generate barcode vb.net SINGLE TABLE SELECTIVITY in Java

Printing Code 3 of 9 in Java SINGLE TABLE SELECTIVITY

CHAPTER 3 SINGLE TABLE SELECTIVITY
Code 39 Full ASCII Drawer In Java
Using Barcode creator for Java Control to generate, create Code 3 of 9 image in Java applications.
www.OnBarcode.com
USS Code 39 Recognizer In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Table 3-1. Small Lists of Values Can Give Big Cardinality Errors
UPC - 13 Drawer In Java
Using Barcode printer for Java Control to generate, create EAN13 image in Java applications.
www.OnBarcode.com
UCC - 12 Creation In Java
Using Barcode drawer for Java Control to generate, create UPC-A Supplement 2 image in Java applications.
www.OnBarcode.com
Size of List
Encode Barcode In Java
Using Barcode creator for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
GS1-128 Generator In Java
Using Barcode encoder for Java Control to generate, create EAN128 image in Java applications.
www.OnBarcode.com
1 2 3 4 5 6 7 8 9 10 11 12 13 14 30
Barcode Drawer In Java
Using Barcode creator for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
Leitcode Drawer In Java
Using Barcode encoder for Java Control to generate, create Leitcode image in Java applications.
www.OnBarcode.com
Cardinality 12 Values 8i (9i, 10g)
Code-39 Decoder In VS .NET
Using Barcode decoder for .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Code 3/9 Creator In Visual C#
Using Barcode encoder for .NET Control to generate, create Code 39 image in .NET applications.
www.OnBarcode.com
100 (100) 192 (200) 276 (300) 353 (400) 424 (500) 489 (600) 548 (700) 602 (800) 652 (900) 698 (1,000) 740 (1,100) 778 (1,200) 813 (1,200) 846 (1,200) 1,112 (1,200)
Code 3 Of 9 Scanner In VB.NET
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Create Linear In C#
Using Barcode creator for VS .NET Control to generate, create Linear Barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Cardinality 1,000 Values 8i (9i, 10g)
2D Barcode Drawer In Visual Basic .NET
Using Barcode generation for Visual Studio .NET Control to generate, create Matrix image in VS .NET applications.
www.OnBarcode.com
Code 128 Drawer In None
Using Barcode generation for Font Control to generate, create USS Code 128 image in Font applications.
www.OnBarcode.com
12 (12) 24 (24) 36 (36) 48 (48) 60 (60) 72 (72) 84 (84) 96 (96) 108 (108) 120 (120) 132 (132) 144 (144) 156 (156) 167 (168) 355 (360)
Barcode Reader In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
QR Code JIS X 0510 Generation In .NET
Using Barcode encoder for .NET framework Control to generate, create QR-Code image in VS .NET applications.
www.OnBarcode.com
So, there is an issue with in-lists, and this may cause problems for systems where the number of distinct values in a column is small and when you upgrade those systems, you may see execution plans changing. But, in the general case, the error in the calculations may be insignificant. Let s move on to the issue of other oddities that we might consider after seeing this one. Will the optimizer do anything unexpected with the following predicates for the table where the month_no takes only values from 1 to 12 (see oddities.sql in the online code suite)
Code 3 Of 9 Maker In .NET
Using Barcode creation for Visual Studio .NET Control to generate, create USS Code 39 image in .NET applications.
www.OnBarcode.com
Making Barcode In None
Using Barcode generation for Software Control to generate, create Barcode image in Software applications.
www.OnBarcode.com
where month_no = 25 where month_no in (4, 4) where month_no in (3, 25) where month_no in (3, 25, 26) where month_no in (3, 25, 25, 26) where month_no in (3, 25, null) where month_no in (:b1, :b2, :b3) -- outside high_value -- repeated values -- mixed set of in and out values -- ditto -- ditto with repeats -- does the optimizer spot the null -- with or without bind-variable peeking
Code39 Maker In Java
Using Barcode generator for Android Control to generate, create Code 39 image in Android applications.
www.OnBarcode.com
Barcode Creation In None
Using Barcode creator for Microsoft Word Control to generate, create Barcode image in Word applications.
www.OnBarcode.com
The results of running these tests against 8i, 9i, and 10g are shown in Table 3-2.
CHAPTER 3 SINGLE TABLE SELECTIVITY
Table 3-2. Boundary Cases with In-Lists
Predicate
month_no = 25 month_no in (4, 4) month_no in (3, 25) month_no in (3, 25, 26) month_no in (3, 25, 25, 26) month_no in (3, 25, null) month_no in (:b1, :b2, :b3)
Cardinality (8i)
100 100 192 276 276 276 276
Cardinality (9i/10g)
100 100 200 300 300 300 300 Ouch Good Ouch, but consistent Ouch, but consistent Ouch, but consistent Ouch, ouch Ouch, ouch, but consistent
So, apart from the odd double-counting factor introduced by 8i, all three versions behave the same (sometimes odd) way with in-lists. They don t notice that values are outside the high/low range, they don t notice that the list may include nulls. They do notice when you have explicit duplicates in the list but don t notice if those duplicates are hidden inside bind variables. As a final observation on in-lists, you might like to experiment with not in, using queries such as select from where ; count(*) audience month_no NOT in (1,2)
Allowing for slight rounding errors, you will find that 8i is self-consistent. The cardinality for month_no in {specific list} plus the cardinality for month_no not in {specific list} comes to 1,200 the total number of rows in the table. However, 9i and 10g are not self-consistent although the cardinality of month_no in {specific list} changes as you migrate from 8i to 9i, the mechanism for calculating month_no not in {specific list} has not. Further experimentation is left as an exercise for you to do on your own but scripts in_list_03.sql and pv.sql are available in the online code suite as a starting point for investigation. The latter includes a note on the variations that appear between versions when you start to use in-lists to create partitioned views.
PARTITIONED VIEWS DEPRECATED BUT IMPROVED
Partition views are a deprecated feature but this is one of those strange cases where the term is deprecated but the technology is not. The code that used to handle partition views is no longer special, it s just a bit of code that handles views and does it better in 10g than it ever did in Oracle 7, even when parameter _partition_view_enabled is set to false.
Copyright © OnBarcode.com . All rights reserved.