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The ClickHouse analytics schema for Yii3 A/B testing. It owns the schema v2 tables that both delivery paths write into, ships their migrations, and gives producers a column contract to check against. It does not write events.

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Documentation site: rasuvaeff.github.io/yii3-ab-testing covers the whole family — including the integration matrix for assembling a combination.

Requirements

PHP 8.3+
rasuvaeff/yii3-ab-testing ^2.0
rasuvaeff/clickhouse-toolkit ^1.6 and simpod/clickhouse-client ^0.8 (with a PSR-18 HTTP client, for example guzzlehttp/guzzle) to apply the schema

Installation

composer require rasuvaeff/yii3-ab-testing-clickhouse

Upgrading from 1.x? See UPGRADE.md — the direct writers are gone.

How events get here

This package has no tracker. Events arrive through one of two paths, and both produce the same rows:

Path	Install	Trade-off
Durable	`yii3-ab-testing-outbox` + `yii3-outbox-db` + a worker (`outbox:clickhouse:export`)	survives an analytics outage; needs a table and a running worker
Log shipping	core's `LoggerExposureTracker` / `LoggerConversionTracker` + Vector / Fluent Bit	no worker, no request-time network call; delivery is the collector's job

Never insert from the request path. Under PHP-FPM that is a synchronous insert of a few rows per request, inside the visitor's latency — the reason the direct writer was removed in 2.0.

config/di.php binds nothing, so installing this package next to any tracker adapter cannot cause a yiisoft/config Duplicate key error.

Database schema

Table	Constant	Rows
`ab_exposures_v2`	`AnalyticsSchemaV2::EXPOSURES_TABLE`	one per exposure event
`ab_conversions_v2`	`AnalyticsSchemaV2::CONVERSIONS_TABLE`	one per conversion, adds `goal` and `exposure_event_id`

CREATE TABLE ab_exposures_v2
(
    event_id            String,
    occurred_at         DateTime64(3, 'UTC'),
    ingested_at         DateTime('UTC') DEFAULT now(),
    experiment          LowCardinality(String),
    variant             LowCardinality(String),
    subject_id          String,
    decision_reason     LowCardinality(String),
    assignment_source   LowCardinality(String),
    experiment_revision LowCardinality(String) DEFAULT '',
    environment         LowCardinality(String) DEFAULT '',
    dimensions          String DEFAULT '{}'
)
ENGINE = ReplacingMergeTree(ingested_at)
PARTITION BY toYYYYMM(occurred_at)
ORDER BY (experiment, event_id)

event_id is minted once by the core and is the deduplication key of the whole pipeline: a delivery retried after an uncertain outcome carries the same value.
occurred_at is event time, not delivery time. It drives the partition key, so a retry crossing a month boundary still lands in the same partition and collapses.
ingested_at is filled by the table and must not be supplied by a producer.
dimensions is a JSON string, not a Map: the outbox exporter rejects nested payload fields, and both delivery paths must produce identical rows. Read it with JSONExtract(dimensions, 'Map(String, String)').

Column contract

use Rasuvaeff\Yii3AbTestingClickHouse\AnalyticsSchemaV2;

AnalyticsSchemaV2::EXPOSURE_COLUMNS;   // ordered insert columns
AnalyticsSchemaV2::CONVERSION_COLUMNS; // the same plus goal and exposure_event_id

Column order is part of the contract: an INSERT lists columns positionally, so a producer that reorders them writes a variant into the subject column without any error. yii3-ab-testing-outbox routes into these constants rather than restating them, and a test pins them to the shipped DDL.

Applying migrations

use Rasuvaeff\Yii3AbTestingClickHouse\SchemaMigrations;

$applied = (new SchemaMigrations(client: $clickHouseClient, logger: $logger))->apply();
// list of applied migration names; a second call returns []

apply() runs the shipped migrations/*.sql through clickhouse-toolkit's ClickHouseMigrationRunner, resolved from the package itself rather than a hardcoded vendor/ path. Applying is explicit, never automatic: creating analytics tables is a deployment step.

Custom table names go to apply('exp_v2', 'conv_v2'). An application that runs its own migration pipeline — for example rasuvaeff/yii3-clickhouse-toolkit — takes the directory and the exact token map from the package:

use Rasuvaeff\Yii3AbTestingClickHouse\SchemaMigrations;

SchemaMigrations::path();          // directory of the shipped .sql files
SchemaMigrations::placeholders();  // ['exposures_table' => …, 'exposures_table_v2' => …, …]

Renaming after the first apply. The runner's checksum covers the resolved SQL, so changing a name once a migration has been applied is reported as a divergence instead of silently creating a second table.

Schema v1 tables

The v1 tables ab_exposures / ab_conversions are still created, so an installation upgraded from 1.x keeps reading its history. They are not migrated into v2 and are not comparable row for row: v1 rows have no event identity, and their ts is ingestion time.

Retention

Opt-in TTL templates live in retention/. They are deliberately not migrations: installing or upgrading the package must never start deleting analytics data. The shipped templates target the v1 tables ({{exposures_table}} / {{conversions_table}}, column ts); resolve them and a positive integer {{retention_days}}, review the SQL, then apply it through your deployment process. The matching disable_*_ttl.sql templates remove the policy without dropping rows. For the v2 tables write the equivalent MODIFY TTL on occurred_at.

Reading results

SELECT variant, uniqExact(subject_id) AS subjects
FROM ab_exposures_v2 FINAL
WHERE experiment = 'checkout_button'
  AND decision_reason = 'assigned'
GROUP BY variant

FINAL (or GROUP BY event_id with argMax). ReplacingMergeTree collapses duplicates on merge only, and delivery is at-least-once, so a plain count over-counts after any retry. AnalyticsSchemaV2::DEDUPLICATION_NOTE states the rule.
decision_reason = 'assigned'. Forced (QA) traffic and both kinds of fallback are recorded but are not experiment participation.

API reference

Class	Description
`AnalyticsSchemaV2`	Table names and ordered insert columns of schema v2 — the contract producers check against, pinned to the shipped DDL
`SchemaMigrations`	Applies the shipped `.sql` files; exposes their path and placeholder map

Security

Credentials travel through clickhouse-toolkit's client configuration (headers / env), never in URLs.
subject_id is stored verbatim and may be personally identifiable. Apply a retention policy that matches your privacy obligations.

Examples

See examples/ for a runnable script (no server required) that prints the column contract and the query shape a reader must use.

Development

composer build          # full gate: validate + normalize + cs + psalm + test
composer cs:fix         # auto-fix code style
composer psalm          # static analysis
composer test           # run unit tests (integration tests skipped without CLICKHOUSE_HOST)
vendor/bin/testo --suite=Integration # requires CLICKHOUSE_HOST; runs live in CI

License

BSD-3-Clause. See LICENSE.md.

rasuvaeff / yii3-ab-testing-clickhouse

Package info

Security

Statistics

README

Requirements

Installation

How events get here

Database schema

Column contract

Applying migrations

Schema v1 tables

Retention

Reading results

API reference

Security

Examples

Development

License