snapshot of https://github.com/ThreeDotsLabs/watermill.git (master, 2026-09-15; blobs > 131072B omitted)

2026-09-15 21:27:46 +05:00
commit ce933d1277
538 changed files with 46504 additions and 0 deletions
--- a/_examples/real-world-examples/synchronizing-databases/.validate_example.yml
+++ b/_examples/real-world-examples/synchronizing-databases/.validate_example.yml
@@ -0,0 +1,4 @@
+validation_cmd: "docker compose up"
+teardown_cmd: "docker compose down"
+timeout: 180
+expected_output: "received user:"
--- a/_examples/real-world-examples/synchronizing-databases/README.md
+++ b/_examples/real-world-examples/synchronizing-databases/README.md
@@ -0,0 +1,66 @@
+# Synchronizing Databases (MySQL to PostgreSQL)
+
+This example shows how to use [SQL Pub/Sub](https://github.com/ThreeDotsLabs/watermill-sql) across two different databases.
+
+See also [SQL Pub/Sub documentation](https://watermill.io/pubsubs/sql).
+
+## Background
+
+Synchronizing two databases can be a tough task, especially with different data formats.
+This example shows how to migrate a MySQL table to PostgreSQL table using watermill.
+
+The application will first transfer all existing rows and then keep listening for any new inserts,
+copying them to the new table as soon, as they appear. Only new rows will be detected, there's no
+support for updates or deletes.
+
+The `main.go` file contains watermill-related setup, database connections and the handler translating events
+from one format to another. In `mysql.go` and `postgres.go` you will find definitions of `SchemaAdapters` for 
+each database.
+
+For more detailed description, see [When an SQL database makes a great Pub/Sub](https://threedots.tech/post/when-sql-database-makes-great-pub-sub/).
+
+## Requirements
+
+To run this example you will need Docker and docker-compose installed. See installation guide at https://docs.docker.com/compose/install/
+
+## Running
+
+Run the command and observe standard output. It should print out incoming users.
+
+```bash
+docker-compose up
+```
+
+Check what's inside MySQL by running:
+
+```
+docker-compose exec mysql mysql -e 'select * from watermill.users;'
+```
+
+```
+----+------------------+------------+-----------+---------------------+
+| id | user             | first_name | last_name | created_at          |
+----+------------------+------------+-----------+---------------------+
+|  1 | Carroll8506      | Marc       | Murphy    | 2019-09-28 13:51:53 |
+|  2 | Metz8415         | Briana     | Bauch     | 2019-09-28 13:51:54 |
+|  3 | Lebsack6887      | Tomasa     | Steuber   | 2019-09-28 13:51:55 |
+|  4 | Hauck4518        | Alexandra  | Halvorson | 2019-09-28 13:51:56 |
+|  5 | Reynolds7156     | Ariane     | Lebsack   | 2019-09-28 13:51:57 |
+----+------------------+------------+-----------+---------------------+
+```
+
+And the same for PostgreSQL:
+
+```
+docker-compose exec postgres psql -U watermill -d watermill -c 'select * from users;'
+```
+
+```
+ id  |     username     |      full_name       |     created_at
+-----+------------------+----------------------+---------------------
+   1 | Carroll8506      | Marc Murphy          | 2019-09-28 13:51:53
+   2 | Metz8415         | Briana Bauch         | 2019-09-28 13:51:54
+   3 | Lebsack6887      | Tomasa Steuber       | 2019-09-28 13:51:55
+   4 | Hauck4518        | Alexandra Halvorson  | 2019-09-28 13:51:56
+   5 | Reynolds7156     | Ariane Lebsack       | 2019-09-28 13:51:57
+```
--- a/_examples/real-world-examples/synchronizing-databases/docker-compose.yml
+++ b/_examples/real-world-examples/synchronizing-databases/docker-compose.yml
@@ -0,0 +1,31 @@
+services:
+  server:
+    image: golang:1.25
+    restart: unless-stopped
+    depends_on:
+      - mysql
+      - postgres
+    volumes:
+      - .:/app
+      - $GOPATH/pkg/mod:/go/pkg/mod
+    working_dir: /app
+    command: go run .
