Revert "SERVER-65884 $lookup from ts optimize $sequentialCache"

This reverts commit 252235fda4d45e85db342bb6437b1587b980b1ed.

3 files changed, 0 insertions, 121 deletions

diff --git a/jstests/core/timeseries/timeseries_lookup.js b/jstests/core/timeseries/timeseries_lookup.js
index d95bf137f5a..75a80a48177 100644
--- a/jstests/core/timeseries/timeseries_lookup.js
+++ b/jstests/core/timeseries/timeseries_lookup.js
@@ -85,99 +85,6 @@ TimeseriesTest.run((insert) => {
             assert.eq({host: "host_" + i, matchedB: entryCountPerHost[i]}, results[i], results);
         }
 
-        // Equality Match With Let (uncorrelated)
-        // Make sure injected $sequentialDocumentCache (right after unpack bucket stage)
-        // in the inner pipeline is removed.
-        results = collA.aggregate([
-            {
-                $lookup: {
-                    from: collB.getName(),
-                    let: {"outer_hostname": "$tags.hostname"},
-                    pipeline: [
-                        // $match will be pushed before unpack bucket stage
-                        {$match: {$expr: {$eq: ["$$outer_hostname", hosts[0].tags.hostname]}}},
-                    ],
-                    as: "matchedB"
-                }
-            }, {
-                $project: {
-                    _id: 0,
-                    host: "$tags.hostname",
-                    matchedB: {
-                        $size: "$matchedB"
-                    }
-                }
-            },
-            {$sort: {host: 1}}
-        ]).toArray();
-        assert.eq(numHosts, results.length, results);
-        for (let i = 0; i < numHosts; i++) {
-            const matched = i === 0 ? numDocs : 0;
-            assert.eq({host: "host_" + i, matchedB: matched}, results[i], results);
-        }
-
-        // Equality Match With Let (uncorrelated)
-        // Make sure injected $sequentialDocumentCache in the inner pipeline is removed.
-        // $sequentialDocumentCache is not located right after unpack bucket stage.
-        results = collA.aggregate([
-                    {
-                        $lookup: {
-                            from: collB.getName(),
-                            let: {"outer_hostname": "$tags.hostname"},
-                            pipeline: [
-                                {$match: {$expr: {$eq: ["$$outer_hostname", hosts[0].tags.hostname]}}},
-                                {$set: {foo: {$const: 123}}},  // uncorrelated
-                            ],
-                            as: "matchedB"
-                        }
-                    }, {
-                        $project: {
-                            _id: 0,
-                            host: "$tags.hostname",
-                            matchedB: {
-                                $size: "$matchedB"
-                            }
-                        }
-                    },
-                    {$sort: {host: 1}}
-                ]).toArray();
-        assert.eq(numHosts, results.length, results);
-        for (let i = 0; i < numHosts; i++) {
-            const matched = i === 0 ? numDocs : 0;
-            assert.eq({host: "host_" + i, matchedB: matched}, results[i], results);
-        }
-
-        // Equality Match With Let (correlated, no $match re-order)
-        // Make sure injected $sequentialDocumentCache in the inner pipeline is removed.
-        // $sequentialDocumentCache is located at the very end of pipeline.
-        results = collA.aggregate([
-            {
-                $lookup: {
-                    from: collB.getName(),
-                    let: {"outer_hostname": "$tags.hostname"},
-                    pipeline: [
-                        {$match: {$expr: {$eq: ["$$outer_hostname", hosts[0].tags.hostname]}}},
-                        {$set: {foo: "$$outer_hostname"}},  // correlated
-                    ],
-                    as: "matchedB"
-                }
-            }, {
-                $project: {
-                    _id: 0,
-                    host: "$tags.hostname",
-                    matchedB: {
-                        $size: "$matchedB"
-                    }
-                }
-            },
-            {$sort: {host: 1}}
-        ]).toArray();
-        assert.eq(numHosts, results.length, results);
-        for (let i = 0; i < numHosts; i++) {
-            const matched = i === 0 ? numDocs : 0;
-            assert.eq({host: "host_" + i, matchedB: matched}, results[i], results);
-        }
-
         // Unequal joins
         results = collA.aggregate([
             {
diff --git a/src/mongo/db/pipeline/document_source_internal_unpack_bucket.cpp b/src/mongo/db/pipeline/document_source_internal_unpack_bucket.cpp
index f3a96903a8e..272d7a1a80c 100644
--- a/src/mongo/db/pipeline/document_source_internal_unpack_bucket.cpp
+++ b/src/mongo/db/pipeline/document_source_internal_unpack_bucket.cpp
@@ -53,7 +53,6 @@
 #include "mongo/db/pipeline/document_source_match.h"
 #include "mongo/db/pipeline/document_source_project.h"
 #include "mongo/db/pipeline/document_source_sample.h"
-#include "mongo/db/pipeline/document_source_sequential_document_cache.h"
 #include "mongo/db/pipeline/document_source_single_document_transformation.h"
 #include "mongo/db/pipeline/document_source_sort.h"
 #include "mongo/db/pipeline/expression_context.h"
@@ -981,15 +980,6 @@ bool DocumentSourceInternalUnpackBucket::optimizeLastpoint(Pipeline::SourceConta
         tryInsertBucketLevelSortAndGroup(AccumulatorDocumentsNeeded::kLastDocument);
 }
 
