为什么Oracle插入比Mysql快

Question

I have a little compharison between oracle 11gR2 and Mysql 5.6.

I create same schema in both DBMS with 3 tables --branch --client --loan loan has a foreign key to client, and a client has a foreign key to branch, besides all of them have primary keys.

I created branches, and client (200_000 clients) and I wanna tests insert perfomance with loan table which is consist around 50 columns.

Most of clolumns double or integer or string.

create or replace PROCEDURE create_loans( n number)
as
BEGIN
    Declare 
    i number:=0;
    randDouble float ;
    randInt number;
    randString varchar2(50);
    Begin
      while i < n 
      Loop
         randDouble := ROUND(dbms_random.value(0,1),17);
         randInt := ROUND(dbms_random.value(1,100000000));
        randString := dbms_random.string('l', 50); 

        Insert into loan_row_model.loan values(null,
            randDouble,
            randDouble*10,
            randDouble*13,
            SUBSTR(randString,1,32),
            SUBSTR(randString,2,10),
            randDouble*155,
            SUBSTR(randString,1,9),
            SUBSTR(randString,9,10),
            SUBSTR(randString,1,32),
            randDouble*6123,--annual_inc
            SUBSTR(randString,3,32),--verification_status
            SUBSTR(randString,4,30),
            randDouble,
            randInt,--open_acc
            randInt*2,
            SUBSTR(randString,7,7),
        randInt*5,--total_acc
        SUBSTR(randString,1,3),--initial_list_status
            randDouble*64,
        randDouble*4,
        randDouble*231,
        randDouble,
        randDouble,
            randDouble*12,
            randDouble,--collection_recovery_fee
            SUBSTR(randString,19,30),
            randDouble*14,--last_pymnt_amnt
            SUBSTR(randString,21,32),
            SUBSTR(randString,9,30),
            SUBSTR(randString,16,15),--policy_code
            SUBSTR(randString,1,29),--application_type
            randInt,
            randInt*7,
            randInt*4,
            randInt,
            randInt,
            randInt,
            randInt*3,
            randInt,--mths_since_rcnt_il
            randDouble*6149,
            randInt*8,--open_rv_12m
            randInt*8,--open_rv_24m
            randDouble*475,
            randDouble*37,--all_util
            randInt*4,
            randInt,
            randInt*3,
            randInt,
            randInt*9,
            TO_DATE( TRUNC( DBMS_RANDOM.VALUE(TO_CHAR(DATE '2016-01-01','J'),TO_CHAR(DATE '2046-12-31','J') )),'J'),
            ROUND(dbms_random.value(1,200000))
            );
         i := i+1;
        end loop;
    end;
END;

the procedure in mysql almost identical, I just used their native random generator for values.

Before start I have disabled parallel executing in oracle, and flush cache, in mysql also disable cache.

But as a result for 50000 inserts Oracle has 15s vs 30s in Mysql.

What is the reason, could you help?

Answer 1

MySQL can do that in 3 seconds if you "batch" 100 rows at a time. Perhaps even faster with LOAD DATA .

How often do you need to insert 50K rows? In other words, why does it matter?

Show us SHOW CREATE TABLE ; there could be various issues (favorable or unfavorable) with the indexes or lack of them, and also in the datatypes, and especially the "engine".

Were they "finished"? Both Oracle and MySQL do some variant on "delayed writes" to avoid making you wait. 15s or 30s may or may not be sustainable.

Were you using spinning drives or SSDs? RAID with write cache? What about the settings for autocommit versus BEGIN...COMMIT? Did you even do a commit? Or does the timing include a rollback?! Committing after each INSERT is not a good idea since it has a huge overhead.

Were the settings tuned optimally?

Did the table already have data? Were you inserting "at the end"? Or randomly?

When you have answered all of those, I may have another 10 questions that will show that further things can be done to make your benchmark 'prove' that one vendor or the other is faster.