Questions tagged [full-table-scan]
61 questions
0
votes
2 answers
SQL Server ignoring index and performs table scan
we have a little problem with one of our queries, which is executed inside a .Net (4.5) application via System.Data.SqlClient.SqlCommand.
The problem is, that the query is going to perform a Table-Scan which is very slow. So the execution plan shows…
slxSlashi
- 267
- 1
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- 11
0
votes
2 answers
MySql - Full Table Scan on JOIN query
I have the following MySql table (only 845 rows):
CREATE TABLE `categories_nested_set` (
`lft` int(11) NOT NULL DEFAULT '0',
`rgt` int(11) DEFAULT NULL,
`id` int(11) DEFAULT NULL,
`category` varchar(128) DEFAULT NULL,
PRIMARY KEY (`lft`),
…
mils
- 1,878
- 2
- 21
- 42
0
votes
1 answer
Ways to optimize memory usage for query with aggregate functions on very large tables in Oracle
I have a table with large amount of data(Say 1,000,000,000 rows).
Table Structure:
Id(Primary Key)
Name
...
I have omitted other fields from the table as I cannot use any of those to limit the data I fetch.
Here primary key is Id. I do not have any…
Minnu perinchery
- 11
- 2
0
votes
2 answers
How to make full table scans faster in Oracle database?
This is a simple question. Suppose I have a massive table (5 million rows), and I have no option but to do a full table scan.
SELECT * FROM Table1
Is there any way at all to make my database return the results faster?
Background:
We have an…
painiyff
- 2,519
- 6
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0
votes
1 answer
Avoid Full Table Scan - Extract First Row Only
I am trying to write a query that only extract the first (random) row when condition is met.
-- Create table
create table TRANSACTIONS_SAMPLE
(
institution_id NUMBER(5) not null,
id NUMBER(10) not null,
…
MrM
- 389
- 1
- 8
- 23
0
votes
1 answer
query efficiency - select the 2 latest “group/batch” records from table
We have a tested a quite interesting SQL query. Unfortunately, It turned out that this query runs a little bit slow - O(n2) - and we are looking for a optimized solution or maybe also a totally different one?
Goal:
We would like to get for:
- some…
cahro88
- 7
- 4
0
votes
1 answer
MySQL query does not use index
The following query:
EXPLAIN
SELECT
fdb . * ,
TIME_FORMAT( fdb.scheme, '%H:%i' ) AS scheme,
TIME_FORMAT( fdb.actual, '%H:%i' ) AS actual,
TIME_FORMAT( fdb.baggage, '%H:%i' ) AS baggage,
TIME_FORMAT( fdb.baggage_handled, …
edwardmp
- 6,339
- 5
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- 77
0
votes
1 answer
How to scan a big mysql table in parallel?
Suppose we have a big mysql table, which has less than 10 million rows.
If I want to select all the results, obviously a full table scan works fine.
select * from table_name;
But how to make it in parallel? I found the solution in Sqoop is…
hahakubile
- 6,978
- 4
- 28
- 18
0
votes
2 answers
Avoid full table scan by a different select
Why does the first query use full table scan while the second uses index?
SELECT *
FROM emp
WHERE job = 'PRESIDENT';
and
SELECT job
FROM emp
WHERE job = 'PRESIDENT';
user3141805
- 23
- 4
0
votes
1 answer
EXPLAIN PLAN needs to long
I am trying to figure out why the query needs so long, so I can optimize it.
I tried it with EXPLAIN:
EXPLAIN SELECT * FROM (
SELECT p.*, ol. prod_id olpid
FROM products p LEFT JOIN orderlines ol
ON p. prod_id = ol. prod_id ) pol
WHERE pol. olpid…
JOP
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- 9
0
votes
1 answer
mysql searching in various fields with OR performing full table scan
I have 3 tables (not writing all and actual field names)
Contract (~30 000 rows)
|id|client_id|contract_nr|....
Container (~30 000 rows
|id|contract_nr|phone_1(varchar)|....
Client (~35 000…
uldis.zarins
- 406
- 4
- 5
0
votes
2 answers
oracle does full table scan but returns resutls so quickly
When I open up TOAD and do a select * from table,the results (first 500 rows) come back almost instantly. But the explain plan shows full table scan and the table is very huge.
How come the results are so quick?
Victor
- 16,609
- 71
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- 409
0
votes
0 answers
Mysql full table scan of index
I have 3,090,590 rows in a message column and I am using this code to get 3000 rows at a time.
I am trying to convert my SQL to NoSQL, for this I wrote a PHP script with Ajax. Ajax requests $page every time by multiplying; for e.g. 3000, 9000,…
Ejderha Katili
- 41
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- 7
-1
votes
1 answer
full table scan in mysql
select *from REPT_AIR_PRY_HY1 RAP where
(RAP.DATE_OF_ISSUE) BETWEEN "2017-10-01" AND DATE_ADD("2017-10-31", INTERVAL 1 DAY)
the explain plan of this query gives me 337243
but data s between these dates is only 55209 and there is even index is…
sathish Anandan
- 1
- 8
-1
votes
2 answers
MySql - Self Join - Full Table Scan (Cannot Scan Index)
I have the following self-join query:
SELECT A.id
FROM mytbl AS A
LEFT JOIN mytbl AS B
ON (A.lft BETWEEN B.lft AND B.rgt)
The query is quite slow, and after looking at the execution plan the cause appears to be a full table scan in the JOIN.…
mils
- 1,878
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- 42