I want to get the total number of the documents that exist in firestore.
I don't want to get the data only the total number of inside Products collection I have 200.000 items is that possible with Angular 4-5, not angular.js
Can someone expert tell me how I can achieve that ??
My code so far and is not work
get_total_messages() {
this.messages_collection = this.afs.collection<MessageEntity>('messages');
return this.messages_collection.snapshotChanges();
}
End this is how I try to get the data but is not what I want;
this.firebase_Service.get_total_messages().subscribe( data => {
console.log(data);
});
There is no API to get the count of the number of documents in a Firestore collection. This means that the only ways to get the count are:
Get all documents and count them client-side.
Store the count as a separate property and update that as you add/remove documents.
Both approaches are quite common in NoSQL databases, with the second of course being a lot more efficient as the number of documents grows.
Firebase provides a sample of using Cloud Functions to keep a counter. While this sample is written for the Firebase Realtime Database, it can easily be modified to work on Cloud Firestore too.
Firestore also provides documentation on running aggregation queries and running distributed counters. Both seem slightly more involved than the first sample I linked though.
this.firebase_Service.get_total_messages().subscribe( data=>this.totalnumber=data.length);
//now, you can get total number of messages
luckily , i've solved somehow using the code,
try this, and it works well .
this.db.collection('User').valueChanges()
.subscribe( result => {
console.log(result.length);
})
Related
I have a social network app.
I need to query the last Posts ordered by date from any people that i follow.
My working query so far is :
Query getRecentFriendsPost(List<String> followings, int postedDate) {
return getUsersCollection()
.where("uid", whereIn: followings)
.where("postedAt", isGreaterThanOrEqualTo: postedDate)
.orderBy("dateCreated", descending: true)
.limit(16);
}
This doesn't answer my needs unfortunately.
The followings list contains the userIDs that i follow, and the length can grow until thousands. Firestore support only 10 items in whereIn clause.
Second problem, if the length is 1000, it will cost 100x10 queries to split the followings list into block of 10 uids.
This is very expensive and slow.
I must use the whole followings list to be sure to not miss the most recents posts.
How can i perform such a query with Firestore ?
The followings list allows me to query the User object associated to the Post, if a Post is retrieved by the query.
Should i go for RealTime Database in such situation ? (If i should even keep Firebase products)
I did not find a better architecture either, if anyone knows how to improve this it would be much appreciated.
I have migrated my database to MongoDB and i am able to do so in one query.
Performances are not impacted before passing an array of 6000 values, after that it starts giving results in more than 100ms which remains perfectly fine for my use case.
I tried my best with the search function and not really getting the results I´m searching for.
At the moment I try to replicate a functionality for swiping profiles on a card stack. The profiles are loaded over a Firebase Firestore backend. The problem is, due to the geoFireStore query, I get with every load within a specific radius a whole bunch of documents and I would like to reduce the read amount directly in the query.
So what I'm trying to achieve is, that when I swiped a profile once (left or right) I never want to read it in the query again. In addition, to save reads, I don't want to do this client sided, it should be done in the query directly.
Firestore JSON structure at the moment:
Users (collection)
UIDs [documents]
name
active
match {map}
If the match map doesn't contain the own UID (if exist is null) then read in query, else when own UID exist in other user profile under the map match (boolean: true or false for liked or disliked) then don't show as query result.
My stream is built this way:
return geo
.collection(
collectionRef:
friendrCollection.where("active", isEqualTo: true).where("match.$uid", isNull: true))
.within(
center: geoFirePoint,
radius: suchRadius,
field: 'position',
strictMode: false)
.map(_friendrsGPSListFromSnapshot);
}
I am working on this for 3 weeks now and not getting the results I want :D
-Should I stay with firestore or better the real-time-database?
-How do I need to structure the data to get a "except" query working?
Right now it is like:
Collection: Users --> Documents: UIDs --> Match{ownUID}
Thanks in advance
Andreas :)
I still not managed to find a proper solution to reduce the number of unnecessary profile reads inside the firestore query.
Has anyone an idea to handle this part?
The only way I found was to lookup existing matches on the client side (extra firestore collection), but that means that I always have to load the whole bundle of profiles and throwing them away afterward :(
Thank you!
Andreas
I have an app that returns a list of health foods. There will be approximately 10000-20000 foods (documents) in the product collection.
These foods are queried by multiple fields using arrayContains. This may be categories, subcategories and when the user searches in the search bar it is an arrayContains on the keywords array.
With so many products I plan to paginate the results of query as I get the documents. The issue is that I need to know the amount of results to display the total of results to the user.
I have read that for a query you are charged one read and then if you get the documents then they are further charged per document. Is there a way of getting the number of results for a query without getting all the documents.
I have seen this answer here:
Get size of the query in Firestore
But in this example they say to use a counter which doesn't seem practical as I am using a query on keyword when the user searches and I am using a mixture of categories, subcategories when the user filters.
Thanks
With so many products I plan to paginate the results of query as I get the documents.
That's a very good decision since getting 10000-20000 foods (documents) at once is not an option. Reason one is the cost, it will be quite expensive and second is that you'll get an OutOfMemoryError when trying to load such enormous amount of data.
