Pg-promise performance boost : Multiple inserts with multiple update parameters

Question

I am implementing Vitaly's pg-promise performance patterns, as advised here and there.

Here is my code :

for (var i=0;i<chunkedData.length;i++){

    var insertData = chunkedData[i].map(function (d) {
        return {
            application_id: d.application_id,
            country_id: d.country_id,
            collection_id: collectionId
        };
    });

    // Would need to make a loop here, and thus turning the result into an array
    var updateData = {
        application_id: chunkedData[i][j].application_id,
        country_id: chunkedData[i][j].country_id,
        collection_id: collectionId
    };

      var query = h.insert(insertData, cs) +
          " ON CONFLICT ON CONSTRAINT application_average_ranking_application_id_country_id_colle_key DO UPDATE SET " +
          h.sets(updateData, cs);

    db.none(query)
        .then(data => {
            console.log('success');
        })
        .catch(error=> {
            console.log('insert error : ' + error);
        });
}

My problem is that insertData is an Array of Objects, and the library's insert helper builds an insert request using that Array, as specified in pg-promise API. Whereas updateData must be a simple Object.

I would like that when :

ON CONFLICT ON CONSTRAINT constraintName DO UPDATE 

is triggered, the update values match the corresponding object in 'insertData' array.

How can I work around that problem ?

I've tried to put everything in a loop, but it leaks memory like crazy, and well, I lose the benefits of the pattern...

EDIT :

I want my query to be the equivalent of :

 var inserts = data.map(entry => {
    return t.none(" INSERT INTO application_average_ranking (application_id,country_id,collection_id) VALUES ($1,$2,$3)" +
                 " ON CONFLICT ON CONSTRAINT application_average_ranking_application_id_country_id_colle_key" +
                 " DO UPDATE SET country_id=$2,collection_id=$3",
                 [entry.application_id,entry.country_id,collectionId]
    );
});

In that case when Update is called, the parameters refer to values originally proposed for insertion.

Answer 1

Your task requires a static SQL to implement that kind of logic, by using EXCLUDED as the table reference with rows excluded due to the conflict:

var sqlConflict = " ON CONFLICT ON CONSTRAINT" +
    " application_average_ranking_application_id_country_id_colle_key" +
    " DO UPDATE SET application_id = excluded.application_id" +
    " country_id = excluded.country_id, collection_id = excluded.collection_id";

var insertData = chunkedData.map(function (d) {
    return {
        application_id: d.application_id,
        country_id: d.country_id,
        collection_id: collectionId
    };
});

var query = h.insert(insertData, cs) + sqlConflict;

db.none(query)
    .then(data => {
        console.log('success');
    })
    .catch(error=> {
        console.log('insert error : ' + error);
    });

UPDATE

And in case your static list of excluded fields is too long and you want to simplify it, you can can always rely on flexibility of the helpers methods:

// or pull them from an object using `Object.keys(obj)`:
var cols = ['application_id', 'country_id', 'collection_id'];

var sets = pgp.helpers.sets({}, cols.map(c=> ({
    name: c, mod: '^', def: 'excluded.' + pgp.as.name(c)
})));

console.log(sets);
//=> "application_id"=excluded."application_id","country_id"=excluded."country_id",
//   "collection_id"=excluded."collection_id"

// or its simple JavaScript equivalent:
var sets = cols.map(c=> {
    var name = pgp.as.name(c);
    return name + '=excluded.' + name;
}).join();

UPDATE

With version 7.3.0 of the library and later, you should use method assignColumns to generate all of the excluded sets, like this:

cs.assignColumns({from: 'EXCLUDED'})
//=> "application_id"=EXCLUDED."application_id","country_id"=EXCLUDED."country_id","collection_id"=EXCLUDED."collection_id"

or, if you want to skip application_id, then you can do:

cs.assignColumns({from: 'EXCLUDED', skip: 'application_id'})
//=> "country_id"=EXCLUDED."country_id","collection_id"=EXCLUDED."collection_id"

See ColumnSet.assignColumns