+
+  mysql:
+    image: mysql:8.0
+    restart: unless-stopped
+    ports:
+      - 3306:3306
+    environment:
+      MYSQL_DATABASE: watermill
+      MYSQL_ALLOW_EMPTY_PASSWORD: "yes"
+
+  postgres:
+    image: postgres:11
+    restart: unless-stopped
+    ports:
+      - 5432:5432
+    environment:
+      POSTGRES_USER: watermill
+      POSTGRES_DB: watermill
+      POSTGRES_PASSWORD: "password"
--- a/_examples/real-world-examples/synchronizing-databases/go.mod
+++ b/_examples/real-world-examples/synchronizing-databases/go.mod
@@ -0,0 +1,25 @@
+module main.go
+
+go 1.25.0
+
+require (
+	github.com/ThreeDotsLabs/watermill v1.5.1
+	github.com/ThreeDotsLabs/watermill-sql/v4 v4.1.3
+	github.com/brianvoe/gofakeit/v6 v6.28.0
+	github.com/go-sql-driver/mysql v1.10.0
+	github.com/lib/pq v1.12.3
+)
+
+require (
+	filippo.io/edwards25519 v1.2.0 // indirect
+	github.com/cenkalti/backoff/v5 v5.0.3 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
+	github.com/jackc/pgx/v5 v5.9.2 // indirect
+	github.com/lithammer/shortuuid/v3 v3.0.7 // indirect
+	github.com/oklog/ulid v1.3.1 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/sony/gobreaker v1.0.0 // indirect
+	golang.org/x/text v0.37.0 // indirect
+)
--- a/_examples/real-world-examples/synchronizing-databases/go.sum
+++ b/_examples/real-world-examples/synchronizing-databases/go.sum
@@ -0,0 +1,51 @@
+filippo.io/edwards25519 v1.2.0 h1:crnVqOiS4jqYleHd9vaKZ+HKtHfllngJIiOpNpoJsjo=
+filippo.io/edwards25519 v1.2.0/go.mod h1:xzAOLCNug/yB62zG1bQ8uziwrIqIuxhctzJT18Q77mc=
+github.com/ThreeDotsLabs/watermill v1.5.1 h1:t5xMivyf9tpmU3iozPqyrCZXHvoV1XQDfihas4sV0fY=
+github.com/ThreeDotsLabs/watermill v1.5.1/go.mod h1:Uop10dA3VeJWsSvis9qO3vbVY892LARrKAdki6WtXS4=
+github.com/ThreeDotsLabs/watermill-sql/v4 v4.1.3 h1:d9niNUM3G9nFH2YRdJ7F+qz3IF0bS2IHq6UB2TKWHGE=
+github.com/ThreeDotsLabs/watermill-sql/v4 v4.1.3/go.mod h1:Ce2GVZVnyajAh0AkwxSJXwx8ajBBveu1DI/yatan5jc=
+github.com/brianvoe/gofakeit/v6 v6.28.0 h1:Xib46XXuQfmlLS2EXRuJpqcw8St6qSZz75OUo0tgAW4=
+github.com/brianvoe/gofakeit/v6 v6.28.0/go.mod h1:Xj58BMSnFqcn/fAQeSK+/PLtC5kSb7FJIq4JyGa8vEs=
+github.com/cenkalti/backoff/v5 v5.0.3 h1:ZN+IMa753KfX5hd8vVaMixjnqRZ3y8CuJKRKj1xcsSM=
+github.com/cenkalti/backoff/v5 v5.0.3/go.mod h1:rkhZdG3JZukswDf7f0cwqPNk4K0sa+F97BxZthm/crw=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/go-sql-driver/mysql v1.10.0 h1:Q+1LV8DkHJvSYAdR83XzuhDaTykuDx0l6fkXxoWCWfw=
+github.com/go-sql-driver/mysql v1.10.0/go.mod h1:M+cqaI7+xxXGG9swrdeUIoPG3Y3KCkF0pZej+SK+nWk=
+github.com/google/uuid v1.2.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
+github.com/jackc/pgpassfile v1.0.0/go.mod h1:CEx0iS5ambNFdcRtxPj5JhEz+xB6uRky5eyVu/W2HEg=
+github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 h1:iCEnooe7UlwOQYpKFhBabPMi4aNAfoODPEFNiAnClxo=
+github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761/go.mod h1:5TJZWKEWniPve33vlWYSoGYefn3gLQRzjfDlhSJ9ZKM=
+github.com/jackc/pgx/v5 v5.9.2 h1:3ZhOzMWnR4yJ+RW1XImIPsD1aNSz4T4fyP7zlQb56hw=
+github.com/jackc/pgx/v5 v5.9.2/go.mod h1:mal1tBGAFfLHvZzaYh77YS/eC6IX9OWbRV1QIIM0Jn4=
+github.com/jackc/puddle/v2 v2.2.2 h1:PR8nw+E/1w0GLuRFSmiioY6UooMp6KJv0/61nB7icHo=
+github.com/jackc/puddle/v2 v2.2.2/go.mod h1:vriiEXHvEE654aYKXXjOvZM39qJ0q+azkZFrfEOc3H4=
+github.com/lib/pq v1.12.3 h1:tTWxr2YLKwIvK90ZXEw8GP7UFHtcbTtty8zsI+YjrfQ=
