generate barcode vb.net probefrag ppasses in Java

Creation USS Code 39 in Java probefrag ppasses

probefrag ppasses
Code 39 Extended Maker In Java
Using Barcode generation for Java Control to generate, create ANSI/AIM Code 39 image in Java applications.
www.OnBarcode.com
USS Code 39 Recognizer In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Hash join one ptn
Printing Denso QR Bar Code In Java
Using Barcode maker for Java Control to generate, create QR-Code image in Java applications.
www.OnBarcode.com
Generate UPC Code In Java
Using Barcode printer for Java Control to generate, create UPC A image in Java applications.
www.OnBarcode.com
Hash join
GTIN - 128 Maker In Java
Using Barcode encoder for Java Control to generate, create UCC - 12 image in Java applications.
www.OnBarcode.com
Barcode Creation In Java
Using Barcode creation for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
Headaches
Generate USS Code 128 In Java
Using Barcode printer for Java Control to generate, create USS Code 128 image in Java applications.
www.OnBarcode.com
Draw Code 2/5 In Java
Using Barcode generation for Java Control to generate, create 2/5 Industrial image in Java applications.
www.OnBarcode.com
It is quite easy to find anomalies in the hash join calculations, and before making any comments about the differences between the various costing mechanisms, I d like to show you a couple of these anomalies so that you can appreciate the difficulty of micro-tuning the hash_area_size (or pga_aggregate_target, for that matter).
ANSI/AIM Code 39 Encoder In Java
Using Barcode printer for Android Control to generate, create USS Code 39 image in Android applications.
www.OnBarcode.com
Code 3/9 Creator In VS .NET
Using Barcode drawer for VS .NET Control to generate, create Code 3/9 image in Visual Studio .NET applications.
www.OnBarcode.com
Traditional Costing
EAN-13 Reader In VS .NET
Using Barcode scanner for .NET framework Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
QR Code Scanner In None
Using Barcode scanner for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
Go back to hash_one.sql, and run the baseline query with a manual workarea_size_policy and hash_area_size set to 1,100KB; then repeat the exercise with the hash_area_size set to 2,200KB (see script hash_one_bad.sql in the online code suite): Execution Plan (9.2.0.6 autotrace - Hash area size = 1,100 KB) -------------------------------------------------------------0 SELECT STATEMENT Optimizer=ALL_ROWS (Cost=1081 Card=2000 Bytes=4114000) 1 0 HASH JOIN (Cost=1081 Card=2000 Bytes=4114000) 2 1 TABLE ACCESS (FULL) OF 'BUILD_TAB' (Cost=255 Card=2000 Bytes=2060000) 3 1 TABLE ACCESS (FULL) OF 'PROBE_TAB' (Cost=255 Card=10000 Bytes=10270000)
Painting European Article Number 13 In Objective-C
Using Barcode generator for iPhone Control to generate, create EAN / UCC - 13 image in iPhone applications.
www.OnBarcode.com
ECC200 Maker In Java
Using Barcode generation for Android Control to generate, create DataMatrix image in Android applications.
www.OnBarcode.com
CHAPTER 12 HASH JOINS
Printing UPC Code In Java
Using Barcode generator for Android Control to generate, create UPC A image in Android applications.
www.OnBarcode.com
EAN / UCC - 14 Encoder In Visual C#.NET
Using Barcode encoder for .NET Control to generate, create GS1 128 image in Visual Studio .NET applications.
www.OnBarcode.com
Execution Plan (9.2.0.6 autotrace - Hash area size = 2,200 KB) -------------------------------------------------------------0 SELECT STATEMENT Optimizer=ALL_ROWS (Cost=2769 Card=2000 Bytes=4114000) 1 0 HASH JOIN (Cost=2769 Card=2000 Bytes=4114000) 2 1 TABLE ACCESS (FULL) OF 'BUILD_TAB' (Cost=255 Card=2000 Bytes=2060000) 3 1 TABLE ACCESS (FULL) OF 'PROBE_TAB' (Cost=255 Card=10000 Bytes=10270000) We ve increased the memory available for the hash join, and the cost of doing the hash join has gone up by a factor of 2.5. This isn t what you would expect, but it s something that happens when your memory allocation is hovering on the boundary between the optimal and onepass hash joins. The most dramatic thing about this example was that the run-time trace also showed Oracle switching, for no obvious reason, from multiblock I/O (cluster size is nine blocks) to single block I/O (cluster size is one block) when the available memory was larger. Normally, when the optimizer arithmetic does something strange, you find that the run-time mechanism does something completely different anyway. In this case, the run-time engine and the optimizer showed the same strange behavior.
