# Which Problems Are Solved
Zitadel currently uses 3 database pool, 1 for queries, 1 for pushing
events and 1 for scheduled projection updates. This defeats the purpose
of a connection pool which already handles multiple connections.
During load tests we found that the current structure of connection
pools consumes a lot of database resources. The resource usage dropped
after we reduced the amount of database pools to 1 because existing
connections can be used more efficiently.
# How the Problems Are Solved
Removed logic to handle multiple connection pools and use a single one.
# Additional Changes
none
# Additional Context
part of https://github.com/zitadel/zitadel/issues/8352
# Which Problems Are Solved
In eventstore queries with aggregate ID exclusion filters, filters on
events creation date where not passed to the sub-query. This results in
a high amount of returned rows from the sub-query and high overall query
cost.
# How the Problems Are Solved
When CreatedAfter and CreatedBefore are used on the global search query,
copy those filters to the sub-query. We already did this for the
position column filter.
# Additional Changes
- none
# Additional Context
- Introduced in https://github.com/zitadel/zitadel/pull/8940
Co-authored-by: Livio Spring <livio.a@gmail.com>
# Which Problems Are Solved
For truly event-based notification handler, we need to be able to filter
out events of aggregates which are already handled. For example when an
event like `notify.success` or `notify.failed` was created on an
aggregate, we no longer require events from that aggregate ID.
# How the Problems Are Solved
Extend the query builder to use a `NOT IN` clause which excludes
aggregate IDs when they have certain events for a certain aggregate
type. For optimization and proper index usages, certain filters are
inherited from the parent query, such as:
- Instance ID
- Instance IDs
- Position offset
This is a prettified query as used by the unit tests:
```sql
SELECT created_at, event_type, "sequence", "position", payload, creator, "owner", instance_id, aggregate_type, aggregate_id, revision
FROM eventstore.events2
WHERE instance_id = $1
AND aggregate_type = $2
AND event_type = $3
AND "position" > $4
AND aggregate_id NOT IN (
SELECT aggregate_id
FROM eventstore.events2
WHERE aggregate_type = $5
AND event_type = ANY($6)
AND instance_id = $7
AND "position" > $8
)
ORDER BY "position" DESC, in_tx_order DESC
LIMIT $9
```
I used this query to run it against the `oidc_session` aggregate looking
for added events, excluding aggregates where a token was revoked,
against a recent position. It fully used index scans:
<details>
```json
[
{
"Plan": {
"Node Type": "Index Scan",
"Parallel Aware": false,
"Async Capable": false,
"Scan Direction": "Forward",
"Index Name": "es_projection",
"Relation Name": "events2",
"Alias": "events2",
"Actual Rows": 2,
"Actual Loops": 1,
"Index Cond": "((instance_id = '286399006995644420'::text) AND (aggregate_type = 'oidc_session'::text) AND (event_type = 'oidc_session.added'::text) AND (\"position\" > 1731582100.784168))",
"Rows Removed by Index Recheck": 0,
"Filter": "(NOT (hashed SubPlan 1))",
"Rows Removed by Filter": 1,
"Plans": [
{
"Node Type": "Index Scan",
"Parent Relationship": "SubPlan",
"Subplan Name": "SubPlan 1",
"Parallel Aware": false,
"Async Capable": false,
"Scan Direction": "Forward",
"Index Name": "es_projection",
"Relation Name": "events2",
"Alias": "events2_1",
"Actual Rows": 1,
"Actual Loops": 1,
"Index Cond": "((instance_id = '286399006995644420'::text) AND (aggregate_type = 'oidc_session'::text) AND (event_type = 'oidc_session.access_token.revoked'::text) AND (\"position\" > 1731582100.784168))",
"Rows Removed by Index Recheck": 0
}
]
},
"Triggers": [
]
}
]
```
</details>
# Additional Changes
- None
# Additional Context
- Related to https://github.com/zitadel/zitadel/issues/8931
---------
Co-authored-by: adlerhurst <silvan.reusser@gmail.com>
# Which Problems Are Solved
We need a reliable way to lock events that are being processed as part
of a job queue. For example in the notification handlers.
# How the Problems Are Solved
Allow setting `FOR UPDATE [ NOWAIT | SKIP LOCKED ]` to the eventstore
query builder using an open transaction.
- NOWAIT returns an errors if the lock cannot be obtained
- SKIP LOCKED only returns row which are not locked.
- Default is to wait for the lock to be released.
