Hard and soft parsing parsing
All Oracle data stored in the data dictionary,
Oracle's analytic There are two hard and soft parsing parsing
Hard parse hard parse is not cached into the hard analysis
Hard analytical content: syntax error, the object exists or not, whether the user has permission to operate
hard analysis to find the optimal implementation of the program in n kinds of program implementation are consuming the most resources and time loss
soft parse soft parse There cache
SQL statement syntax
SQL object corresponding to the number of full authority does not meet the
hard and soft parsing difference is that soft resolve not need to pick the optimal solution
have to be frequently accessed data dictionary information (object authority information), so the oracle data dictionary information is placed into the share pool in with the library cache placed in a
shared pool function
shared pool cache SQL statements and SQL statement execution plan
parse parse
excel performed
fetch fetch data
shared pool composition
shared pool is a pool of memory internally into smaller blocks,
- free part of a free portion
- library cache library cache, saved a SQL statement execution plan and SQL statements
- row cache cache data dictionary information
SQL statements
The size of each memory block See
library cache
select * from v$sgastat a where a.Name='library cache
free memory
select * from v$sgastat a where a.pool='shared pool'and a.name='free memory';
row cache
select * from v$sgastat a where a.Name='row cache';
SQL
select name,value from v$sysstat where name like 'parse%';