From e8d50d302c6af32185a43e1d2702f0a6b0d3b58b Mon Sep 17 00:00:00 2001
From: Robert Vollmert <rob@vllmrt.net>
Date: Fri, 3 Mar 2023 12:57:32 +0100
Subject: [PATCH] use pipeline mode

---
 postgrest.cabal        |  1 +
 src/PostgREST/Query.hs | 13 +++++++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/postgrest.cabal b/postgrest.cabal
index cc35428ceee..d1eb7f0c8b6 100644
--- a/postgrest.cabal
+++ b/postgrest.cabal
@@ -105,6 +105,7 @@ library
                     , network-uri               >= 2.6.1 && < 2.8
                     , optparse-applicative      >= 0.13 && < 0.18
                     , parsec                    >= 3.1.11 && < 3.2
+                    , postgresql-libpq
                     , protolude                 >= 0.3.1 && < 0.4
                     , regex-tdfa                >= 1.2.2 && < 1.4
                     , retry                     >= 0.7.4 && < 0.10
diff --git a/src/PostgREST/Query.hs b/src/PostgREST/Query.hs
index a18bca604ba..c8648588bb7 100644
--- a/src/PostgREST/Query.hs
+++ b/src/PostgREST/Query.hs
@@ -24,6 +24,7 @@ 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.Session                     as Session
 import qualified Hasql.Statement                   as SQL
 import qualified Hasql.Transaction                 as SQL
 
@@ -235,11 +236,19 @@ optionalRollback AppConfig{..} ApiRequest{iPreferences=Preferences{..}} = do
     shouldRollback =
       configDbTxAllowOverride && preferTransaction == Just Rollback
 
+usePipeline :: Bool
+usePipeline = True
+
+queuePipelineStatement :: params -> SQL.Statement params () -> SQL.Transaction ()
+queuePipelineStatement params stmt =
+  if usePipeline then SQL.inTransaction $ Session.queuePipelineStatement params stmt
+                 else SQL.statement params stmt
+
 -- | Runs local (transaction scoped) GUCs for every request.
 setPgLocals :: AppConfig  -> KM.KeyMap JSON.Value -> Text ->
                ApiRequest -> PgVersion -> DbHandler ()
 setPgLocals conf claims role req actualPgVersion = lift $
-  SQL.statement mempty $ SQL.dynamicallyParameterized
+  queuePipelineStatement mempty $ SQL.dynamicallyParameterized
     ("select " <> intercalateSnippet ", " (searchPathSql : roleSql ++ claimsSql ++ [methodSql, pathSql] ++ headersSql ++ cookiesSql ++ appSettingsSql))
     HD.noResult (configDbPreparedStatements conf)
   where
@@ -270,7 +279,7 @@ setPgLocals conf claims role req actualPgVersion = lift $
 
 -- | Runs the pre-request function.
 runPreReq :: AppConfig -> DbHandler ()
-runPreReq conf = lift $ traverse_ (SQL.statement mempty . stmt) (configDbPreRequest conf)
+runPreReq conf = lift $ traverse_ (queuePipelineStatement mempty . stmt) (configDbPreRequest conf)
   where
     stmt req = SQL.Statement
       ("select " <> fromQi req <> "()")