diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9fe80d63..6ebf847a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Mark schema replacements as `Stable` in sqlc templates, preventing query SQL from having to be reallocated over and over again.. [PR #1242](https://github.com/riverqueue/river/pull/1242).
 - Fix unsafe concurrent producer map access in client. [PR #1236](https://github.com/riverqueue/river/pull/1236).
 - Fix bug in `sqltemplate` cached path in order in which named args are passed to a query (previously, the order was unstable). [PR #1243](https://github.com/riverqueue/river/pull/1243).
 
diff --git a/riverdriver/riverdatabasesql/river_database_sql_driver.go b/riverdriver/riverdatabasesql/river_database_sql_driver.go
index d8a2d445..16a3ae35 100644
--- a/riverdriver/riverdatabasesql/river_database_sql_driver.go
+++ b/riverdriver/riverdatabasesql/river_database_sql_driver.go
@@ -126,7 +126,7 @@ func (e *Executor) ColumnExists(ctx context.Context, params *riverdriver.ColumnE
 		schema = "'" + params.Schema + "'"
 	}
 	ctx = sqlctemplate.WithReplacements(ctx, map[string]sqlctemplate.Replacement{
-		"schema": {Value: schema},
+		"schema": {Value: schema, Stable: true},
 	}, nil)
 
 	exists, err := dbsqlc.New().ColumnExists(ctx, e.dbtx, &dbsqlc.ColumnExistsParams{
@@ -1247,6 +1247,6 @@ func schemaTemplateParam(ctx context.Context, schema string) context.Context {
 	}
 
 	return sqlctemplate.WithReplacements(ctx, map[string]sqlctemplate.Replacement{
-		"schema": {Value: schema},
+		"schema": {Value: schema, Stable: true},
 	}, nil)
 }
diff --git a/riverdriver/riverdatabasesql/river_database_sql_driver_test.go b/riverdriver/riverdatabasesql/river_database_sql_driver_test.go
index 3097dbbf..0d23bb43 100644
--- a/riverdriver/riverdatabasesql/river_database_sql_driver_test.go
+++ b/riverdriver/riverdatabasesql/river_database_sql_driver_test.go
@@ -115,4 +115,59 @@ func TestSchemaTemplateParam(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, `SELECT 1 FROM "custom_schema".river_job`, updatedSQL)
 	})
+
+	t.Run("SchemaReplacementIsStable", func(t *testing.T) {
+		t.Parallel()
+
+		replacer, bundle := setup(t)
+
+		const sql = "SELECT 1 FROM /* TEMPLATE: schema */river_job"
+
+		updatedSQL1, _, err := replacer.RunSafely(
+			schemaTemplateParam(ctx, "my_schema"),
+			bundle.driver.ArgPlaceholder(),
+			sql,
+			nil,
+		)
+		require.NoError(t, err)
+		require.Equal(t, `SELECT 1 FROM "my_schema".river_job`, updatedSQL1)
+
+		// Second call with same SQL + same schema produces identical result.
+		// Because schema is marked Stable, the Replacer caches the output
+		// after the first call and short-circuits regex on subsequent calls.
+		updatedSQL2, _, err := replacer.RunSafely(
+			schemaTemplateParam(ctx, "my_schema"),
+			bundle.driver.ArgPlaceholder(),
+			sql,
+			nil,
+		)
+		require.NoError(t, err)
+		require.Equal(t, updatedSQL1, updatedSQL2)
+	})
+
+	t.Run("EmptySchemaReplacementIsStable", func(t *testing.T) {
+		t.Parallel()
+
+		replacer, bundle := setup(t)
+
+		const sql = "SELECT 1 FROM /* TEMPLATE: schema */river_job"
+
+		updatedSQL1, _, err := replacer.RunSafely(
+			schemaTemplateParam(ctx, ""),
+			bundle.driver.ArgPlaceholder(),
+			sql,
+			nil,
+		)
+		require.NoError(t, err)
+		require.Equal(t, "SELECT 1 FROM river_job", updatedSQL1)
+
+		updatedSQL2, _, err := replacer.RunSafely(
+			schemaTemplateParam(ctx, ""),
+			bundle.driver.ArgPlaceholder(),
+			sql,
+			nil,
+		)
+		require.NoError(t, err)
+		require.Equal(t, updatedSQL1, updatedSQL2)
+	})
 }
diff --git a/riverdriver/riverpgxv5/river_pgx_v5_driver.go b/riverdriver/riverpgxv5/river_pgx_v5_driver.go
index e0201a0e..efbddf1f 100644
--- a/riverdriver/riverpgxv5/river_pgx_v5_driver.go
+++ b/riverdriver/riverpgxv5/river_pgx_v5_driver.go
@@ -1310,6 +1310,6 @@ func schemaTemplateParam(ctx context.Context, schema string) context.Context {
 	}
 