The issue is that I need to know the amount of results to display the total of results to the user.
There is no way in Firestore so you can know in advance the size of the result set.
Is there a way of getting the number of results for a query without getting all the documents.
No, you have to page through all the results that are returned by your query to get the total size.
But in this example they say to use a counter which doesn't seem practical as I am using a query on keyword when the user searches
That's correct, that solution doesn't fit your needs since it solves the problem of storing the number of all documents in a collection and not the number of documents that are returned by a query. As far as I know, it's just not scalable to provide that information, in the way this cloud hosted, NoSQL, realtime database needs to "massively scale".
For any future lurker, a "solution" to this problem is to paginate results with a cursor until the query doesn't return any more documents. When the query snapshot is empty, return undefined for your cursor and handle from there:
const LIMIT = 100
const offset = req.query.offset
const results = db.collection(COLLECTION)
.offset(offset)
.limit(LIMIT)
.get()
const docs = results.docs.map(doc => doc.data())
res.status(200).send({
data: docs,
// Return the next offset or undefined if no docs are returned anymore.
offset: docs.length > 0 ? offset + LIMIT : undefined
})
I've been working with Google Cloud Firestore. I'm about to import 13000+ records from a CSV to the firestore back-end. I'll be using this collection for look up and auto-completion purposes.
I'm curious and concerned to know if this is a good idea. Also, I'm looking for some suggestions on what techniques should I be using to make retrieval of this this data as efficient as possible. I'm working with Angular 5 and using AngularFire2 to connect with Firestore.
The document itself is really small such as:
{
address: {
state: "NSW"
street: "19 XYZ Road"
suburb: "Darling Point"
},
user: {
name: "ABC",
company: "Property Management Company"
}
file_no: "AB996"
}
Most of the searching would be based on file_no property of the document.
Update
I just imported all 13k+ records to Firestore. It is really efficient. However, I have one issue. After importing the records, I'm getting the message on my Firestore console that my daily limit for Read Operations is reached (0.05 of 0.05 Million Ops). I just wrote data and displayed those records in a Data Table. I used the following query:
this.propertyService
.getSnapshotChanges()
.subscribe(properties => {
this.properties = properties;
this.loadingIndicator = false;
});
getSnapshotChanges(): Observable < any > {
return this.afs.collection(this.propertiesCollection).snapshotChanges()
.map((actions) => {
return actions.map((snapshot) => {
const data = snapshot.payload.doc.data();
data.id = snapshot.payload.doc.id;
return data;
});
});
}
How dos this makes my reading limit exceed?
The number of documents in a collection is of no consequence when you use Cloud Firestore. That's actually one of its bigger perks: no matter how many documents are in a collection, the queries will take the same amount of time.
Say you add 130 document and (for sake of example) it takes 1 second to get 10 documents out of it. That's the performance you'll get no matter how many documents are in the collection. So with 1300 documents it will also take 1 second, with 13K it will take 1 second, and with 13M, it will also take 1 second.
The problem more developers run into is to make their use-cases fit within the API of Firestore. For example: the only way to search for strings is with a so-called prefix match, there is no support for full-text search. This means that you can search for Prop* and find Property Management Company, but not for *Man* to find it.
I've read almost everywhere about structuring one's Firebase Database for efficient querying, but I am still a little confused between two alternatives that I have.
For example, let's say I want to get all of a user's "maxBenchPressSessions" from the past 7 days or so.
I'm stuck between picking between these two structures:
In the first array, I use the user's id as an attribute to index on whether true or false. In the second, I use userId as the attribute NAME whose value would be the user's id.
Is one faster than the other, or would they be indexed a relatively same manner? I kind of new to database design, so I want to make sure that I'm following correct practices.
PROGRESS
I have come up with a solution that will both flatten my database AND allow me to add a ListenerForSingleValueEvent using orderBy ONLY once, but only when I want to check if a user has a session saved for a specific day.
I can have each maxBenchPressSession object have a key in the format of userId_dateString. However, if I want to get all the user's sessions from the last 7 days, I don't know how to do it in one query.
Any ideas?
I recommend to watch the video. It is told about the structuring of the data very well.
References to the playlist on the firebase 3
Firebase 3.0: Data Modelling
Firebase 3.0: Node Client
As I understand the principle firebase to use it effectively. Should be as small as possible to query the data and it does not matter how many requests.
But you will approach such a request. We'll have to add another field to the database "negativeDate".
This field allows you to get the last seven entries. Here's a video -
https://www.youtube.com/watch?v=nMR_JPfL4qg&feature=youtu.be&t=4m36s
.limitToLast(7) - 7 entries
.orderByChild('negativeDate') - sort by date
Example of a request:
const ref = firebase.database().ref('maxBenchPressSession');
ref.orderByChild('negativeDate').limitToLast(7).on('value', function(snap){ })
Then add the user, and it puts all of its sessions.
const ref = firebase.database().ref('maxBenchPressSession/' + userId);
ref.orderByChild('negativeDate').limitToLast(7).on('value', function(snap){ })