Printing UPC Symbol In None
Using Barcode encoder for Online Control to generate, create UPC-A Supplement 2 image in Online applications.
www.OnBarcode.com
Barcode Generation In None
Using Barcode maker for Excel Control to generate, create Barcode image in Excel applications.
www.OnBarcode.com
Modern Costing
Generating 1D Barcode In Visual C#
Using Barcode generation for .NET framework Control to generate, create Linear image in Visual Studio .NET applications.
www.OnBarcode.com
Code 128 Printer In VB.NET
Using Barcode generator for VS .NET Control to generate, create USS Code 128 image in .NET framework applications.
www.OnBarcode.com
With the move to CPU costing and the use of dynamic workarea sizing in 9i, you may think that such anomalies are a thing of the past. Script hash_pat_bad.sql in the online code suite shows otherwise. It uses the same query as we had in hash_one.sql, enables system statistics, and uses two different values of pga_aggregate_target. Again, it is possible to produce counterintuitive results: Execution Plan (9.2.0.6 autotrace - pga_aggregate_target = 20,000 KB) ---------------------------------------------------------0 SELECT STATEMENT Optimizer=ALL_ROWS (Cost=719 Card=2000 Bytes=4114000) 1 0 HASH JOIN (Cost=951 Card=2000 Bytes=4114000) 2 1 TABLE ACCESS (FULL) OF 'BUILD_TAB' (Cost=257 Card=2000 Bytes=2060000) 3 1 TABLE ACCESS (FULL) OF 'PROBE_TAB' (Cost=257 Card=10000 Bytes=10270000) Execution Plan (9.2.0.6 autotrace - pga_aggregate_target = 22,000 KB) ---------------------------------------------------------0 SELECT STATEMENT Optimizer=ALL_ROWS (Cost=951 Card=2000 Bytes=4114000) 1 0 HASH JOIN (Cost=719 Card=2000 Bytes=4114000) 2 1 TABLE ACCESS (FULL) OF 'BUILD_TAB' (Cost=257 Card=2000 Bytes=2060000) 3 1 TABLE ACCESS (FULL) OF 'PROBE_TAB' (Cost=257 Card=10000 Bytes=10270000) The setting I have used for the pga_aggregate_target in this example is rather small even the default is larger but the test data set was also quite small. The anomaly can be re-created with larger values for the parameter by using larger data sets. The extra oddity here is that the only differences you can find in the trace files are in the 10053 trace, where the cost of doing the partition join changes. The 10104 trace files are identical. This is another indication that the optimizer and the run-time engine don t always use the same model.
CHAPTER 12 HASH JOINS
Comparisons
Oddities exist in the costing particularly in the boundary areas where the memory is in the right ballpark for the switch between one level of join and the next. There are contradictions between the model used by the optimizer code and the activity carried out by the run-time engine. However, it is possible to get a rough idea of what s going on, and make some guesses about how data sizes and parameter settings make a difference. And with the aid of the 10053 and 10104 traces, it is possible to work out whether you can do some tweaking to make an important query operate more efficiently. At present, though, I don t think that this micromanagement viewpoint is terribly important. The real issue that most people have to face is the impact of migrating between versions of Oracle, and deciding which features to enable. This is where problems are likely to occur. So in this section, we will run a standardized test so that we can compare the behavior of the optimizer in four different working environments. The online code suite contains four scripts to help us compare the different behaviors. Between them, they cover four separate combinations of options:
CPU costing disabled, manual hash_area_size allocation CPU costing enabled, manual hash_area_size allocation CPU costing disabled, automatic hash_area_size allocation CPU costing enabled, automatic hash_area_size allocation has_nocpu_harness.sql has_cpu_harness.sql pat_nocpu_harness.sql pat_cpu_harness.sql
Of these, the first is the traditional 8i approach, the last is where I think your strategic choice ought to be with 9i. Unfortunately, the results you get from hash join calculations vary dramatically with your choice.
Copyright © OnBarcode.com . All rights reserved.