Re: Do you use ASSM (Automatic Segment Space Management)?
Date: Tue, 4 Aug 2009 21:32:35 -0700 (PDT)
Message-ID: <f57e0831-0b4f-4708-872e-9db2360053d2_at_d4g2000prc.googlegroups.com>
On Aug 4, 5:43 pm, ca111026 <ca111..._at_gmail.com> wrote:
> Would you be able to do a simple test? Create average-size table in
> ASSM tablespace, let's say 1,000,000 rows with
> row size approx 100 bytes. Then insert additional 10,000 rows into the
> table using singe-row insert, record how long it takes.
> Then delete all rows from the table, don't commit.
> Then repeat insert of 10,000 rows from another session. Check how long
> it takes.
>
> In my tests second insert takes much, much longer - an hour instead of
> several seconds.
Something is definitely different in your system.
Here are my results:
SQL> select count(1) from zot;
COUNT(1)
1339456
Elapsed: 00:00:00.24
SQL> desc zot;
Name Null? Type ----------------------------------------- -------- ---------------------------- OWNER NOT NULL VARCHAR2(30) TABLE_NAME NOT NULL VARCHAR2(30) COLUMN_NAME NOT NULL VARCHAR2(30) DATA_TYPE VARCHAR2(106) DATA_TYPE_MOD VARCHAR2(3) DATA_TYPE_OWNER VARCHAR2(30) DATA_LENGTH NOT NULL NUMBER DATA_PRECISION NUMBER DATA_SCALE NUMBER NULLABLE VARCHAR2(1) COLUMN_ID NUMBER DEFAULT_LENGTH NUMBER NUM_DISTINCT NUMBER LOW_VALUE RAW(32) HIGH_VALUE RAW(32) DENSITY NUMBER NUM_NULLS NUMBER NUM_BUCKETS NUMBER LAST_ANALYZED DATE SAMPLE_SIZE NUMBER CHARACTER_SET_NAME VARCHAR2(44) CHAR_COL_DECL_LENGTH NUMBER GLOBAL_STATS VARCHAR2(3) USER_STATS VARCHAR2(3) AVG_COL_LEN NUMBER CHAR_LENGTH NUMBER CHAR_USED VARCHAR2(1) V80_FMT_IMAGE VARCHAR2(3) DATA_UPGRADED VARCHAR2(3) HISTOGRAM VARCHAR2(15)
(came from dba_tab_columns. zot1 is a subset)
SQL> insert into zot select * from zot1;
13214 rows created.
Elapsed: 00:00:00.21
SQL> delete from zot;
1352670 rows deleted.
Elapsed: 00:01:45.35
SQL> insert into zot select * from zot1;
13214 rows created.
Elapsed: 00:00:00.08
SQL> commit;
Commit complete.
Elapsed: 00:00:00.06
SQL> select count(1) from zot;
COUNT(1)
13214
Elapsed: 00:00:00.14
In simple terms: bugger all difference between first insert and second
insert.
If anything, second was faster.
Received on Tue Aug 04 2009 - 23:32:35 CDT