# Additional Changes
- none
# Additional Context
- [Locking
docs](https://www.postgresql.org/docs/17/sql-select.html#SQL-FOR-UPDATE-SHARE)
- Related to https://github.com/zitadel/zitadel/issues/8931
# Which Problems Are Solved
Noisy neighbours can introduce projection latencies because the
projections only query events older than the start timestamp of the
oldest push transaction.
# How the Problems Are Solved
During push we set the application name to
`zitadel_es_pusher_<instance_id>` instead of `zitadel_es_pusher` which
is used to query events by projections.
ZITADEL CI/CD / compile (push) Blocked by required conditions
ZITADEL CI/CD / core-unit-test (push) Blocked by required conditions
ZITADEL CI/CD / core-integration-test (push) Blocked by required conditions
ZITADEL CI/CD / lint (push) Blocked by required conditions
ZITADEL CI/CD / container (push) Blocked by required conditions
ZITADEL CI/CD / e2e (push) Blocked by required conditions
ZITADEL CI/CD / release (push) Blocked by required conditions
Code Scanning / CodeQL-Build (go) (push) Waiting to run
Code Scanning / CodeQL-Build (javascript) (push) Waiting to run
# Which Problems Are Solved
Milestones used existing events from a number of aggregates. OIDC
session is one of them. We noticed in load-tests that the reduction of
the oidc_session.added event into the milestone projection is a costly
business with payload based conditionals. A milestone is reached once,
but even then we remain subscribed to the OIDC events. This requires the
projections.current_states to be updated continuously.
# How the Problems Are Solved
The milestone creation is refactored to use dedicated events instead.
The command side decides when a milestone is reached and creates the
reached event once for each milestone when required.
# Additional Changes
In order to prevent reached milestones being created twice, a migration
script is provided. When the old `projections.milestones` table exist,
the state is read from there and `v2` milestone aggregate events are
created, with the original reached and pushed dates.
# Additional Context
- Closes https://github.com/zitadel/zitadel/issues/8800
# Which Problems Are Solved
Float64 which was used for the event.Position field is [not precise in
go and gets rounded](https://github.com/golang/go/issues/47300). This
can lead to unprecies position tracking of events and therefore
projections especially on cockcoachdb as the position used there is a
big number.
example of a unprecies position:
exact: 1725257931223002628
float64: 1725257931223002624.000000
# How the Problems Are Solved
The float64 was replaced by
[github.com/jackc/pgx-shopspring-decimal](https://github.com/jackc/pgx-shopspring-decimal).
# Additional Changes
Correct behaviour of makefile for load tests.
Rename `latestSequence`-queries to `latestPosition`
# Which Problems Are Solved
Queriying events by an aggregate id can produce high loads on the
database if the aggregate id contains many events (count > 1000000).
# How the Problems Are Solved
Instead of using the postion and in_tx_order columns we use the sequence
column which guarantees correct ordering in a single aggregate and uses
more optimised indexes.
# Additional Context
Closes https://github.com/zitadel/DevOps/issues/50
Co-authored-by: Livio Spring <livio.a@gmail.com>
* fix(eventstore): prevent allocation of filtered events
Directly reduce each event obtained from a sql.Rows scan,
so that we do not have to allocate all events in a slice.
* reinstate the mutex as RWMutex
* scan data directly
* add todos
* fix(writemodels): add reduce of parent
* test: remove comment
* update comments
---------
Co-authored-by: adlerhurst <silvan.reusser@gmail.com>
This implementation increases parallel write capabilities of the eventstore.
Please have a look at the technical advisories: [05](https://zitadel.com/docs/support/advisory/a10005) and [06](https://zitadel.com/docs/support/advisory/a10006).
The implementation of eventstore.push is rewritten and stored events are migrated to a new table `eventstore.events2`.
If you are using cockroach: make sure that the database user of ZITADEL has `VIEWACTIVITY` grant. This is used to query events.
feat(storage): read only transactions for queries (#6415)
* fix: tests
* bastle wie en grosse
* fix(database): scan as callback
* fix tests
* fix merge failures
* remove as of system time
* refactor: remove unused test
* refacotr: remove unused lines
* begin init checks for projections
* first projection checks
* debug notification providers with query fixes
* more projections and first index
* more projections
* more projections
* finish projections
* fix tests (remove db name)
* create tables in setup
* fix logging / error handling
* add tenant to views
* rename tenant to instance_id
* add instance_id to all projections
* add instance_id to all queries
* correct instance_id on projections
* add instance_id to failed_events
* use separate context for instance
* implement features projection
* implement features projection
* remove unique constraint from setup when migration failed
* add error to failed setup event
* add instance_id to primary keys
* fix IAM projection
* remove old migrations folder
* fix keysFromYAML test
