computed index by substring function for long columns [CORE3672] #4022
Assignees
Comments
|
Commented by: Sean Leyne (seanleyne) What is the definition (data type & length) of "Col1"? |
|
Commented by: Lukas Masak (lmasak) CREATE TABLE tbl_test |
Modified by: @asfernandesassignee: Adriano dos Santos Fernandes [ asfernandes ] |
Modified by: @asfernandesstatus: Open [ 1 ] => Resolved [ 5 ] resolution: Fixed [ 1 ] Fix Version: 3.0 Alpha 1 [ 10331 ] |
Modified by: @pavel-zotovstatus: Resolved [ 5 ] => Resolved [ 5 ] Test Details: Confirmed in 2.5.5 (29-may-2015): attempt to create COMPUTED_BY index on expressions that involves UTF8-field with declared length = 169 characters (and page_size = 4K) produced: |
Modified by: @pavel-zotovstatus: Resolved [ 5 ] => Closed [ 6 ] |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Submitted by: Lukas Masak (lmasak)
Is related to QA568
It is not possible to use substring function to create computed index for large columns.
CREATE INDEX IDX1 ON tbl_test COMPUTED BY (SUBSTRING(col1 from 1 for 20))
will fail with message: key size exceeds implementation restriction for index "IDX1"
select char_length( SUBSTRING(col1 from 1 for 20)) from tbl_test returns 20 so I was expecting index to work.
workaround
CREATE INDEX IDX1 ON tbl_test COMPUTED BY (CAST(SUBSTRING(col1 from 1 for 20) as varchar(20)))
Commits: d50019f c90e3a8 86d787b
====== Test Details ======
Confirmed in 2.5.5 (29-may-2015): attempt to create COMPUTED_BY index on expressions that involves UTF8-field with declared length = 169 characters (and page_size = 4K) produced:
"-key size exceeds implementation restriction"
The text was updated successfully, but these errors were encountered: