From 820370e06dbe4533cc0bad216fe2c0c4666dda87 Mon Sep 17 00:00:00 2001
From: Adriano Caloiaro <code@adriano.fyi>
Date: Fri, 29 Sep 2023 11:14:16 -0600
Subject: [PATCH] feat: Default to disable synchronous postgres commit

---
 backends/postgres/postgres_backend.go | 22 ++++++++++++++++++++++
 neoq.go                               |  3 ++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/backends/postgres/postgres_backend.go b/backends/postgres/postgres_backend.go
index cb1fc22..7889ea5 100644
--- a/backends/postgres/postgres_backend.go
+++ b/backends/postgres/postgres_backend.go
@@ -149,6 +149,10 @@ func Backend(ctx context.Context, opts ...neoq.ConfigOption) (pb neoq.Neoq, err
 				// there is no limit to the amount of time a worker's transactions may be idle
 				query = setIdleInTxSessionTimeout
 			}
+
+			if !p.config.SynchronousCommit {
+				query = fmt.Sprintf("%s; SET synchronous_commit = 'off';", query)
+			}
 			_, err = conn.Exec(ctx, query)
 			return
 		}
@@ -184,6 +188,24 @@ func WithTransactionTimeout(txTimeout int) neoq.ConfigOption {
 	}
 }
 
+// WithSynchronousCommit enables postgres parameter `synchronous_commit`.
+//
+// By default, neoq runs with synchronous_commit disabled.
+//
+// Postgres incurrs significant transactional overhead from synchronously committing small transactions. Because
+// neoq jobs must be enqueued individually, and payloads are generally quite small, synchronous_commit introduces
+// significant overhead, but increases data durability.
+//
+// See https://www.postgresql.org/docs/current/wal-async-commit.html for details on the implications that this has for
+// neoq jobs.
+//
+// Enabling synchronous commit results in an order of magnitude slowdown in enqueueing and processing jobs.
+func WithSynchronousCommit(enabled bool) neoq.ConfigOption {
+	return func(c *neoq.Config) {
+		c.SynchronousCommit = enabled
+	}
+}
+
 // txFromContext gets the transaction from a context, if the transaction is already set
 func txFromContext(ctx context.Context) (t pgx.Tx, err error) {
 	var ok bool
diff --git a/neoq.go b/neoq.go
index b79397c..3749506 100644
--- a/neoq.go
+++ b/neoq.go
@@ -29,13 +29,14 @@ var ErrBackendNotSpecified = errors.New("a backend must be specified")
 // per-handler basis.
 type Config struct {
 	BackendInitializer     BackendInitializer
-	BackendAuthPassword    string           // password with which to authenticate to the backend's data provider
+	BackendAuthPassword    string           // password with which to authenticate to the backend
 	BackendConcurrency     int              // total number of backend processes available to process jobs
 	ConnectionString       string           // a string containing connection details for the backend
 	JobCheckInterval       time.Duration    // the interval of time between checking for new future/retry jobs
 	FutureJobWindow        time.Duration    // time duration between current time and job.RunAfter that goroutines schedule for future jobs
 	IdleTransactionTimeout int              // the number of milliseconds PgBackend transaction may idle before the connection is killed
 	ShutdownTimeout        time.Duration    // duration to wait for jobs to finish during shutdown
+	SynchronousCommit      bool             // Postgres: Enable synchronous commits (increases durability, decreases performance)
 	LogLevel               logging.LogLevel // the log level of the default logger
 }