Laravel Read/Write Splitting & Sticky Reads | Mohamed Said [Skip to content](#main) [ ![](https://cdn.msaied.com/01KT78WE565VEMM3PSNQAAB0MH.png) Mohamed SaidLaravel Backend Engineer ](https://www.msaied.com/public) - [Home](https://www.msaied.com/public) - [Projects](https://www.msaied.com/public/projects) - [Articles](https://www.msaied.com/public/articles) - [Certificates](https://www.msaied.com/public/certificates) - [About](https://www.msaied.com/public#about) [ Contact](https://www.msaied.com/public#contact) Menu Menu ---- Close - [HomeStart here](https://www.msaied.com/public) - [ProjectsCase studies](https://www.msaied.com/public/projects) - [ArticlesEngineering notes](https://www.msaied.com/public/articles) - [CertificatesCredentials](https://www.msaied.com/public/certificates) - [AboutHow I work](https://www.msaied.com/public#about) - [ContactGet in touch](https://www.msaied.com/public#contact) [Start a conversation](https://www.msaied.com/public#contact) [WhatsApp](https://wa.me/201094619204) [Email](mailto:hello@msaied.com) 1. [Home](https://www.msaied.com/public) 2. / 3. [Articles](https://www.msaied.com/public/articles) 4. / 5. Read/Write Splitting, Connection Pooling, and Sticky Reads in Laravel Read/Write Splitting, Connection Pooling, and Sticky Reads in Laravel ====================================================================== Learn how Laravel's database layer handles read/write splitting, when sticky reads save you from replication lag bugs, and how to pair connection pooling with PgBouncer or ProxySQL for real production throughput. ![](https://cdn.msaied.com/01M22N44A70A5MC2S599JP0MPH.webp) [Mohamed Said](https://www.msaied.com/public#person) Published 13 Aug 2026 · Updated 13 Aug 2026 · 4 min read ShareCopy linkCopied ![Read/Write Splitting, Connection Pooling, and Sticky Reads in Laravel](https://cdn.msaied.com/543/97ef3abac42d00989679f44916e2efd5.png) On this page +1. [Why Read/Write Splitting Breaks More Apps Than It Fixes](#why-readwrite-splitting-breaks-more-apps-than-it-fixes) 2. [Configuring Read/Write Connections](#configuring-readwrite-connections) 3. [The sticky Option: What It Actually Does](#the-codestickycode-option-what-it-actually-does) 4. [Forcing a Connection Explicitly](#forcing-a-connection-explicitly) 5. [Connection Pooling: PgBouncer and ProxySQL](#connection-pooling-pgbouncer-and-proxysql) 6. [Takeaways](#takeaways) Why Read/Write Splitting Breaks More Apps Than It Fixes ------------------------------------------------------- Adding a read replica feels like a free performance win. In practice, replication lag — even 50 ms — causes subtle, hard-to-reproduce bugs: a user creates a record, gets redirected, and the next page query hits the replica before the write has propagated. Laravel ships with first-class support for read/write connections, but the defaults are more dangerous than most engineers realise. --- Configuring Read/Write Connections ---------------------------------- Laravel's `config/database.php` accepts `read` and `write` keys inside any connection. The driver merges them with the top-level config, so you only override what differs: ```php 'mysql' => [ 'driver' => 'mysql', 'read' => [ 'host' => [ env('DB_READ_HOST_1', '10.0.1.11'), env('DB_READ_HOST_2', '10.0.1.12'), ], ], 'write' => [ 'host' => env('DB_WRITE_HOST', '10.0.1.10'), ], 'sticky' => true, 'database' => env('DB_DATABASE', 'app'), 'username' => env('DB_USERNAME', 'app'), 'password' => env('DB_PASSWORD', ''), 'charset' => 'utf8mb4', 'collation' => 'utf8mb4_unicode_ci', 'prefix' => '', ], ``` When multiple hosts are listed under `read`, Laravel picks one at random per request — a simple but effective load-distribution strategy. --- The `sticky` Option: What It Actually Does ------------------------------------------ With `'sticky' => true`, Laravel tracks whether a write query has been executed during the current request lifecycle. If it has, **all subsequent reads for that request are routed to the write connection**, bypassing the replica entirely. This is implemented in `Illuminate\Database\Connection` via a simple boolean flag: ```php // Simplified from the framework source if ($this->recordsHaveBeenModified() && $this->getConfig('sticky')) { return $this->getWritePdo(); } return $this->getReadPdo(); ``` The flag is reset at the start of each request via the `DatabaseServiceProvider`, so there is no cross-request leakage in FPM. Under **Laravel Octane**, however, the connection object is reused across requests — you must call `DB::resetRecordsModified()` in an `octane:request` listener or use a middleware: ```php // app/Http/Middleware/ResetDbStickyFlag.php public function handle(Request $request, Closure $next): Response { DB::connection()->resetRecordsModified(); return $next($request); } ``` Register it early in the global middleware stack. --- Forcing a Connection Explicitly ------------------------------- Sometimes you need deterministic routing regardless of sticky state — for example, an admin dashboard that must always read fresh data: ```php $users = DB::connection('mysql::write') ->table('users') ->where('active', true) ->get(); ``` Or with Eloquent: ```php User::on('mysql::write')->where('active', true)->get(); // Alternatively, use the useWritePdo() scope: User::query()->useWritePdo()->where('active', true)->get(); ``` `useWritePdo()` is available on the query builder directly and is the cleanest option for one-off overrides. --- Connection Pooling: PgBouncer and ProxySQL ------------------------------------------ Laravel opens a new PDO connection per worker process. Under FPM with 50 workers × 4 app servers, you can exhaust PostgreSQL's `max_connections` (default 100) instantly. **PgBouncer** (PostgreSQL) in `transaction` pooling mode is the standard solution. Each query borrows a server connection for its duration, then returns it to the pool. Your Laravel `DB_HOST` points to PgBouncer, not Postgres directly. Key caveats with PgBouncer transaction mode: - `SET` statements and advisory locks are **not safe** — they do not persist across queries. - Prepared statements require `server_reset_query` or disabling them in Laravel: set `'options' => [PDO::ATTR_EMULATE_PREPARES => true]` in your connection config. **ProxySQL** serves the same role for MySQL/MariaDB and additionally supports query routing rules — you can route `SELECT` statements to replicas and writes to the primary at the proxy layer, removing that concern from application config entirely. --- Takeaways --------- - Enable `sticky` on every read/write split config — replication lag bugs are silent and costly. - Under Octane, reset the modified flag explicitly; FPM handles it automatically. - Use `useWritePdo()` for admin or post-write reads that must be consistent. - Point Laravel at PgBouncer/ProxySQL rather than the database directly to avoid connection exhaustion. - Disable PDO prepared statements when using PgBouncer in transaction pooling mode. - Test replica routing in CI by asserting which connection a query targets using `DB::listen()`. - [laravel](https://www.msaied.com/public/articles?search=laravel) - [database](https://www.msaied.com/public/articles?search=database) - [postgresql](https://www.msaied.com/public/articles?search=postgresql) - [mysql](https://www.msaied.com/public/articles?search=mysql) - [performance](https://www.msaied.com/public/articles?search=performance) Frequently asked questions --------------------------- Does Laravel's sticky option work across multiple requests?No. Under PHP-FPM the sticky flag is reset at the start of each request. Under Octane, connections are reused, so you must reset it manually with DB::resetRecordsModified() in a middleware or Octane request listener. Can I use PgBouncer in transaction pooling mode with Laravel's default PDO settings?Not safely. Transaction pooling does not preserve prepared statement state between queries. Set PDO::ATTR\_EMULATE\_PREPARES to true in your connection options, or switch PgBouncer to session pooling if you need native prepared statements. When should I route reads at the proxy layer (ProxySQL) vs. in Laravel config?Proxy-layer routing is better when you have multiple applications sharing the same database cluster, or when you want to change routing rules without deploying application code. Laravel-level config is simpler for single-app setups and gives you fine-grained per-query control. ![Mohamed Said](https://cdn.msaied.com/01M22N44A70A5MC2S599JP0MPH.webp)About the author ---------------- [Mohamed Said](https://www.msaied.com/public#person)Senior Backend Engineer specializing in Laravel, scalable SaaS platforms, APIs, and cloud infrastructure. I build secure, high-performance web applications that help businesses grow. [About](https://www.msaied.com/public#about) [GitHub ↗](https://github.com/EG-Mohamed) [LinkedIn ↗](https://www.linkedin.com/in/msaiedm/) [WhatsApp ↗](https://wa.me/201094619204) [Email Address ↗](mailto:hello@msaied.com) [My CV ↗](https://drive.google.com/file/u/0/d/1MF20IPRJyzfy32mhEutjL5EpSls0w2Q8/view) [Previous articlePause All Laravel Queues During a Deploy with queue:pause --all](https://www.msaied.com/public/articles/pause-all-laravel-queues-during-a-deploy-with-queuepause-all) [Next articleEvent Sourcing in Laravel: Aggregates, Projectors, and Reactors Without the Ceremony](https://www.msaied.com/public/articles/event-sourcing-in-laravel-aggregates-projectors-and-reactors-without-the-ceremony) On this page ------------- 1. [Why Read/Write Splitting Breaks More Apps Than It Fixes](#why-readwrite-splitting-breaks-more-apps-than-it-fixes) 2. [Configuring Read/Write Connections](#configuring-readwrite-connections) 3. [The sticky Option: What It Actually Does](#the-codestickycode-option-what-it-actually-does) 4. [Forcing a Connection Explicitly](#forcing-a-connection-explicitly) 5. [Connection Pooling: PgBouncer and ProxySQL](#connection-pooling-pgbouncer-and-proxysql) 6. [Takeaways](#takeaways) ### Have a technical challenge? Tell me what you’re building. I reply within two working days. 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