perf: use LATERAL instead of CTE for json body

* add pgbench test for INSERT and RPC
* use LATERAL for RPC and INSERT
* add tests for inlining

test/spec/Feature/Query/PlanSpec.hs

@@ -8,7 +8,9 @@ import Network.Wai.Test (SResponse (..))
 
 import           Data.Aeson.Lens
 import           Data.Aeson.QQ
+import qualified Data.ByteString      as BS
 import qualified Data.ByteString.Lazy as LBS
+import qualified Data.Text            as T
 import           Network.HTTP.Types
 import           Test.Hspec           hiding (pendingWith)
 import           Test.Hspec.Wai
@@ -166,10 +168,7 @@ spec actualPgVersion = do
       liftIO $ do
         resHeaders `shouldSatisfy` elem ("Content-Type", "application/vnd.pgrst.plan+json; charset=utf-8")
         resStatus `shouldBe` Status { statusCode = 200, statusMessage="OK" }
-        totalCost `shouldBe`
-          if actualPgVersion > pgVersion120
-            then 3.28
-            else 3.33
+        totalCost `shouldBe` 3.27
 
     it "outputs the total cost for an update" $ do
       r <- request methodPatch "/projects?id=eq.3"
@@ -182,10 +181,7 @@ spec actualPgVersion = do
       liftIO $ do
         resHeaders `shouldSatisfy` elem ("Content-Type", "application/vnd.pgrst.plan+json; charset=utf-8")
         resStatus `shouldBe` Status { statusCode = 200, statusMessage="OK" }
-        totalCost `shouldBe`
-          if actualPgVersion > pgVersion120
-            then 12.45
-            else 12.5
+        totalCost `shouldBe` 12.45
 
     it "outputs the total cost for a delete" $ do
       r <- request methodDelete "/projects?id=in.(1,2,3)"
@@ -212,10 +208,7 @@ spec actualPgVersion = do
       liftIO $ do
         resHeaders `shouldSatisfy` elem ("Content-Type", "application/vnd.pgrst.plan+json; charset=utf-8")
         resStatus `shouldBe` Status { statusCode = 200, statusMessage="OK" }
-        totalCost `shouldBe`
-          if actualPgVersion >= pgVersion120
-            then 1.3
-            else 1.35
+        totalCost `shouldBe` 1.29
 
     it "outputs the plan for application/vnd.pgrst.object" $ do
       r <- request methodDelete "/projects?id=eq.6"
@@ -338,7 +331,7 @@ spec actualPgVersion = do
       r <- request methodGet "/rpc/get_projects_below?id=3"
              [planHdr] ""
 
-      liftIO $ planCost r `shouldSatisfy` (< 36.4)
+      liftIO $ planCost r `shouldSatisfy` (< 45.4)
 
     it "should not exceed cost when calling setof composite proc with empty params" $ do
       r <- request methodGet "/rpc/getallprojects"
@@ -367,6 +360,29 @@ spec actualPgVersion = do
 
         liftIO $ planCost r `shouldSatisfy` (< 5.85)
 
+    context "function inlining" $ do
+      it "should inline a zero argument function" $ do
+        r <- request methodGet "/rpc/getallusers?id=eq.1"
+               [(hAccept, "application/vnd.pgrst.plan")] ""
+
+        let resBody = simpleBody r
+
+        liftIO $ do
+          resBody `shouldSatisfy` (
+            if actualPgVersion >= pgVersion120
+              then (\t -> T.isInfixOf "Index Scan using users_pkey on users" (decodeUtf8 $ BS.toStrict t))
+              else (\t -> T.isInfixOf "Seq Scan on users" (decodeUtf8 $ BS.toStrict t)))
+
+      it "should inline a function with arguments" $ do
+        r <- request methodGet "/rpc/getitemrange?min=10&max=15"
+               [(hAccept, "application/vnd.pgrst.plan")] ""
+
+        let resBody = simpleBody r
+
+        liftIO $ do
+          -- a Seq Scan ensures the function is inlined as the plan uses the underlying table
+          resBody `shouldSatisfy` (\t -> T.isInfixOf "Seq Scan on items" (decodeUtf8 $ BS.toStrict t))
+
 disabledSpec :: SpecWith ((), Application)
 disabledSpec =
   it "doesn't work if db-plan-enabled=false(the default)" $ do