Top 5 Timed Foreground Events - Library Cache Lock & Library Cache Pin

 Library Cache Lock & Library Cache Pin


Library cache lock will be obtained on database objects referenced during parsing or compiling of SQL or PL/SQL statements (table, view, procedure, function, package, package body, trigger, index, cluster, and synonym). The lock will be released at the end of the parse or compilation.

I am not discussing more on the theory part of the this wait event as I have discussed more about them in my previous blog. You can find the much detailed explanation of possible reasons and solutions with the below link

 http://orakhoj.blogspot.com/2011/10/top-5-timed-foreground-events-library_17.html

Here I am just discussing about the recent issue we faced in our load test environment. When we ran the load with X amount of SGA we see DB Time increased to very high value and found Library Cache Lock and Library Cache Pin as TOP 2 Wait events.

Solutions: We just increased the SGA to Y amount and re ran the same load which has given wonderful results. The DB time has reduced to a considerable amount and Library Cache Lock has disappeared from the TOP wait event. So the solutions which I discussed in the above link, here it are the practical implementation.  The increase in Shared Pool via increasing the SGA has solved the problem to get rid of this wait event.