Oracle SQL Forum
Can anyone tell me about PARSING in simple way?
Thanks in advance.
Any sql query runs in 3 steps. These are
In Parse time Oracle will check whether this query is already executed earlier or not? This query is new to oracle then hard parse will start .. parse will check whether the query is syntactically and symmetrically correct or not? Grammer, table names, access, grants everything will check, if everything fine, then it will create one hash value in Library cache(is a part of shared_pool_area). then it creates explain plans from there it choose one execution plan(which is less cost). then execute, then fetch will happend. (here there are 2 types of parse stages) one is soft parse and second one is hard parse. Soft parse will check whether hash value is available or not if available then simple it will execute .. if not then hard parse will start. Here Whatever I said above same process will start. if you can see the Trace file, you will understand given query executed by hard /soft parse. for example .Misses in library cache during parse: 1 .. this line will tell you .. hard parse. it is 0 then soft parse.
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