I am creating a table where ID is an integer and the where clause will always be in range(for e.g between 200 and 400).
for best performance which index can i create on table such that query runs faster ?(a)clustered(b)non-clustered(c)unique(d)both clustered and non clustered
Is it possible within a CASE statement to put conditions on the date range that I want to pull? IE: am versus pm. The query has to pull specific time ranges for an AM run versus a PM run.
.....
FROM
table
WHERE
CASE
WHEN TO_CHAR(SYSDATE,'AM') = 'AM'
THEN table.date BETWEEN TRUNC(SYSDATE) AND SYSDATE
ELSE table.date BETWEEN TRUNC(SYSDATE+12/24) AND SYSDATE
Let's consider such table that all rows fit into single block:
SQL> create table test as select rownum id, '$'||rownum name from dual connect by level <= 530;
Table created.
SQL> create index i_test on test(id);
Index created.
SQL>
SQL> begin
[code].....
why does approach with full scan take longer even if table occupies only one data block? PS. 11gR2
How can i force a sql use index range scan?
View 10 Replies View RelatedI have a query that seems to repeatedly call an index scan on a table for reasons I'm not sure about. Why it would be doing the index scan on totaldwellingarea in the dimensions table (DIMEN_PID_TDWELLAREA) repeatedly? This only seems to happen when I put on the range clause d.totaldwellingarea between scr.lowvalue and scr.highvalue.
I am using Oracle version 9.2.0.3.
select d.propertyid,d.totaldwellingarea, e.size_, scr.size_
from eqid e, dimensions d, brt_eval.size_code_ranges scr
where e.style not in ('1','A','G','L') and e.size_ = '0'
and d.propertyid = e.propertyid and e.style = scr.style and d.totaldwellingarea between scr.lowvalue and scr.highvalue;
CREATE
TABLE "BRT_ADMIN"."EQID"
(
"PROPERTYID" VARCHAR2(20 BYTE) NOT NULL ENABLE,
"EQID" CHAR(10 BYTE),
"ZONE_" CHAR(1 BYTE),
"AREA" CHAR(1 BYTE),
[code].....
I have, it would appear, successfully installed APEX 4.2 & APEX Listener 2.0 EA (in WebLogic). APEX works fine and it's reverse proxied using mod_weblogic through the OHS. I have configured APEX Printing to be via the APEX Listener.
However, creating a simple report, enabling printing, running the report (e.g. PDF or Word) produces the following few-byte content (only) inside the actual PDF file (obviously not in PDF format):
String index out of range: -1
Furthermore, it throws the exception below on the WebLogic console.
Any experience with the APEX Listener - and if so managed to rectify it?
SEVERE: String index out of range: -1
java.lang.StringIndexOutOfBoundsException: String index out of range: -1
at java.lang.String.substring(String.java:1931)
at oracle.dbtools.apex.hooks.postProcess.FOP2PDF.requestTOPDF(FOP2PDF.java:82)
at oracle.dbtools.apex.hooks.postProcess.FOP2PDF.postProcess(FOP2PDF.java:36)
[Code]...
In the link below [URL] Thomas kyte has said, use the CBO and select /*+ FIRST_ROWS */ primary_key from table where rownum = 1; it'll read the index and stop at the first row. very fast on a big empty table (as the index is small and empty).
very fast on a big full table as the index is just read to find the first leaf node and then "stop".
It gives faster result if the primary key is used. But what if we have a table with around 1000 million rows and for the predicates there is a index range scan on the table.
What if we have a table say big_table (10000000000 rows) and the sql is something like
select /*+ first_rows */ 1 /* id, attribute_id*/
from big_table
where attribute_name ='Gross Premium'
and value ='10000'
and version_date is null
and rownum=1; --it's taking around 3 min
We observed that in such case there will be a range index scan for the index on the predicates. For a particular id there may be different values for attribute 'Gross Premium' and may have multiple versions.
