backport #15565 (chunking into a single delete)

- a prerequisite to make order-by on delete meaningful for large transactions
digital-asset · Feb 27, 2023 · 029f2b5 · 029f2b5
1 parent 8c3cbf5
commit 029f2b5
Show file tree

Hide file tree

Showing 2 changed files with 23 additions and 13 deletions.
diff --git a/ledger-service/db-backend/BUILD.bazel b/ledger-service/db-backend/BUILD.bazel
@@ -42,6 +42,8 @@ da_scala_library(
         "//ledger/metrics",
         "//libs-scala/contextualized-logging",
         "//libs-scala/nonempty",
+        "//libs-scala/nonempty-cats",
+        "//libs-scala/scala-utils",
         "@maven//:io_dropwizard_metrics_metrics_core",
     ],
 )

diff --git a/ledger-service/db-backend/src/main/scala/com/digitalasset/http/dbbackend/Queries.scala b/ledger-service/db-backend/src/main/scala/com/digitalasset/http/dbbackend/Queries.scala
@@ -306,21 +306,25 @@ sealed abstract class Queries(tablePrefix: String, tpIdCacheMaxEntries: Long)(im
   final def deleteContracts(
       cids: Set[String]
   )(implicit log: LogHandler): ConnectionIO[Int] = {
-    import cats.data.NonEmptyVector
     import cats.instances.vector._
-    import cats.instances.int._
-    import cats.syntax.foldable._
-    NonEmptyVector.fromVector(cids.toVector) match {
-      case None =>
-        free.connection.pure(0)
-      case Some(cids) =>
-        val chunks = maxListSize.fold(Vector(cids))(size => cids.grouped(size).toVector)
-        chunks
-          .map(chunk =>
-            (fr"DELETE FROM $contractTableName WHERE " ++ Fragments
-              .in(fr"contract_id", chunk)).update.run
+    import nonempty.catsinstances._
+    cids match {
+      case NonEmpty(cids) =>
+        val del = fr"DELETE FROM $contractTableName WHERE " ++ {
+          val chunks =
+            maxListSize.fold(NonEmpty(Vector, cids)) { size =>
+              val NonEmpty(groups) =
+                cids.grouped(size).collect { case NonEmpty(group) => group }.toVector
+              groups
+            }
+          joinFragment(
+            chunks.map(cids => Fragments.in(fr"contract_id", cids.toVector.toNEF)),
+            fr" OR ",
           )
-          .foldA
+        }
+        del.update.run
+      case _ =>
+        free.connection.pure(0)
     }
   }
 
@@ -508,6 +512,10 @@ object Queries {
     case object GTEQ extends OrderOperator
   }
 
+  // XXX SC I'm pretty certain we can use NonEmpty all the way down
+  private[http] def joinFragment(xs: NonEmpty[Vector[Fragment]], sep: Fragment): Fragment =
+    concatFragment(intersperse(xs.toOneAnd, sep))
+
   private[http] def joinFragment(xs: OneAnd[Vector, Fragment], sep: Fragment): Fragment =
     concatFragment(intersperse(xs, sep))