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Now, let's take the conceptual model to a much more realistic level to clarify the library cache object relationships. Three figures are involved in this example. Figure 7-4 is the actual shell script containing the SQL. I simply copied and pasted the code into my Oracle user Linux session. Figure 7-5 is a library cache model with the actual real-life object references. Figure 7-6 shows the relevant parts extracted from the actual trace file.
Figure 7-4. Shown are a few lines of code, which show library cache object relationships. Figure 7-5 is a model of the library cache objects, and Figure 7-6 shows the key parts from the actual trace file.
Figure 7-4 starts with simply connecting to Oracle. To ensure I didn't lose any critical trace file pieces, I set my dump file size to unlimited. I then created a very simple table, named findme, to make it easy to find the SQL in the massive trace file. Just as I did in Figure 7-1, I executed the same SQL statement but altered an optimizer parameter. This should result in two child cursors. Then I executed a different SQL statement, which references the same findme table. I did this to show that different SQL statements will reference the same table handle. Finally, I performed the library cache dump and disconnected.
©2009, 2010 by Craig Shallahamer. This is copyrighted material.
PleaseOut of respect for those involved in the creation of the book and also for
their familes, we ask you to respect the copyright both in intent and deed. Thank you.
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