Tkprof results

Question

hii.. i'am using tkprof to learn cost,cpu time .. of my queries.
the test_1 and test_2 tables are same exactly.
i am comparing two states. First state , i am setting arraysize to 1, then i execute "select * from test_1". then, second state, i am setting arraysize to 2500, then i execute "select * from test_2".
so, output of first state of tkprof file is written below :
===
select *
from
test_1
call count cpu elapsed disk query current rows
Parse 1 0.01 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 10006 0.70 0.72 0 10767 0 10005
total 10008 0.71 0.72 0 10767 0 10005
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: SYS
===
and second state of output of tkprof is :
===
select *
from
test_2
call count cpu elapsed disk query current rows
Parse 1 0.00 0.02 0 1 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 5 0.06 0.07 0 28 0 10005
total 7 0.06 0.09 0 29 0 10005
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: SYS
===
i understood lots of things that are related this output. but, i am confused a bit.
1-) why the "disk" column of output is zero ? Is the reason "memory is enough"?
2-) why cpu time of parsing of first output is 0.01, and second's is 0.00 ? ( why differ)
3-) what is the elapsed time exactly? and why elapsed time of firstoutput is 0 and second's is 0.02?
4-)what is the differences "query" and "current" column exactly?
thats enough for the present.
thanx for responses.

Answer 1

Did you really read the link provided to you by Stevecallan?
And you are still asking these questions.
I read
Table 20-4 SQL Trace Statistics for Parses, Executes, and Fetches.
SQL Trace Statistic Meaning
COUNT
Number of times a statement was parsed, executed, or fetched.
CPU
Total CPU time in seconds for all parse, execute, or fetch calls for the statement. This value is zero (0) if TIMED_STATISTICS is not turned on.
ELAPSED
Total elapsed time in seconds for all parse, execute, or fetch calls for the statement. This value is zero (0) if TIMED_STATISTICS is not turned on.
DISK
Total number of data blocks physically read from the datafiles on disk for all parse, execute, or fetch calls.
QUERY
Total number of buffers retrieved in consistent mode for all parse, execute, or fetch calls. Usually, buffers are retrieved in consistent mode for queries.
CURRENT
Total number of buffers retrieved in current mode. Buffers are retrieved in current mode for statements such as INSERT, UPDATE, and DELETE.
The very answers to the questions you are asking!
Are you playing games or what?
Or do you just need a dictionary to look up the meaning of the word 'elapsed'
Sybrand Bakker
Senior Oracle DBA