 	return sqlctemplate.WithReplacements(ctx, map[string]sqlctemplate.Replacement{
-		"schema": {Value: schema},
+		"schema": {Value: schema, Stable: true},
 	}, nil)
 }
diff --git a/riverdriver/riverpgxv5/river_pgx_v5_driver_test.go b/riverdriver/riverpgxv5/river_pgx_v5_driver_test.go
index f89538f4..ae366d5a 100644
--- a/riverdriver/riverpgxv5/river_pgx_v5_driver_test.go
+++ b/riverdriver/riverpgxv5/river_pgx_v5_driver_test.go
@@ -238,6 +238,63 @@ func TestSchemaTemplateParam(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, `SELECT 1 FROM "custom_schema".river_job`, updatedSQL)
 	})
+
+	t.Run("SchemaReplacementIsStable", func(t *testing.T) {
+		t.Parallel()
+
+		replacer, bundle := setup(t)
+
+		const sql = "SELECT 1 FROM /* TEMPLATE: schema */river_job"
+
+		// First call
+		updatedSQL1, _, err := replacer.RunSafely(
+			schemaTemplateParam(ctx, "my_schema"),
+			bundle.driver.ArgPlaceholder(),
+			sql,
+			nil,
+		)
+		require.NoError(t, err)
+		require.Equal(t, `SELECT 1 FROM "my_schema".river_job`, updatedSQL1)
+
+		// Second call with same SQL + same schema produces identical result.
+		// Because schema is marked Stable, the Replacer caches the output
+		// after the first call and short-circuits regex on subsequent calls.
+		updatedSQL2, _, err := replacer.RunSafely(
+			schemaTemplateParam(ctx, "my_schema"),
+			bundle.driver.ArgPlaceholder(),
+			sql,
+			nil,
+		)
+		require.NoError(t, err)
+		require.Equal(t, updatedSQL1, updatedSQL2)
+	})
+
+	t.Run("EmptySchemaReplacementIsStable", func(t *testing.T) {
+		t.Parallel()
+
+		replacer, bundle := setup(t)
+
+		const sql = "SELECT 1 FROM /* TEMPLATE: schema */river_job"
+
+		updatedSQL1, _, err := replacer.RunSafely(
+			schemaTemplateParam(ctx, ""),
+			bundle.driver.ArgPlaceholder(),
+			sql,
+			nil,
+		)
+		require.NoError(t, err)
+		require.Equal(t, "SELECT 1 FROM river_job", updatedSQL1)
+
+		// Repeat — same result from cache
+		updatedSQL2, _, err := replacer.RunSafely(
+			schemaTemplateParam(ctx, ""),
+			bundle.driver.ArgPlaceholder(),
+			sql,
+			nil,
+		)
+		require.NoError(t, err)
+		require.Equal(t, updatedSQL1, updatedSQL2)
+	})
 }
 
 type nilConnDBTX struct{}
diff --git a/riverdriver/riversqlite/river_sqlite_driver.go b/riverdriver/riversqlite/river_sqlite_driver.go
index 132d0e46..b7d729ae 100644
--- a/riverdriver/riversqlite/river_sqlite_driver.go
+++ b/riverdriver/riversqlite/river_sqlite_driver.go
@@ -1680,7 +1680,7 @@ func schemaTemplateParam(ctx context.Context, schema string) context.Context {
 	}
 
 	return sqlctemplate.WithReplacements(ctx, map[string]sqlctemplate.Replacement{
-		"schema": {Value: schema},
+		"schema": {Value: schema, Stable: true},
 	}, nil)
 }
 
diff --git a/riverdriver/riversqlite/river_sqlite_driver_test.go b/riverdriver/riversqlite/river_sqlite_driver_test.go
index fcba8f36..1d445029 100644
--- a/riverdriver/riversqlite/river_sqlite_driver_test.go
+++ b/riverdriver/riversqlite/river_sqlite_driver_test.go
@@ -94,4 +94,59 @@ func TestSchemaTemplateParam(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, `SELECT 1 FROM "custom_schema".river_job`, updatedSQL)
 	})
+
+	t.Run("SchemaReplacementIsStable", func(t *testing.T) {
+		t.Parallel()
+
+		replacer, bundle := setup(t)
+
+		const sql = "SELECT 1 FROM /* TEMPLATE: schema */river_job"
+
+		updatedSQL1, _, err := replacer.RunSafely(
+			schemaTemplateParam(ctx, "my_schema"),
+			bundle.driver.ArgPlaceholder(),
+			sql,
+			nil,
+		)
+		require.NoError(t, err)
+		require.Equal(t, `SELECT 1 FROM "my_schema".river_job`, updatedSQL1)
+
+		// Second call with same SQL + same schema produces identical result.
+		// Because schema is marked Stable, the Replacer caches the output
+		// after the first call and short-circuits regex on subsequent calls.
+		updatedSQL2, _, err := replacer.RunSafely(
+			schemaTemplateParam(ctx, "my_schema"),
+			bundle.driver.ArgPlaceholder(),
+			sql,
+			nil,
+		)
+		require.NoError(t, err)
+		require.Equal(t, updatedSQL1, updatedSQL2)
+	})
+
+	t.Run("EmptySchemaReplacementIsStable", func(t *testing.T) {
+		t.Parallel()
+
+		replacer, bundle := setup(t)
+
+		const sql = "SELECT 1 FROM /* TEMPLATE: schema */river_job"
+
+		updatedSQL1, _, err := replacer.RunSafely(
+			schemaTemplateParam(ctx, ""),
+			bundle.driver.ArgPlaceholder(),
+			sql,
+			nil,
+		)
+		require.NoError(t, err)
+		require.Equal(t, "SELECT 1 FROM river_job", updatedSQL1)
+
+		updatedSQL2, _, err := replacer.RunSafely(
+			schemaTemplateParam(ctx, ""),
+			bundle.driver.ArgPlaceholder(),
+			sql,
+			nil,
+		)
+		require.NoError(t, err)
+		require.Equal(t, updatedSQL1, updatedSQL2)
+	})
 }