Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

tiflash: Remove the description about expr_blacklist in use_tiflash.md #6188

Merged
merged 1 commit into from
Aug 26, 2021
Merged

tiflash: Remove the description about expr_blacklist in use_tiflash.md #6188

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 1 addition & 3 deletions tiflash/use-tiflash.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -246,14 +246,12 @@ Currently, TiFlash supports the following push-down expressions:
* Logical functions: `and, or, not, case when, if, ifnull, isnull, in, like, coalesce`
* Bitwise operations: `bitand, bitor, bigneg, bitxor`
* String functions: `substr, char_length, replace, concat, concat_ws, left, right, ascii, length, trim, position`
* Date functions: `date_format, timestampdiff, from_unixtime, unix_timestamp(int), unix_timestamp(decimal), str_to_date(date), str_to_date(datetime), date_add(datetime, int), date_add(string, int), date_add(string, real), date_sub(datetime, int), date_sub(string, int), datediff, year, month, day, extract(datetime), date`
* Date functions: `date_format, timestampdiff, from_unixtime, unix_timestamp(int), unix_timestamp(decimal), str_to_date(date), str_to_date(datetime), datediff, year, month, day, extract(datetime), date`
* JSON function: `json_length`
* Conversion functions: `cast(int as double), cast(int as decimal), cast(int as string), cast(int as time), cast(double as int), cast(double as decimal), cast(double as string), cast(double as time), cast(string as int), cast(string as double), cast(string as decimal), cast(string as time), cast(decimal as int), cast(decimal as string), cast(decimal as time), cast(time as int), cast(time as decimal), cast(time as string)`
* Aggregate functions: `min, max, sum, count, avg, approx_count_distinct`
* Miscellaneous functions: `inetntoa, inetaton, inet6ntoa, inet6aton`

Among them, the push-down of `cast` and `date_add` is not enabled by default. To enable it, refer to [Blocklist of Optimization Rules and Expression Pushdown](/blocklist-control-plan.md).

In addition, expressions that contain the Time/Bit/Set/Enum/Geometry type cannot be pushed down to TiFlash.

If a query encounters unsupported push-down calculations, TiDB needs to complete the remaining calculations, which might greatly affect the TiFlash acceleration effect. The currently unsupported operators and expressions might be supported in future versions.
Expand Down