From a8e02f766b93d4fcc2fed56a47a7b728b820c816 Mon Sep 17 00:00:00 2001
From: Robert Vollmert <rob@vllmrt.net>
Date: Tue, 28 Feb 2023 14:40:52 +0100
Subject: [PATCH] perf: Allow preparing pre-request SQL statement

This will prepare the pre-request statement (if prepared statements
are enabled) with a possible minor performance benefit -- the load
test is not entirely conclusive.
---
 src/PostgREST/Query.hs | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/PostgREST/Query.hs b/src/PostgREST/Query.hs
index 81842b576..a2fa37ca8 100644
--- a/src/PostgREST/Query.hs
+++ b/src/PostgREST/Query.hs
@@ -23,6 +23,8 @@ import qualified Data.Text.Encoding                as T
 import qualified Hasql.Decoders                    as HD
 import qualified Hasql.DynamicStatements.Snippet   as SQL (Snippet)
 import qualified Hasql.DynamicStatements.Statement as SQL
+import qualified Hasql.Encoders                    as HE
+import qualified Hasql.Statement                   as SQL
 import qualified Hasql.Transaction                 as SQL
 
 import qualified PostgREST.Error              as Error
@@ -268,6 +270,10 @@ setPgLocals conf claims role req actualPgVersion = lift $
 
 -- | Runs the pre-request function.
 runPreReq :: AppConfig -> DbHandler ()
-runPreReq conf = lift $ traverse_ SQL.sql preReqSql
+runPreReq conf = lift $ traverse_ (SQL.statement mempty . stmt) (configDbPreRequest conf)
   where
-    preReqSql = (\f -> "select " <> fromQi f <> "();") <$> configDbPreRequest conf
+    stmt req = SQL.Statement
+      ("select " <> fromQi req <> "()")
+      HE.noParams
+      HD.noResult
+      (configDbPreparedStatements conf)