From 050d14cab767888d4040c59927f12dc4fa2609c2 Mon Sep 17 00:00:00 2001
From: David Kaufmann <astra@ionic.at>
Date: Sun, 7 Apr 2019 23:21:55 +0200
Subject: [PATCH] layoutstuff

---
 ex1/main_5.tex | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/ex1/main_5.tex b/ex1/main_5.tex
index a2107ce..ab0e748 100644
--- a/ex1/main_5.tex
+++ b/ex1/main_5.tex
@@ -6,12 +6,14 @@
 Optimized query:
 \begin{verbatim}
 SELECT distinct(displayname) FROM posts p
-    JOIN users u ON u.id = p.owneruserid
+    JOIN users u ON p.owneruserid = u.id
     WHERE p.viewcount > u.views;
 \end{verbatim}
 
 Improvements:\\
-Just converted the selection to a JOIN
+Just converted the selection to a JOIN.
+This improves the $n_{users} + n_{users} * n_{posts}$ Seq Scans
+to one JOIN and two Seq Scans.
 
 Original version:
 \begin{verbatim}
@@ -32,6 +34,9 @@ Optimized query:
 SELECT score FROM comments WHERE text ILIKE 'yes%';
 \end{verbatim}
 
+Improvements:\\
+None so far.
+
 Original version:
 \begin{verbatim}
  Planning time: 0.540 ms
@@ -53,7 +58,8 @@ SELECT DISTINCT postid FROM votes WHERE postid NOT IN (
 \end{verbatim}
 
 Improvements:\\
-Instead of doing about twelve million Seq Scans this is now reduces it to two Seq Scans by inverting the condition.
+Instead of doing about twelve million Seq Scans this is now reduced to
+two Seq Scans by inverting the condition.
 
 Original version:
 \begin{verbatim}
@@ -84,6 +90,9 @@ SELECT p.*, c.*, u.* FROM posts p
         ) AND b.name IN ('Autobiographer','Supporter');
 \end{verbatim}
 
+Improvements:\\
+Converted the joins via WHERE clause to proper JOINs
+
 Original version:
 \begin{verbatim}
  Planning time: 4.084 ms
-- 
2.43.0