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Type:
Bug
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Resolution: Fixed
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Priority:
Major - P3
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Affects Version/s: None
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Component/s: None
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Labels:None
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Query Execution
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Minor Change
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ALL
mongos returns an empty cursor with this aggregation when the db does not exist.
db.aggregate([{$match: {size: "medium"}}, {$documents: [{_id: 1, size: "medium"}, {_id: 2}]}]);
This command should return an error since $documents can only be used in the first stage in a pipeline.
Additionally, mongos will return an empty cursor with this aggregation. This aggregation should also raise an error since $unionWith must be used with a collection.
db.aggregate([
{
$unionWith: {
pipeline: [{ $documents: {$map: {input: {$range: [0, 5]}, in : {x: "$$this"}}}}]
}
},
{ $group: {_id: "$x", x: {$first: "$x"}}},
{ $project: {_id: 0}},
])
.toArray();
Discovered in SERVER-63811. The empty cursor is being returned by this logic:
if (executionNsRoutingInfoStatus.isOK()) {
cm = std::move(executionNsRoutingInfoStatus.getValue());
} else if (!(hasChangeStream &&
executionNsRoutingInfoStatus == ErrorCodes::NamespaceNotFound)) {
appendEmptyResultSetWithStatus(
opCtx, namespaces.requestedNss, executionNsRoutingInfoStatus.getStatus(), result);
return Status::OK();
}
However validation checks should have occurred before this logic and returned an error.
- is depended on by
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COMPASS-7278 Investigate changes in SERVER-69836: mongos doesn't raise validation errors but returns empty cursors when the database doesn't exist
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- Closed
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- is related to
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- Closed
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- related to
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- Blocked
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