+github.com/lib/pq v1.12.3/go.mod h1:/p+8NSbOcwzAEI7wiMXFlgydTwcgTr3OSKMsD2BitpA=
+github.com/lithammer/shortuuid/v3 v3.0.7 h1:trX0KTHy4Pbwo/6ia8fscyHoGA+mf1jWbPJVuvyJQQ8=
+github.com/lithammer/shortuuid/v3 v3.0.7/go.mod h1:vMk8ke37EmiewwolSO1NLW8vP4ZaKlRuDIi8tWWmAts=
+github.com/oklog/ulid v1.3.1 h1:EGfNDEx6MqHz8B3uNV6QAib1UR2Lm97sHi3ocA6ESJ4=
+github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sony/gobreaker v1.0.0 h1:feX5fGGXSl3dYd4aHZItw+FpHLvvoaqkawKjVNiFMNQ=
+github.com/sony/gobreaker v1.0.0/go.mod h1:ZKptC7FHNvhBz7dN2LGjPVBz2sZJmc0/PkyDJOjmxWY=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
+golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
+golang.org/x/text v0.37.0 h1:Cqjiwd9eSg8e0QAkyCaQTNHFIIzWtidPahFWR83rTrc=
+golang.org/x/text v0.37.0/go.mod h1:a5sjxXGs9hsn/AJVwuElvCAo9v8QYLzvavO5z2PiM38=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
--- a/_examples/real-world-examples/synchronizing-databases/main.go
+++ b/_examples/real-world-examples/synchronizing-databases/main.go
@@ -0,0 +1,195 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	stdSQL "database/sql"
+	"encoding/gob"
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/brianvoe/gofakeit/v6"
+	driver "github.com/go-sql-driver/mysql"
+	_ "github.com/lib/pq"
+
+	"github.com/ThreeDotsLabs/watermill"
+	"github.com/ThreeDotsLabs/watermill-sql/v4/pkg/sql"
+	"github.com/ThreeDotsLabs/watermill/message"
+	"github.com/ThreeDotsLabs/watermill/message/router/middleware"
+	"github.com/ThreeDotsLabs/watermill/message/router/plugin"
+)
+
+var (
+	logger        = watermill.NewStdLogger(false, false)
+	postgresTable = "users"
+	mysqlTable    = "users"
+)
+
+func main() {
+	router, err := message.NewRouter(message.RouterConfig{}, logger)
+	if err != nil {
+		panic(err)
+	}
+
+	router.AddPlugin(plugin.SignalsHandler)
+	router.AddMiddleware(middleware.Recoverer)
+
+	mysqlDB := createMySQLConnection()
+	postgresDB := createPostgresConnection()
+
+	subscriber := createSubscriber(mysqlDB)
+	publisher := createPublisher(postgresDB)
+
+	go simulateEvents(mysqlDB)
+
+	router.AddHandler(
+		"mysql-to-postgres",
+		mysqlTable,
+		subscriber,
+		postgresTable,
+		publisher,
+		func(msg *message.Message) ([]*message.Message, error) {
+			originUser := mysqlUser{}
+
+			decoder := gob.NewDecoder(bytes.NewBuffer(msg.Payload))
+			err := decoder.Decode(&originUser)
+			if err != nil {
+				return nil, err
+			}
+
+			log.Printf("received user: %+v", originUser)
+
+			newUser := postgresUser{
+				ID:        originUser.ID,
+				Username:  originUser.User,
+				FullName:  fmt.Sprintf("%s %s", originUser.FirstName, originUser.LastName),
+				CreatedAt: originUser.CreatedAt,
+			}
+
+			var payload bytes.Buffer
+			encoder := gob.NewEncoder(&payload)
+			err = encoder.Encode(newUser)
+			if err != nil {
+				return nil, err
+			}
+
+			newMessage := message.NewMessage(watermill.NewULID(), payload.Bytes())
+
+			return []*message.Message{newMessage}, nil
+		},
+	)
+
+	if err := router.Run(context.Background()); err != nil {
+		panic(err)
+	}
+}
+
+func createMySQLConnection() *stdSQL.DB {
+	conf := driver.NewConfig()
+	conf.Net = "tcp"
+	conf.User = "root"
+	conf.Addr = "mysql"
+	conf.DBName = "watermill"
+	conf.ParseTime = true
+
+	db, err := stdSQL.Open("mysql", conf.FormatDSN())
+	if err != nil {
