tiflash: clarify signature of function date_add push down

releases/release-5.4.0.md

@@ -121,7 +121,7 @@ In v5.4, the key new features or improvements are as follows:
     - Support pusing down more functions to the MPP engine:
 
         - String functions: `LPAD()`, `RPAD()`, `STRCMP()`
-        - Date functions: `ADDDATE()`, `DATE_ADD()`, `DATE_SUB()`, `SUBDATE()`, `QUARTER()`
+        - Date functions: `ADDDATE(string, real)`, `DATE_ADD(string, real)`, `DATE_SUB(string, real)`, `SUBDATE(string, real)`, `QUARTER()`
 
     - Introduce the elastic thread pool feature to improve resource utilization (experimental)
     - Improve the efficiency of converting data from row-based storage format to column-based storage format when replicating data from TiKV, which brings 50% improvement in the overall performance of data replication

tiflash/tiflash-supported-pushdown-calculations.md

@@ -37,7 +37,7 @@ TiFlash supports the following push-down expressions:
 * Logical functions: `and, or, not, case when, if, ifnull, isnull, in, like, coalesce, is`
 * Bitwise operations: `bitand, bitor, bigneg, bitxor`
 * String functions: `substr, char_length, replace, concat, concat_ws, left, right, ascii, length, trim, ltrim, rtrim, position, format, lower, ucase, upper, substring_index, lpad, rpad, strcmp, regexp, regexp_like, regexp_instr, regexp_substr`
-* 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, hour, microsecond, minute, second, sysdate, date_add, date_sub, adddate, subdate, quarter, dayname, dayofmonth, dayofweek, dayofyear, last_day, monthname, to_seconds, to_days, from_days, weekofyear`
+* 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, hour, microsecond, minute, second, sysdate, date_add/adddate(datetime, int), date_add/adddate(string, int), date_add/adddate(string, real), date_sub/subdate(datetime, int), date_sub/subdate(string, int), date_sub/subdate(string, real), quarter, dayname, dayofmonth, dayofweek, dayofyear, last_day, monthname, to_seconds, to_days, from_days, weekofyear`
 * JSON function: `json_length, ->, ->>, json_extract`
 * 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), cast(time as real)`
 * Aggregate functions: `min, max, sum, count, avg, approx_count_distinct, group_concat`