This PR adds **atomic** `$push` **support for array fields**. It makes
it possible to safely append new items to arrays, which is especially
useful when running tasks in parallel (like job queues) where multiple
processes might update the same record at the same time. By handling
pushes atomically, we avoid race conditions and keep data consistent -
especially on postgres, where the current implementation would nuke the
entire array table before re-inserting every single array item.
The feature works for both localized and unlocalized arrays, and
supports pushing either single or multiple items at once.
This PR is a requirement for reliably running parallel tasks in the job
queue - see https://github.com/payloadcms/payload/pull/13452.
Alongside documenting `$push`, this PR also adds documentation for
`$inc`.
## Changes to updatedAt behavior
https://github.com/payloadcms/payload/pull/13335 allows us to override
the updatedAt property instead of the db always setting it to the
current date.
However, we are not able to skip updating the updatedAt property
completely. This means, usage of $push results in 2 postgres db calls:
1. set updatedAt in main row
2. append array row in arrays table
This PR changes the behavior to only automatically set updatedAt if it's
undefined. If you explicitly set it to `null`, this now allows you to
skip the db adapter automatically setting updatedAt.
=> This allows us to use $push in just one single db call
## Usage Examples
### Pushing a single item to an array
```ts
const post = (await payload.db.updateOne({
data: {
array: {
$push: {
text: 'some text 2',
id: new mongoose.Types.ObjectId().toHexString(),
},
},
},
collection: 'posts',
id: post.id,
}))
```
### Pushing a single item to a localized array
```ts
const post = (await payload.db.updateOne({
data: {
arrayLocalized: {
$push: {
en: {
text: 'some text 2',
id: new mongoose.Types.ObjectId().toHexString(),
},
es: {
text: 'some text 2 es',
id: new mongoose.Types.ObjectId().toHexString(),
},
},
},
},
collection: 'posts',
id: post.id,
}))
```
### Pushing multiple items to an array
```ts
const post = (await payload.db.updateOne({
data: {
array: {
$push: [
{
text: 'some text 2',
id: new mongoose.Types.ObjectId().toHexString(),
},
{
text: 'some text 3',
id: new mongoose.Types.ObjectId().toHexString(),
},
],
},
},
collection: 'posts',
id: post.id,
}))
```
### Pushing multiple items to a localized array
```ts
const post = (await payload.db.updateOne({
data: {
arrayLocalized: {
$push: {
en: {
text: 'some text 2',
id: new mongoose.Types.ObjectId().toHexString(),
},
es: [
{
text: 'some text 2 es',
id: new mongoose.Types.ObjectId().toHexString(),
},
{
text: 'some text 3 es',
id: new mongoose.Types.ObjectId().toHexString(),
},
],
},
},
},
collection: 'posts',
id: post.id,
}))
```
---
- To see the specific tasks where the Asana app for GitHub is being
used, see below:
- https://app.asana.com/0/0/1211110462564647
Previously, `db.deleteMany` on postgres resulted in 2 roundtrips to the
database (find + delete with ids). This PR passes the where query
directly to the `deleteWhere` function, resulting in only one roundtrip
to the database (delete with where).
If the where query queries other tables (=> joins required), this falls
back to find + delete with ids. However, this is also more optimized
than before, as we now pass `select: { id: true }` to the findMany
query.
---
- To see the specific tasks where the Asana app for GitHub is being
used, see below:
- https://app.asana.com/0/0/1210871676349299
Currently, an optimized DB update (simple data => no
delete-and-create-row) does the following:
1. sql UPDATE
2. sql SELECT
This PR reduces this further to one single DB call for simple
collections:
1. sql UPDATE with RETURNING()
This only works for simple collections that do not have any fields that
need to be fetched from other tables. If a collection has fields like
relationship or blocks, we'll need that separate SELECT call to join in
the other tables.
In 4.0, we can remove all "complex" fields from the jobs collection and
replace them with a JSON field to make use of this optimization
---
- To see the specific tasks where the Asana app for GitHub is being
used, see below:
- https://app.asana.com/0/0/1210803039809814
