Couchbase Update query divide - nosql

Question

I am trying to update the document using the UPDATE query statement on the couchbase.
EX)
UPDATE Users SET cityIndex = 1 where Users.city= "NewYork";
There was so much data that I wanted to divide 3,000 to 4,000 and proceed with the UPDATE. How should I proceed?
There is PRIMARY INDEX.

Answer 1

The Eventing Function method that vsr alluded too is quite simple (7 lines sans comments) and you run it as a one-off point tool deploying it from Everything. Note there is no need for any index for this to work.
// To run configure the settings for this Function, UpdateAllCityIndex, as follows:
//
// Version 7.0+
// "Listen to Location"
// bulk.data.yourcollection
// "Eventing Storage"
// rr100.eventing.metadata
// Binding(s)
// 1. "binding type", "alias name...", "bucket.scope.collection", "Access"
// ---------------------------------------------------------------------------
// "bucket alias", "src_col", "bulk.data.Users", "read and write"
//
// Version 6.X
// "Source Bucket"
// yourbucket
// "MetaData Bucket"
// metadata
// Binding(s)
// 1. "binding type", "alias name...", "bucket", "Access"
// ---------------------------------------------------------------------------
// "bucket alias", "src_col", "Users", "read and write"
//
// For more performance set the workers to the number of physical cores
function OnUpdate(doc, meta) {
// only process documents with the city field
if (!doc.city) return;
// only update New York if cityIndex isn't already 1 or does not exist
if ( doc.city === "NewYork" && (!doc.cityIndex || doc.cityIndex !== 1 )) {
doc.cityIndex = 1;
// write back the updated doc via the alias
src_col[meta.id] = doc;
}
}

Answer 2

Option 1)
You can use couchbase eventing
case 2 of https://docs.couchbase.com/server/current/eventing/eventing-example-data-enrichment.html
https://docs.couchbase.com/server/current/eventing/eventing-examples.html
Option 2)
CREATE INDEX ix1 ON Users (city, cityIndex);
UPDATE Users AS u
SET u.cityIndex = 1
WHERE u.city = "NewYork" AND u.cityIndex != 1
LIMIT 4000;

Answer 3

Using a primary index, you can issues multiple queries on a (presumably stable primary index) and iterate over it. Little bit more complicated, but generalized.
rq is the bucket, s is the scope, t1 is the collection.
create collection rq.s.t1;
create primary index on rq.s.t1;
First query:
UPDATE rq.s.t1 USE KEYS [(
SELECT META().id
FROM rq.s.t1
ORDER BY META().id
LIMIT 10)] SET x = 1 RETURNING MAX(META().id);
Second to N query until you're done (nothing gets returned):
Take the max value of meta().id from the previous query (see the WHERE clause)
UPDATE rq.s.t1 USE KEYS [(
SELECT RAW META().id
FROM rq.s.t1
WHERE META().id > "007dd444-fa39-498f-b070-6cd0d41abe3d"
ORDER BY META().id
LIMIT 10)] SET x = 1 RETURNING META().id;
You can optimize this loop by setting the initial meta().id to compare against "".