+		panic(err)
+	}
+
+	err = db.Ping()
+	if err != nil {
+		panic(err)
+	}
+
+	return db
+}
+
+func createPostgresConnection() *stdSQL.DB {
+	dsn := "postgres://watermill:password@postgres/watermill?sslmode=disable"
+	db, err := stdSQL.Open("postgres", dsn)
+	if err != nil {
+		panic(err)
+	}
+
+	err = db.Ping()
+	if err != nil {
+		panic(err)
+	}
+
+	return db
+}
+
+func createSubscriber(db *stdSQL.DB) message.Subscriber {
+	sub, err := sql.NewSubscriber(
+		sql.BeginnerFromStdSQL(db),
+		sql.SubscriberConfig{
+			SchemaAdapter:    mysqlSchemaAdapter{},
+			OffsetsAdapter:   sql.DefaultMySQLOffsetsAdapter{},
+			InitializeSchema: true,
+		},
+		logger,
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	return sub
+}
+
+func createPublisher(db *stdSQL.DB) message.Publisher {
+	pub, err := sql.NewPublisher(
+		sql.BeginnerFromStdSQL(db),
+		sql.PublisherConfig{
+			SchemaAdapter:        postgresSchemaAdapter{},
+			AutoInitializeSchema: true,
+		},
+		logger,
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	return pub
+}
+
+func simulateEvents(db *stdSQL.DB) {
+	pub, err := sql.NewPublisher(
+		sql.BeginnerFromStdSQL(db),
+		sql.PublisherConfig{
+			SchemaAdapter:        mysqlSchemaAdapter{},
+			AutoInitializeSchema: true,
+		},
+		logger,
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	for {
+		user := mysqlUser{
+			User:      gofakeit.Username(),
+			FirstName: gofakeit.FirstName(),
+			LastName:  gofakeit.LastName(),
+			CreatedAt: time.Now().UTC(),
+		}
+
+		var payload bytes.Buffer
+		encoder := gob.NewEncoder(&payload)
+		err := encoder.Encode(user)
+		if err != nil {
+			panic(err)
+		}
+
+		err = pub.Publish(mysqlTable, message.NewMessage(
+			watermill.NewUUID(),
+			payload.Bytes(),
+		))
+		if err != nil {
+			panic(err)
+		}
+
+		time.Sleep(time.Second)
+	}
+}
--- a/_examples/real-world-examples/synchronizing-databases/mysql.go
+++ b/_examples/real-world-examples/synchronizing-databases/mysql.go
@@ -0,0 +1,105 @@
+package main
+
+import (
+	"bytes"
+	"encoding/gob"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/ThreeDotsLabs/watermill"
+	"github.com/ThreeDotsLabs/watermill-sql/v4/pkg/sql"
+	"github.com/ThreeDotsLabs/watermill/message"
+)
+
+type mysqlUser struct {
+	ID        int64
+	User      string
+	FirstName string
+	LastName  string
+	CreatedAt time.Time
+}
+
+type mysqlSchemaAdapter struct {
+	sql.DefaultMySQLSchema
+}
+
+func (m mysqlSchemaAdapter) SchemaInitializingQueries(params sql.SchemaInitializingQueriesParams) ([]sql.Query, error) {
+	createQuery := `
+		CREATE TABLE IF NOT EXISTS ` + params.Topic + ` (
+			id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
+			user VARCHAR(36) NOT NULL,
+			first_name VARCHAR(36) NOT NULL,
+			last_name VARCHAR(36) NOT NULL,
+			created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+		);
+	`
+
+	return []sql.Query{{Query: createQuery}}, nil
+}
+
+func (m mysqlSchemaAdapter) InsertQuery(params sql.InsertQueryParams) (sql.Query, error) {
+	insertQuery := fmt.Sprintf(
+		`INSERT INTO %s (user, first_name, last_name, created_at) VALUES %s`,
+		params.Topic,
+		strings.TrimRight(strings.Repeat(`(?,?,?,?),`, len(params.Msgs)), ","),
+	)
+
+	var args []interface{}
+	for _, msg := range params.Msgs {
+		user := mysqlUser{}
+
+		decoder := gob.NewDecoder(bytes.NewBuffer(msg.Payload))
