How DB index works internally at high level?
I have around 500 GB of data in one table of MySQL which has around 5 billion records. It has around 15 columns. It has index on all the required columns. When I do select * from big_table where index_column = some_value it takes couple of minutes to return the data.
I am not sure how indexing works internally here.Here is my understanding
- DB vendor will bring indexed column data in memory first
- Find the values(searched in query) under indexed data fetched in to memory to get the record row location in actual table.
- Then another IO call will go to disk to get all required data based on row location fetched in step_2
Is that correct ?
mysql index
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user3198603user3198603
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I have around 500 GB of data in one table of MySQL which has around 5 billion records. It has around 15 columns. It has index on all the required columns. When I do select * from big_table where index_column = some_value it takes couple of minutes to return the data.
I am not sure how indexing works internally here.Here is my understanding
- DB vendor will bring indexed column data in memory first
- Find the values(searched in query) under indexed data fetched in to memory to get the record row location in actual table.
- Then another IO call will go to disk to get all required data based on row location fetched in step_2
Is that correct ?
mysql index
asked 5 mins ago
user3198603user3198603
1797
add a comment |
I have around 500 GB of data in one table of MySQL which has around 5 billion records. It has around 15 columns. It has index on all the required columns. When I do select * from big_table where index_column = some_value it takes couple of minutes to return the data.
I am not sure how indexing works internally here.Here is my understanding
- DB vendor will bring indexed column data in memory first
- Find the values(searched in query) under indexed data fetched in to memory to get the record row location in actual table.
- Then another IO call will go to disk to get all required data based on row location fetched in step_2
Is that correct ?
mysql index
asked 5 mins ago
user3198603user3198603
1797
I have around 500 GB of data in one table of MySQL which has around 5 billion records. It has around 15 columns. It has index on all the required columns. When I do select * from big_table where index_column = some_value it takes couple of minutes to return the data.
I am not sure how indexing works internally here.Here is my understanding
- DB vendor will bring indexed column data in memory first
- Find the values(searched in query) under indexed data fetched in to memory to get the record row location in actual table.
- Then another IO call will go to disk to get all required data based on row location fetched in step_2
Is that correct ?
mysql index
mysql index
asked 5 mins ago
user3198603user3198603
1797
asked 5 mins ago
user3198603user3198603
1797
asked 5 mins ago
user3198603user3198603
1797
asked 5 mins ago
user3198603user3198603
1797
asked 5 mins ago
user3198603user3198603
1797
1797
add a comment |
add a comment |
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