How I would tune such a query where the purpose is to check if at least 1 records exists in the table for the input?
I created table Rang pertitionned, and List subpartitionned. My table is Interval partitionning. My subpartition is template based as is :
PARTITION BY RANGE ( DINFOIDENTITE )
INTERVAL ( (NUMTOYMINTERVAL(1,'MONTH')) )
SUBPARTITION BY LIST ( AVANT_DERNIER_MATCLE )
[Code]....
i would have the same repartition with 10 differents tablespaces, one for each subpartition.
I search on Oracle documentation this morning, but the only thing i've found is that this option is possible with the STORE IN clause, but only for HASH partitionning.
Is there a way to specify STORAGE clause with a template for my indexes ?
My understanding of DB_FILE_MULTIBLOCK_READ_COUNT parameter is that it affects only Full Table Scans and Fast Full Index Scans - all other disk retrieval is single block.If so, then maybe I'm reading this trace incorrectly:
select /*+ first_rows */ pk
from test_join_tgt
where pk >= 0
and rownum > 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 1 21.48 27.77 22368 22134 0 0
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 3 21.49 27.78 22368 22134 0 0
[code]...
What the heck is going on with the Multi-block reads in the Range Scan?
I have created domain indexes on text columns of a materialised view to use "contains" clause when searching for data. The select query with "contains" clause does not return any records, however I was able to retrive data using via regular query using a like search.
-> will exec ctx_ddl.sync_index('index_name')'resolve my problem?
-> since the view is a materialized view, how can i make sure that the latest data added are also picked up?
I came across situation where a Nullable column is not using index for 'order by' clause. I added Not Null condition in the 'where' condition but it wasn't useful. I don't wanted to make composite index with not nullable column or with constant or modify column to 'Not Null'
So I carried out test cases and during which I found that in one case the sql statement does 'fast full scan' for data access but does not use index for 'order by' sorting
here are the steps
Initially I kept the column Nullable
SQL> create sequence s5;
Sequence created.
SQL> create table t5 as select s5.nextval id,a.* from dba_objects a where rownum<1001;
Table created.
SQL> set pages 100
SQL> select column_name,nullable from user_tab_columns where table_name='T5';
SQL> create index i5 on t5(id);
Index created.
SQL> exec dbms_stats.gather_table_stats(user,'T5',cascade=>true);
PL/SQL procedure successfully completed.
exit
SQL> alter session set events '10046 trace name context forever, level 12';
select *
from
t5 where id is not null order by id
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 68 0.00 0.00 0 16 0 1000
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 70 0.01 0.00 0 16 0 1000
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 5
Rows Row Source Operation
------- ---------------------------------------------------
1000 SORT ORDER BY (cr=16 pr=0 pw=0 time=4771 us)
1000 TABLE ACCESS FULL T5 (cr=16 pr=0 pw=0 time=1157 us)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 68 0.00 0.00
SQL*Net message from client 68 49.49 49.72
********************************************************************************
select /*+ index(t i5) */ *
from
t5 t where id is not null order by id
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 68 0.00 0.00 0 150 0 1000
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 70 0.00 0.00 0 150 0 1000
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 5
Rows Row Source Operation
------- ---------------------------------------------------
1000 TABLE ACCESS BY INDEX ROWID T5 (cr=150 pr=0 pw=0 time=5167 us)
1000 INDEX FULL SCAN I5 (cr=71 pr=0 pw=0 time=3141 us)(object id 4673065)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 69 0.00 0.00
SQL*Net message from client 69 22.89 28.04
Now I modified the 'id' column to Not Null
SQL> alter table t5 modify id not null;
SQL> set pages 100
SQL> select column_name,nullable from user_tab_columns where table_name='T5';
COLUMN_NAME N
------------------------------ -
ID N
OWNER Y
OBJECT_NAME Y
SUBOBJECT_NAME Y
OBJECT_ID Y
DATA_OBJECT_ID Y
OBJECT_TYPE Y
CREATED Y
LAST_DDL_TIME Y
TIMESTAMP Y
STATUS Y
TEMPORARY Y
GENERATED Y
SECONDARY Y
14 rows selected.
