Database
32 results found
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Allow configuration of 100mb memory limit per aggregation pipeline stage
In this old thread from 2016 (https://groups.google.com/forum/#!topic/mongodb-user/LCeFZZRz5EY) it was asked whether there was a way to increase the 100mb in memory limit of each stage of an aggregation pipeline. The responses centered around two points:
- If too much memory is used per aggregation pipeline stage then it will reduce performance for the overall MongoDB database, impacting other queries negatively.
- You can set allowDiskUse: true and revert to performing these pipeline stages on disk when they exceed 100mb.
I believe this subject needs to be revisited for the following reasons:
- “Too much memory” is very subjective, and the 100mb…
23 votes -
Add operator that would calculate distance between 2 geolocation points
It would be great to have operator that would calculate distance between 2 geolocation points, and not to do it manually with big aggregate queries.
I suggest to add 2 new operators that would calculate distance in two different ways, as discussed in this Community Post: https://www.mongodb.com/community/forums/t/how-to-calculate-distance-between-two-geolocation-points/173045
16 votes -
Support compound/multiple grouping keys in $bucket
We often need to compute statistical/summarizing aggregations grouped by more than one field where all fields are of a $bucket-able type.
An example, would be to count all orders grouped by their status and some custom time ranges of their creation date.
This can be achieved by using $group in combination with a $switch expression (sometimes simplified with $trunc), however, that is cumbersome and prevents efficient grouping since e.g. no binary search can be employed to identify the bucket boundaries efficiently.The query syntax of $bucket would not need to change much. It would simply need to allow for nested…
6 votes -
Handle Daylight Saving Time when $densify is used on a date field
When using "day" as "unit" for a $densify pipeline stage on a date field, the date is always advanced of 24 hours. This is however not always the expected result in timezones in which the year has one 23-hour and one 25-hour long day, because of Daylight Saving Time.
It would be useful to have the possibility to pass an optional timezone parameter in the $densify stage and, when present, have the stage account for these exceptions when appropriate.
Here follows an example.
Assume we have a collection containing the following documents:
…db.densifyDateExample.insertMany([ {_id: "a", d: ISODate("2022-10-28T22:00:00Z")}, {_id: "b", d:6 votes -
Raise the limit of 16 MB JSON between aggregation stages
When doing analytics, the 16 MB JSON limit between aggregation stages restricts the ability to process large amount of data. allowDiskUse does not help with all the various $operators and stages that we use. See ticket 00774514 for details.
4 votes -
Document scoped RBAC - Permission for collection document fields
Roles and accesses can be defined on the basis of collections that define roles for users.
It would be nice if these access permissions could be made within the scope of the fields under the collection and the query results would be returned accordingly.Current:
privileges: [
{ resource: { db: "users", collection: "user" }, actions: [ "find"] },
}
Expected:
{ resource: { db: "users", collection: "user", field: "email" }, actions: [ "find"] },
3 votes -
`$getField` to work with a dynamic `field`
Currently
$getFieldworks only whenfieldresolves at query-compile-time to a string. It would be nice if it worked also whenfieldresolves to a string at runtime.See this Jira ticket - https://jira.mongodb.org/browse/SERVER-67030
3 votes -
$merge
Report number of docs matched, merged, skipped, etc. from a $merge stage. Alternatively, return the merged doc results as a pipeline result to pass to additional stages.
2 votes -
geo
It would be nice to get the length of an LineString of a geo-json object or the possibility to write an aggregation to calculate it.
2 votes -
support $lookup for update aggregation
We frequently denormalise either full documents or subsets to different documents in order to speed up reading, create indexes or paginate/sort on fields.
Consider a user collection and a task collection, if a task can be assigned to the user, it makes sense to just put the user document on the task they are assigned. But an update to a user now requires you to update the user both in the user collection and all tasks with that user in the tasks collection.
This can be achieved but does introduce some complexity, however the introduction of updates using aggregation pipelines…
2 votes -
$group all fields
$group should have the ability to allow specifying all fields in a document (without explicitly defining them all, which can lead to duplicating dozens of lines just to do "key: $first")
This will help users that use $unwind and then want to $group the results without having to do a subsequent $lookup and $mergeObjects (or similar) to get the final document structure they're looking for.
1 vote -
Flatten arrays in group stage
Have group operators to flatten document arrays into a single one with or without repeated elements.
So ->
doc1 = {arr: [1,2,3,4], gr: "group"}, doc2 = {arr: [5, 6, 7, 8], gr: "group"}
{$group: {id: "$gr", arrays: {$***: "$arr"} } }
=>
{id: "gr", arrays: [1, 2, 3, 4, 5, 6, 7, 8]}1 vote -
Add SHA2, SHA3 and ECDSA functions to agg framework
It is very useful (and valuable security-wise) to be able to reverify hashes and signatures "on-engine" instead of dragging material out to a client app and running the algo there. The implementations are straightforward and everywhere now so it's not a huge lift for the backend. Example use:
aggregate([
{$match: whatever},
{$addFields: {
hashok: {$cond: [ {$eq: [ {$sha3: "path.to.struct"}, "path.to.stored.sha3"} ], 1, 0},
sigok: { $verify: { sig: "path.to.sig", pubkey: "path.to.pubkey", algo: "name of curve to use eg. SECP256k1}}
}
])
The digest function would operate on the raw BSON behind the scenes.1 vote -
Improve the mongo query language
Sometimes I find Mongo query language as not put very well together, sometimes it feels like a patch job. It would be nice, if you could make you query language easier to reason about. It would be awesome, if you could introduce fluent style api builder instead of building bson documents.
1 vote -
Add functionality to specify the readConcern level at db.collection.findOne()
Add functionality to specify the readConcern at db.collection.findOne(). At the version 5.0.14 it's not supported.
1 vote -
Add hash function (eg. md5) to aggregation pipeline
I would like to implement hash-based sharding in my own application on top of MongoDB. For that purpose, I would like to pull a stable pseudorandom subset of documents into each of my servers, and I would like to do so without enlarging the documents by adding additional fields, and without using JavaScript in the aggregation pipeline (for performance reasons).
The idea: add a hash function, such as md5, to aggregation pipelines. The function would accept an object/array containing the data to be hashed, and would return the hash, ideally as a number.
1 vote -
$dateDiff operator should be useful to calculate age
In the documentation it says: " For example, two dates that are 18 months apart would return 1 year difference instead of 1.5 years.". But if startDate is 2021-08-01 and endDate is 2023-02-01, the result is 2 years difference. I think it should be good if this operator could be used to calculate the age.
1 vote -
$currentDate option to only update if the document was modified
A common pattern in a data model is to have a field that denotes when the data was last modified. For this example, let this field be called "updated". I want to toggle a field on a document called "enabled", and if the value is modified I also want to update the "updated" field.
This behavior is possible right now via a comment shown in SERVER-42084, but ONLY if we include the entire document, which is not acceptable when you only want to modify a single field. This document could have other fields that are numeric and are updated atomically,…
1 vote -
Need an array query operator like elem match which matches all array nested object instead of at least one array element
as per documentation elem match query matches at least one match in array of nested object,
same we need a array query operator which returns the whole document only if elem match like criteria matches all elements in array of nested objects.
I have gone through usecase of $all with $elemMatch but it behaviour different it is like $and with $elemMatch instead excepted behaviour i am asking or excepting mentioned earlier.
https://www.mongodb.com/docs/manual/reference/operator/query/all/#use--all-with--elemmatch
https://www.mongodb.com/docs/manual/reference/operator/query/elemMatch/1 vote -
Make redundant createView() a no-op
If I call createView() with params that match an existing view (in name and all other attributes), it returns an error. It'd be more convenient if the call simply succeeded without doing any work. The behavior I propose is analogous to the way that createIndex() behaves. With the current behavior my only choices are to (1) unconditionally drop and recreate the view, or (2) read the current view definition and see whether it matches the definition I want. The first choice is unacceptable because for a period of time (albeit a short one) the view won't exist and queries that…
1 vote
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