Mixing
How to use Limit in query on my index column without scan all rows?
6
Here is my table :
In my table
Clustering_key(Primary key and auto incremental)
ID(Index Column)
Data(Text datatype column)
Position(Index column) maintain the order ofData
My table have 90,000 rows with same ID equal to 5. I want to first 3 rows with ID equal to 5 and my query like this
Select * from mytable where ID=5 Limit 3;
ID column is index column So I think mysql scan only first 3 rows but mysql scan around 42000 rows.
Here Explain query :
Any possibility to avoid all rows scan.
Please give me some solution
Thanks in advance
mysql database innodb
asked Nov 17 '18 at 10:55
ShubhamShubham
819
|
show 9 more comments
6
Here is my table :
In my table
Clustering_key(Primary key and auto incremental)
ID(Index Column)
Data(Text datatype column)
Position(Index column) maintain the order ofData
My table have 90,000 rows with same ID equal to 5. I want to first 3 rows with ID equal to 5 and my query like this
Select * from mytable where ID=5 Limit 3;
ID column is index column So I think mysql scan only first 3 rows but mysql scan around 42000 rows.
Here Explain query :
Any possibility to avoid all rows scan.
Please give me some solution
Thanks in advance
mysql database innodb
asked Nov 17 '18 at 10:55
ShubhamShubham
819
2
What is your PRIMARY KEY? (It sounds like it should be a combination of id and position), and that the separate index on id is therefore redundant.
– Strawberry
Nov 17 '18 at 10:59
MySQL has to scan all the row because ofOrder By Positionas it needs to first sort them all. Try adding a composite index (id,position)
– Madhur Bhaiya
Nov 17 '18 at 11:00
@Madhur I try this but its doesn't affect the results. if i execute same query. This composite key is useful when i usePositionin where clause like Select * from mytable where ID=5 and Position> xyz and Position < xyz;
– Shubham
Nov 17 '18 at 13:05
@Madhur I removeOrder By Positionin my query but result are same . I think reason of scan all rows isID=5but i am using index on this column.
– Shubham
Nov 17 '18 at 13:15
@Shubham please addEXPLAINstatement results to the question.
– Madhur Bhaiya
Nov 17 '18 at 13:17
|
show 9 more comments
6
6
6
1
Here is my table :
In my table
Clustering_key(Primary key and auto incremental)
ID(Index Column)
Data(Text datatype column)
Position(Index column) maintain the order ofData
My table have 90,000 rows with same ID equal to 5. I want to first 3 rows with ID equal to 5 and my query like this
Select * from mytable where ID=5 Limit 3;
ID column is index column So I think mysql scan only first 3 rows but mysql scan around 42000 rows.
Here Explain query :
Any possibility to avoid all rows scan.
Please give me some solution
Thanks in advance
mysql database innodb
asked Nov 17 '18 at 10:55
ShubhamShubham
819
Here is my table :
In my table
Clustering_key(Primary key and auto incremental)
ID(Index Column)
Data(Text datatype column)
Position(Index column) maintain the order ofData
My table have 90,000 rows with same ID equal to 5. I want to first 3 rows with ID equal to 5 and my query like this
Select * from mytable where ID=5 Limit 3;
ID column is index column So I think mysql scan only first 3 rows but mysql scan around 42000 rows.
Here Explain query :
Any possibility to avoid all rows scan.
Please give me some solution
Thanks in advance
mysql database innodb
mysql database innodb
asked Nov 17 '18 at 10:55
ShubhamShubham
819
asked Nov 17 '18 at 10:55
ShubhamShubham
819
edited Nov 21 '18 at 6:40
Shubham
asked Nov 17 '18 at 10:55
ShubhamShubham
819
asked Nov 17 '18 at 10:55
ShubhamShubham
819
asked Nov 17 '18 at 10:55
ShubhamShubham
819
819
2
What is your PRIMARY KEY? (It sounds like it should be a combination of id and position), and that the separate index on id is therefore redundant.
