SERVER-56083 [SBE] Expressions unsupported in SBE for agg operations prevent SBE engine from being selected even if not pushed down

1 files changed, 57 insertions, 0 deletions

diff --git a/jstests/noPassthroughWithMongod/sbe_agg_pushdown.js b/jstests/noPassthroughWithMongod/sbe_agg_pushdown.js
new file mode 100644
index 00000000000..c3f8d9259b2
--- /dev/null
+++ b/jstests/noPassthroughWithMongod/sbe_agg_pushdown.js
@@ -0,0 +1,57 @@
+// Tests aggregation queries containing a mix of SBE supported and unspported expressions execute
+// the pushed down query with SBE.
+// TODO: Remove this file when all agg expressions are supported by SBE.
+
+(function() {
+"use strict";
+
+load("jstests/libs/sbe_util.js");  // For checkSBEEnabled.
+
+const isSBEEnabled = checkSBEEnabled(db);
+if (!isSBEEnabled) {
+    jsTestLog("Skipping test because the SBE feature flag is disabled");
+    return;
+}
+
+const coll = db.jstests_sbe_pushdown;
+coll.drop();
+
+// Helper that runs a 'pipeline' with explain mode to determine if SBE was used to execute the
+// pushed down query or not. It does this by checking the 'explainVersion' of the plan against the
+// 'expectedExplainVersion' input. If the plan has an 'explainVersion' of "2", then SBE was used to
+// execute the pushed down query. Otherwise, an 'explainVersion' of "1" means the classic engine was
+// used to execute the pushed down query.
+function assertPushdownQueryExecMode(pipeline, expectedExplainVersion) {
+    assert(expectedExplainVersion === "1" || expectedExplainVersion === "2");
+    const actualExplainVersion = coll.explain().aggregate(pipeline).explainVersion;
+    assert.eq(actualExplainVersion, expectedExplainVersion);
+}
+
+assert.commandWorked(coll.insertMany([
+    {_id: 0, a: 1, b: ISODate("2021-04-28T00:00:00Z")},
+    {_id: 1, a: 2, b: ISODate("2021-04-28T10:00:00Z")},
+    {_id: 2, a: 3, b: ISODate("2021-04-28T20:00:00Z")},
+]));
+
+// Test query with no supported expressions is executed with the classic engine.
+assertPushdownQueryExecMode([{$project: {_id: 0, c: {$dateToString: {date: "$b"}}}}], "1");
+
+// Test query that contains an expression unsupported by SBE that isn't pushed down. In this case,
+// we still expect SBE to be used if the unsupported expression isn't pushed down.
+assertPushdownQueryExecMode(
+    [
+        {$match: {a: 2}},
+        {$_internalInhibitOptimization: {}},
+        {$project: {_id: 0, c: {$dateToString: {date: "$b"}}}}
+    ],
+    "2");
+
+// Test query with an unsupported expression in a $project stage that's pushed down executes with
+// the classic engine.
+assertPushdownQueryExecMode(
+    [{$match: {a: 2}}, {$project: {_id: 0, c: {$dateToString: {date: "$b"}}}}], "1");
+
+// Test query with fully supported expressions are executed with SBE when pushed down.
+assertPushdownQueryExecMode(
+    [{$match: {$expr: {$eq: ["$b", {$dateFromParts: {year: 2021, month: 4, day: 28}}]}}}], "2");
+}());