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Diffstat (limited to 'src/mongo/db/query/indexability.h')
| -rw-r--r-- | src/mongo/db/query/indexability.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/mongo/db/query/indexability.h b/src/mongo/db/query/indexability.h index 7e543da4a2d..48b9e0d91b4 100644 --- a/src/mongo/db/query/indexability.h +++ b/src/mongo/db/query/indexability.h @@ -55,6 +55,26 @@ public: } /** + * Type bracketing does not apply to internal Expressions. This could cause the use of a sparse + * index return incomplete results. For example, a query {$expr: {$lt: ["$missing", "r"]}} would + * expect a document like, {a: 1}, with field "missing" missing be returned. However, a sparse + * index, {missing: 1} does not index the document. Therefore, we should ban use of any sparse + * index on following expression types. + */ + static bool nodeSupportedBySparseIndex(const MatchExpression* me) { + switch (me->matchType()) { + case MatchExpression::INTERNAL_EXPR_EQ: + case MatchExpression::INTERNAL_EXPR_GT: + case MatchExpression::INTERNAL_EXPR_GTE: + case MatchExpression::INTERNAL_EXPR_LT: + case MatchExpression::INTERNAL_EXPR_LTE: + return false; + default: + return true; + } + } + + /** * This array operator doesn't have any children with fields and can use an index. * * Example: a: {$elemMatch: {$gte: 1, $lte: 1}}. |