– Strawberry
Nov 17 '18 at 10:59
MySQL has to scan all the row because ofOrder By Positionas it needs to first sort them all. Try adding a composite index (id,position)
– Madhur Bhaiya
Nov 17 '18 at 11:00
@Madhur I try this but its doesn't affect the results. if i execute same query. This composite key is useful when i usePositionin where clause like Select * from mytable where ID=5 and Position> xyz and Position < xyz;
– Shubham
Nov 17 '18 at 13:05
@Madhur I removeOrder By Positionin my query but result are same . I think reason of scan all rows isID=5but i am using index on this column.
– Shubham
Nov 17 '18 at 13:15
@Shubham please addEXPLAINstatement results to the question.
– Madhur Bhaiya
Nov 17 '18 at 13:17
|
show 9 more comments
2
What is your PRIMARY KEY? (It sounds like it should be a combination of id and position), and that the separate index on id is therefore redundant.
– Strawberry
Nov 17 '18 at 10:59
MySQL has to scan all the row because ofOrder By Positionas it needs to first sort them all. Try adding a composite index (id,position)
– Madhur Bhaiya
Nov 17 '18 at 11:00
@Madhur I try this but its doesn't affect the results. if i execute same query. This composite key is useful when i usePositionin where clause like Select * from mytable where ID=5 and Position> xyz and Position < xyz;
– Shubham
Nov 17 '18 at 13:05
@Madhur I removeOrder By Positionin my query but result are same . I think reason of scan all rows isID=5but i am using index on this column.
– Shubham
Nov 17 '18 at 13:15
@Shubham please addEXPLAINstatement results to the question.
– Madhur Bhaiya
Nov 17 '18 at 13:17
2
2
What is your PRIMARY KEY? (It sounds like it should be a combination of id and position), and that the separate index on id is therefore redundant.
– Strawberry
Nov 17 '18 at 10:59
What is your PRIMARY KEY? (It sounds like it should be a combination of id and position), and that the separate index on id is therefore redundant.
– Strawberry
Nov 17 '18 at 10:59
MySQL has to scan all the row because of
Order By Position as it needs to first sort them all. Try adding a composite index (id, position)– Madhur Bhaiya
Nov 17 '18 at 11:00
MySQL has to scan all the row because of
Order By Position as it needs to first sort them all. Try adding a composite index (id, position)– Madhur Bhaiya
Nov 17 '18 at 11:00
@Madhur I try this but its doesn't affect the results. if i execute same query. This composite key is useful when i use
Position in where clause like Select * from mytable where ID=5 and Position> xyz and Position < xyz;– Shubham
Nov 17 '18 at 13:05
@Madhur I try this but its doesn't affect the results. if i execute same query. This composite key is useful when i use
Position in where clause like Select * from mytable where ID=5 and Position> xyz and Position < xyz;– Shubham
Nov 17 '18 at 13:05
@Madhur I remove
Order By Position in my query but result are same . I think reason of scan all rows is ID=5 but i am using index on this column.– Shubham
Nov 17 '18 at 13:15
@Madhur I remove
Order By Position in my query but result are same . I think reason of scan all rows is ID=5 but i am using index on this column.– Shubham
Nov 17 '18 at 13:15
@Shubham please add
EXPLAIN statement results to the question.– Madhur Bhaiya
Nov 17 '18 at 13:17
@Shubham please add
EXPLAIN statement results to the question.– Madhur Bhaiya
Nov 17 '18 at 13:17
|
show 9 more comments
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2
What is your PRIMARY KEY? (It sounds like it should be a combination of id and position), and that the separate index on id is therefore redundant.
– Strawberry
Nov 17 '18 at 10:59
MySQL has to scan all the row because of
Order By Positionas it needs to first sort them all. Try adding a composite index (id,position)– Madhur Bhaiya
Nov 17 '18 at 11:00
@Madhur I try this but its doesn't affect the results. if i execute same query. This composite key is useful when i use
Positionin where clause like Select * from mytable where ID=5 and Position> xyz and Position < xyz;– Shubham
Nov 17 '18 at 13:05
@Madhur I remove
Order By Positionin my query but result are same . I think reason of scan all rows isID=5but i am using index on this column.– Shubham
Nov 17 '18 at 13:15
@Shubham please add
EXPLAINstatement results to the question.– Madhur Bhaiya
Nov 17 '18 at 13:17