From 9f7ab1674f72d93228a7a4169c3cc809dc6679cc Mon Sep 17 00:00:00 2001 From: Gabor Szarnyas Date: Sat, 7 Sep 2024 18:02:19 +0200 Subject: [PATCH] Fix --- choke-points.tex | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/choke-points.tex b/choke-points.tex index d63cbb85..f89a4a6d 100644 --- a/choke-points.tex +++ b/choke-points.tex @@ -226,7 +226,7 @@ \section{Correlated Sub-Queries} This choke point tests the ability of the query optimizer to flatten execution plans when there are correlated sub-queries. Many queries have correlated sub-queries and their query plans can be flattened, such that the correlated sub-query is handled using an equi-join, outer-join or anti-join. -In TPC-H Q21, for instance, there is an \lstinline{EXISTS} clause (for orders with more than one supplier) and a \lstinline{NOT EXISTS} clauses (looking for an item that was received too late). +In TPC-H Q21, for instance, there is an \lstinline{EXISTS} clause (for orders with more than one supplier) and a \lstinline{NOT EXISTS} clause (looking for an item that was received too late). To execute this query well, systems need to flatten both sub-queries, the first into an equi-join plan, the second into an anti-join plan. Therefore, the execution layer of the database system will benefit from implementing these extended join variants.