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Resolves #17: Update explain() output with user readable keys #208

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Resolves #17: Update explain() output with user readable keys #208

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Resolves #17: Update explain() output with user readable keys
drkannan Aug 26, 2019
d423bd5
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drkannan Aug 26, 2019
eb13a6c
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drkannan Sep 6, 2019
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drkannan Sep 11, 2019
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7 changes: 4 additions & 3 deletions src/QLPlan.actor.h
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Original file line number Diff line number Diff line change
Expand Up @@ -241,8 +241,9 @@ struct IndexScanPlan : ConcretePlan<IndexScanPlan> {
std::vector<std::string> matchedPrefix)
: cx(cx), index(index), begin(begin), end(end), matchedPrefix(matchedPrefix) {}
bson::BSONObj describe() override {
std::string bound_begin = begin.present() ? FDB::printable(begin.get()) : "-inf";
std::string bound_end = end.present() ? FDB::printable(end.get()) : "+inf";
// #17: Added decode_key_part to update explain output with user readable keys
std::string bound_begin = begin.present() ? DataValue::decode_key_part(begin.get()).toString() : "-inf";
std::string bound_end = end.present() ? DataValue::decode_key_part(begin.get()).toString() : "+inf";
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@apkar apkar Aug 29, 2019

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Shouldn't this be end.get() ?

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@apkar apkar Aug 29, 2019

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Also, this logic would work if there is only one dimension in the index. As decode_key_part assumes there is only one element in the key. It checks type on the first byte only. If you have a compound index, then the key could be multi element tuple and this would fail.

For example, following explain() would fail.

db.coll.create_index([('a', 1), ('b', 1)])
db.coll.find({'a': 'A', 'b': 64}).explain()

You can use decode_bytes() to create DataKey. Once you have DataKey, you can iterate over different elements in the key to print them by their type.

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@senthil-db-expert senthil-db-expert Aug 30, 2019

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Thanks @apkar . Will look into it.

return BSON(
// clang-format off
"type" << "index scan" <<
Expand Down Expand Up @@ -708,4 +709,4 @@ ACTOR Future<std::pair<int64_t, Reference<ScanReturnedContext>>> executeUntilCom
Reference<Plan> deletePlan(Reference<Plan> subPlan, Reference<UnboundCollectionContext> cx, int64_t limit);
Reference<Plan> flushChanges(Reference<Plan> subPlan);

#endif /* _QL_PLAN_ACTOR_H_ */
#endif /* _QL_PLAN_ACTOR_H_ */