-// Find $sequentialDocumentCache in the rest of the pipeline.
-Pipeline::SourceContainer::iterator findSequentialDocumentCache(
-    Pipeline::SourceContainer::iterator start, Pipeline::SourceContainer::iterator end) {
-    while (start != end && !dynamic_cast<DocumentSourceSequentialDocumentCache*>(start->get())) {
-        start = std::next(start);
-    }
-    return start;
-}
-
 Pipeline::SourceContainer::iterator DocumentSourceInternalUnpackBucket::doOptimizeAt(
     Pipeline::SourceContainer::iterator itr, Pipeline::SourceContainer* container) {
     invariant(*itr == this);
@@ -1085,18 +1075,6 @@ Pipeline::SourceContainer::iterator DocumentSourceInternalUnpackBucket::doOptimi
         }
 
         Pipeline::optimizeEndOfPipeline(itr, container);
-
-        // $sequentialDocumentCache is full pipeline context aware. The call to
-        // optimizeEndOfPipeline above isolates part of the pipeline and $sequentialDocumentCache
-        // optimization applies incorrectly. The second call to
-        // $sequentialDocumentCache->optimizeAt() is no-op, so it has to be forced.
-        auto cache = findSequentialDocumentCache(std::next(itr), container->end());
-        if (cache != container->end()) {
-            auto cacheDocSource =
-                dynamic_cast<DocumentSourceSequentialDocumentCache*>(cache->get());
-            cacheDocSource->forceOptimizeAt(cache, container);
-        }
-
         if (std::next(itr) == container->end()) {
             return container->end();
         } else {
diff --git a/src/mongo/db/pipeline/document_source_sequential_document_cache.h b/src/mongo/db/pipeline/document_source_sequential_document_cache.h
index 743394ac853..4e81390d4ef 100644
--- a/src/mongo/db/pipeline/document_source_sequential_document_cache.h
+++ b/src/mongo/db/pipeline/document_source_sequential_document_cache.h
@@ -97,12 +97,6 @@ public:
         return newStage;
     }
 
-    Pipeline::SourceContainer::iterator forceOptimizeAt(Pipeline::SourceContainer::iterator itr,
-                                                        Pipeline::SourceContainer* container) {
-        _hasOptimizedPos = false;
-        return doOptimizeAt(itr, container);
-    }
-
 protected:
     GetNextResult doGetNext() final;
     Pipeline::SourceContainer::iterator doOptimizeAt(Pipeline::SourceContainer::iterator itr,