select *
from
t5 order by id
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.01 0 29 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 68 0.00 0.00 0 16 0 1000
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 70 0.01 0.01 0 45 0 1000
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 5
Rows Row Source Operation
------- ---------------------------------------------------
1000 SORT ORDER BY (cr=16 pr=0 pw=0 time=2398 us)
1000 TABLE ACCESS FULL T5 (cr=16 pr=0 pw=0 time=1152 us)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 68 0.00 0.00
SQL*Net message from client 68 37.74 37.91
********************************************************************************
select /*+ index(t i5) */ *
from
t5 t order by id
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 68 0.00 0.00 0 150 0 1000
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 70 0.00 0.00 0 150 0 1000
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 5
Rows Row Source Operation
------- ---------------------------------------------------
1000 TABLE ACCESS BY INDEX ROWID T5 (cr=150 pr=0 pw=0 time=4166 us)
1000 INDEX FULL SCAN I5 (cr=71 pr=0 pw=0 time=3142 us)(object id 4673065)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 68 0.00 0.00
SQL*Net message from client 68 8.28 8.45
select id
from
t5 order by id
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 68 0.00 0.00 0 6 0 1000
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 70 0.00 0.00 0 6 0 1000
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 5
Rows Row Source Operation
------- ---------------------------------------------------
1000 SORT ORDER BY (cr=6 pr=0 pw=0 time=1342 us)
1000 INDEX FAST FULL SCAN I5 (cr=6 pr=0 pw=0 time=1093 us)(object id 4673065)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 68 0.00 0.00
SQL*Net message from client 68 1.88 1.89
Questions are
1) Why adding 'where id is not null wasn't enough for the index to get used in 'order by'?
2) While we got 'fast full scan' why index wasn't used for 'order by' clause?
3) Do we need the indexed column in where clause for being used in 'order by clause' too?
4) Do we need 'order by' clause if we are selecting only the indexed column with sequence generated values?
I am running a fairly busy Oracle 10gR2 DB, one of the tables has about 120 columns and this table receives on average 1500 insertions per second. The table is partitioned and the partitioning is based on the most important of the two timestamp columns. There are two timestamps, they hold different times.
Out of these 120 columns, about 15 need to be indexed. Out of the 15 two of them are timestamp, at least one of these two timestamp columns is always in the where clause the queries.
Now the challenge is, the queries we run can have any combination of the 13 other columns + one timestamp. In reality the queries never have more than 7 or 8 columns in the where clause but even if we had only 4 columns in the where clause we would still have the same problem.
So if I create one concatenated index for all these columns it will not be very efficient because after the 4th or 5th column the sorting would no longer be very useful and I believe the optimiser would simply not use the rest of the index. So queries that use the leading columns of the index in sequence work well, but if I need to query the 10th column the I have performance issues.
Now, if I create multiple single column indexes oracle will have to work a lot harder to maintain all these indexes and it will create performance issues (I have tried that). Besides, if I have multiple single column indexes the optimiser will do nested loops twice or three times and will hit only the first few columns of the where clause so I think it will kind of be the same as the long concatenated index.
What I am trying to do is exactly what the Bitmap index would do, it would be very good if I could use the AND condition that a Bitmap index uses. This way I could have N number of single column indexes which the optimiser could pick from and serve the query with exactly the ones it needs. But unfortunately using the Bitmap index here is not an option given the large amount of inserts that I get on this table.
I have been looking for alternatives, I have considered creating multiple shorter concatenated indexes but this still would not address the issue since many queries would still not be served properly and therefore would take a very long time to complete.
