From bf0d8bf67c56269818f739ce3219837200dc2337 Mon Sep 17 00:00:00 2001
From: David Kaufmann <astra@ionic.at>
Date: Fri, 5 Apr 2019 22:24:25 +0200
Subject: [PATCH] add exercise 1.2

---
 ex1/main_2.tex | 40 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/ex1/main_2.tex b/ex1/main_2.tex
index 8e307a9..e33af14 100644
--- a/ex1/main_2.tex
+++ b/ex1/main_2.tex
@@ -1,6 +1,44 @@
 %ex1.2
 
 \begin{enumerate}[label=(\alph*)]
-	\item empty item oida!
+	\item
+$ blockSize = 16 kB = 16384 b $ \\
+$ diskBlockSize = 64 kB = 65536 b $ \\
+$ blocksPerDiskBlock = diskBlockSize / blockSize = 4 $ \\
+$ diskSpeed = 348160 kB/s $
+\\
+$ recordsPerBlockW = math.floor(blockSize / R_{w}) = 1170 $ \\
+$ recordsPerBlockP = math.floor(blockSize / R_{p}) = 136 $ \\
+$ recordsPerBlockE = math.floor(blockSize / R_{e}) = 252 $ \\
+\\
+$ numBlocksW = math.ceil(n_{w} / recordsPerBlockW) = 48 $ \\
+$ numBlocksP = math.ceil(n_{p} / recordsPerBlockP) = 15 $ \\
+$ numBlocksE = math.ceil(n_{e} / recordsPerBlockE) = 497 $ \\
+\\
+$ tableSizeW = numBlocksW * blockSize = 768 kB $ \\
+$ tableSizeP = numBlocksP * blockSize = 240 kB $ \\
+$ tableSizeE = numBlocksE * blockSize = 7952 kB $ \\
+\\
+$ numDiskBlocksW = math.ceil(numBlocksW / blocksPerDiskBlock) = 12 $ \\
+$ numDiskBlocksP = math.ceil(numBlocksP / blocksPerDiskBlock) = 4 $ \\
+$ numDiskBlocksE = math.ceil(numBlocksE / blocksPerDiskBlock) = 125 $ \\
+\\
+$ seqScanBytesW = numDiskBlocksW * diskBlockSize = 12 * 64 kB = 768 kB $ \\
+$ seqScanBytesP = numDiskBlocksP * diskBlockSize = 4 * 64 kB = 256 kB $ \\
+$ seqScanBytesE = numDiskBlocksE * diskBlockSize = 125 * 64 kB = 8000 kB $ \\
+\\
+$ totalScanBytes = seqScanBytesW + seqScanBytesP + seqScanBytesE = 9024 kB $ \\
+\\
+$ totalTime = totalScanBytes * 1000 ms / diskSpeed = 25.919 ms $\\
+	\item
+$ indexReadBlocks = math.ceil( 18 kB / diskBlockSize ) = 1 $ \\
+$ tupleReadBlocksP = 3 $ \\
+$ totalBlocks = indexReadBlocks + tupleReadBlocksP + numDiskBlocksW + numDiskBlocksE $ \\
+$ totalBlocks = 1 + 3 + 12 + 125 = 141 $
+$ totalBytes = totalBlocks * diskBlockSize $ \\
+$ totalBytes = 141 * 64 kB = 9024 kB $ \\
+$ totalTime = totalBytes * 1000 ms / diskSpeed = 25.92 ms $ \\
+The results are the same, as the full project table can be read by reading 4 blocks.
 
+If the project table were larger, the speed would be higher.
 \end{enumerate}
-- 
2.43.0