+		err := decoder.Decode(&user)
+		if err != nil {
+			return sql.Query{}, err
+		}
+
+		args = append(args, user.User, user.FirstName, user.LastName, user.CreatedAt)
+	}
+
+	return sql.Query{Query: insertQuery, Args: args}, nil
+}
+
+func (m mysqlSchemaAdapter) SelectQuery(params sql.SelectQueryParams) (sql.Query, error) {
+	nextOffsetQuery, err := params.OffsetsAdapter.NextOffsetQuery(sql.NextOffsetQueryParams{
+		Topic:         params.Topic,
+		ConsumerGroup: params.ConsumerGroup,
+	})
+	if err != nil {
+		return sql.Query{}, err
+	}
+
+	selectQuery := `
+		SELECT id, user, first_name, last_name, created_at FROM ` + params.Topic + `
+		WHERE
+			id > (` + nextOffsetQuery.Query + `)
+		ORDER BY
+			id ASC
+		LIMIT 1`
+
+	return sql.Query{Query: selectQuery, Args: nextOffsetQuery.Args}, nil
+}
+
+func (m mysqlSchemaAdapter) UnmarshalMessage(params sql.UnmarshalMessageParams) (_ sql.Row, err error) {
+	user := mysqlUser{}
+	err = params.Row.Scan(&user.ID, &user.User, &user.FirstName, &user.LastName, &user.CreatedAt)
+	if err != nil {
+		return sql.Row{}, err
+	}
+
+	var payload bytes.Buffer
+	encoder := gob.NewEncoder(&payload)
+
+	err = encoder.Encode(user)
+	if err != nil {
+		return sql.Row{}, err
+	}
+
+	msg := message.NewMessage(watermill.NewULID(), payload.Bytes())
+
+	return sql.Row{
+		Offset: user.ID,
+		Msg:    msg,
+	}, nil
+}
--- a/_examples/real-world-examples/synchronizing-databases/postgres.go
+++ b/_examples/real-world-examples/synchronizing-databases/postgres.go
@@ -0,0 +1,68 @@
+package main
+
+import (
+	"bytes"
+	"encoding/gob"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/ThreeDotsLabs/watermill-sql/v4/pkg/sql"
+)
+
+type postgresUser struct {
+	ID        int64
+	Username  string
+	FullName  string
+	CreatedAt time.Time
+}
+
+type postgresSchemaAdapter struct {
+	sql.DefaultPostgreSQLSchema
+}
+
+func (p postgresSchemaAdapter) SchemaInitializingQueries(params sql.SchemaInitializingQueriesParams) ([]sql.Query, error) {
+	createQuery := `
+		CREATE TABLE IF NOT EXISTS ` + params.Topic + ` (
+			id INT NOT NULL PRIMARY KEY,
+			username VARCHAR(36) NOT NULL,
+			full_name VARCHAR(36) NOT NULL,
+			created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+		);
+	`
+
+	return []sql.Query{{Query: createQuery}}, nil
+}
+
+func (p postgresSchemaAdapter) InsertQuery(params sql.InsertQueryParams) (sql.Query, error) {
+	insertQuery := fmt.Sprintf(
+		`INSERT INTO %s (id, username, full_name, created_at) VALUES %s`,
+		params.Topic,
+		strings.TrimRight(strings.Repeat(`($1,$2,$3,$4),`, len(params.Msgs)), ","),
+	)
+
+	var args []interface{}
+	for _, msg := range params.Msgs {
+		user := postgresUser{}
+
+		decoder := gob.NewDecoder(bytes.NewBuffer(msg.Payload))
+		err := decoder.Decode(&user)
+		if err != nil {
+			return sql.Query{}, err
+		}
+
+		args = append(args, user.ID, user.Username, user.FullName, user.CreatedAt)
+	}
+
+	return sql.Query{Query: insertQuery, Args: args}, nil
+}
+
+func (p postgresSchemaAdapter) SelectQuery(params sql.SelectQueryParams) (sql.Query, error) {
+	// No need to implement this method, as PostgreSQL subscriber is not used in this example.
+	return sql.Query{}, nil
+}
+
+func (p postgresSchemaAdapter) UnmarshalMessage(params sql.UnmarshalMessageParams) (sql.Row, error) {
+	return sql.Row{}, errors.New("not implemented")
+}