What I had in mind would be some sort of multidimensional index, I am not even sure if such thing exists. But essentially it would be some sort of index that could serve a query efficiently regardless of the fact that the where clause has the 1st, 3rd and last columns of the index.
So considering how widely used Oracle is and how many super large databases there are out there, this problem must be common.
I am on 11.2.0.3 Enterprise Edition. We are using the new feature "Composite Domain Index" for a Domain index on a very large table (>250.000.000 rows). It really works with mixed queries. We added two number columns using FILTER BY.We have lots of DML on this table. Therefore, we are executing synchronize and optimize once the week. The synch behaves pretty normal. But "optimize_index" takes a very very long time to complete. I have switsched on 'logging' for the optimize process. The $I table takes some time but is finished normally. But the optimization of the $S table (that is the table created for the CDI feature) is running over 12 hours now - and far from being finished. From the logfile, I can see that it optimizes 1000 rows every 20 minutes. Here is the output of the logfile:
Oracle Text, 11.2.0.3.0
14:33:05 06/26/12 begin logging
14:33:05 06/26/12 event
14:33:05 06/26/12 process $N for optimize: SEQDEV.GEN_GES_DESCRIPTION_CTX_I
14:33:16 06/26/12
14:33:16 06/26/12
[code]....
I haven't found a recommendation from Oracle not to use "optimize_index" for Domain Indexes with CDI. But in my case, it would be much faster just to drop and recreate the Domain Index in question.
I have a huge table (about 60 gb) partition over range. The index on this table is global index created on 4 columns together. I have a query which is running very slowly. The explain plan is showing the use of this global index.Explain plan is not showing pstart and pend because the index is global.
View 6 Replies View RelatedI have a global index and I want to convert it to local index.Is there a way to recreate local index with out dropping the global index.
I can create a local index first and then drop the global index. But is there a way to create it with out dropping the global index, just convert it.
I am facing the error "ORA-01502: index or partition of such index is in unusable state " while loading the text data using
sql loader with direct path (direct = Y ,rows = 10000) option. Table consists an composite non unique index. If I query the dba indexes for the effected index it shows the index status as VALID. There was no maintaince done on the effected table or index. I have tried loading the same data using conventional path but didn't found any issues for the same.
I have a query which had a join:
a.c1=b.c1 and a.c2=@var
where @var is user supplied input at runtime...We had a index on a.c2 . The CBO would use this index to generate an opitimised query plan.We found some records from table "b" were dropping due to inner join. So we made a change in join. It'd be like
a.c1(+)=b.c1 and nvl(a.c2,@var)=@var
This query is no longer using the index, instead its doing a full table scan causing the query to slowdown.I have tried creating index on nvl(a.c2,'31-dec-9999')
But the CBO won't use it.Anyway to create index on this col so that full table scan can be avoided?
How to force an index if the table not using the index?
View 10 Replies View RelatedWe have occurrences of enq : TX - index contentions in the database. Using the SQL ID, we have identified the INSERT statement and the table which they are trying to insert.
This table has almost 25 different indexes, some of which are unique as well.I am wondering how to identify the actual index causing issue, out of these 25 indexes.
Is there any way to pin point to the name of index which is causing the lock?My plan is, once the index is identified, I would like to check the extents and inittrans and other attributes of this index to fix.
can we use something like this
"select ... order by emp from emp"
what is to be done? so that this qurey runs. no co-related subquery to be used.
Can we create non-cluster index on a clustered index?
View 5 Replies View RelatedAny on give explanation for difference between Index and Clustered Index?
It will be great if i get explanation how memory allocation and Execution takes place.?
What is the difference between index rebuild and index rebuild online.
View 3 Replies View RelatedI have a table with the following fields :
RGS_CAN_PERIOD NUMBER(4)
RGS_ID_ELECTOR NUMBER(
FBD_NID VARCHAR2(14)
RGS_SURNAME VARCHAR2(40)
RGS_O_NAME VARCHAR2(40)
RGS_ALIAS VARCHAR2(30)
RGS_ADDR VARCHAR2(75)
RGS_ID_REG_AREA VARCHAR2(3)
[Code]..
