 1,
+                          internalQuerySlotBasedExecutionMaxStaticIndexScanIntervals: 1
+                      }).internalQuerySlotBasedExecutionMaxStaticIndexScanIntervals;
+
+const setStaticLimit = function(limit) {
+    return db.adminCommand(
+        {setParameter: 1, internalQuerySlotBasedExecutionMaxStaticIndexScanIntervals: limit});
+};
+
+try {
+    // Verify that when the number of statically generated single interval bounds is less than the
+    // static limit, the optimized plan is used.
+    const optimized =
+        coll.find({a: {$in: [1, 2, 3]}, b: {$in: [10, 11, 12]}, c: {$in: [42]}, d: {$lt: 3}})
+            .explain("executionStats")
+            .executionStats.executionStages;
+    assert(planHasStage(db, optimized, "ixseek"), optimized);
+    assert(!planHasStage(db, optimized, "chkbounds"), optimized);
+
+    // Verify that when the number of statically generated single interval bounds is greater than
+    // the static limit, the generic plan is used.
+    setStaticLimit(2);
+    const generic =
+        coll.find({a: {$in: [1, 2, 3]}, b: {$in: [10, 11, 12]}, c: {$in: [42]}, d: {$lt: 3}})
+            .explain("executionStats")
+            .executionStats.executionStages;
+    assert(planHasStage(db, generic, "chkbounds"), generic);
+    assert(planHasStage(db, generic, "ixseek"), generic);
+} finally {
+    setStaticLimit(staticLimit);
+}
+})();

jstests/libs/analyze_plan.js

@@ -30,6 +30,22 @@ function getPlanStages(root, stage) {
         results = results.concat(getPlanStages(root.queryPlanner.winningPlan, stage));
     }
 
+    if ("thenStage" in root) {
+        results = results.concat(getPlanStages(root.thenStage, stage));
+    }
+
+    if ("elseStage" in root) {
+        results = results.concat(getPlanStages(root.elseStage, stage));
+    }
+
+    if ("outerStage" in root) {
+        results = results.concat(getPlanStages(root.outerStage, stage));
+    }
+
+    if ("innerStage" in root) {
+        results = results.concat(getPlanStages(root.innerStage, stage));
+    }
+
     if ("shards" in root) {
         if (Array.isArray(root.shards)) {
             results = root.shards.reduce(