I need a report as hereunder :
Reg. Area Age <=19 20 <= Age <= 24 25 <=Age <= 29 Total No. of Voters
xxxx 10 15 7 32
yyyy 5 7 3 15
I have work out a script but the age is not in a range
select *
FROM (select rgs_id_reg_area,
count(decode(fbd_age,19,fbd_age)) Age19,
count(decode(fbd_age,20,fbd_age)) Age20
FROM rubyvoterstat where vote ='Y'
GROUP by rgs_id_reg_area)
order by rgs_id_reg_area
In my prod table few partition need to be added.
I tried below both syntax, but I am getting error
1)
Alter table STS.DNA_ACCESSION add PARTITION DNA_ACC_P143 VALUES LESS THAN (286000000);
ORA-14074: partition bound must collate higher than that of the last partition
2)
ALTER TABLE STS_RO.DNA_ACCESSION
SPLIT PARTITION DNA_ACC_P999 AT VALUES LESS THAN (286000000)
INTO (PARTITION DNA_ACC_P143,
[Code]....
I have table :TABLE_X and want to select some data locate into specific range of Day/Month. But so far i couldn't find out the way to.
For example, i want to select people born within specific range of date(range : sysdate to (sysdate+7months ahead) Year here should not be consider, only the day and month.
e.g. a range could be from today:Sept,20 to Apr,18.
so what i was trying is to select doing the following.
select TABLE_X_ID, TABLE_X_BIRTH_DATE
from TABLE_X
where to_date(TABLE_X_BIRTH_DATE, 'DD/MM')
between to_date (to_char(SYSDATE, 'DD/MM'), 'DD/MM')
and to_date (to_char(SYSDATE+210, 'DD/MM'), 'DD/MM')
first am not sure if BETWEEN & AND will work for this case, bt it was the most logical way i could think about to get such range.
I have a table like this:
x y AMNT
---------------------------------------
1 120 12
1 120 93
1 125 31
1 260 15
2 56 16
2 115 49
3 45 71
4 19 11
4 16 48
5 94 52
5 98 47
I want to group records on x , y columns and aggregate on amnt column, in which difference between values of y column be less than 10.
The result is like this:
x y sum(AMNT)
------------------------------------------------
1 ? 136
1 260 15
2 56 16
2 115 49
3 45 71
4 ? 59
5 ? 99
What query can I use?
this is my table
create table sequence ( id int not null primary key);
insert into sequence(id) values
(1), (2), (3), (4), (6), (7), (8), (9),
(10), (15), (16), (17), (18), (19), (20),(22);
i need the answer to group the sequence like this
start_number | end_number | count
1 | 4 | 4
6 | 10 | 5
15 | 20 | 6
22 | 22 | 1
what should i do?
I am trying to break down the balance_date to display the following groupings:
7:00-17:30 CDT
18:00-4:30 CDT
I currently have the query setup to display by day instead of these time ranges. I would like the output to read
19 May Day
19 May Night
20 May Day
20 May Night
I am fairly new to this, but how would I go about making this change?
SELECT
TO_CHAR(TRUNC(balance_date,'D') + 4,'YYYY') || '-' ||
TO_CHAR(TRUNC(balance_date,'D') + 4,'IW') as year_wk,
TO_CHAR(TRUNC(balance_date,'D') + 4,'IW')as wk,
[Code] ........
I am trying to create a SQL query which will check that various postcode formats are valid, but I am having trouble getting oracle sql to check for values within ranges - for example the following returns no rows, even though most of the postcodes I am dealing with start with 'P'.
select postcode from mytable.addresses
where postcode like '[N-R]%'
;
Am I getting my syntax wrong somewhere?