hotspot of TiFlash #3900 • TiFlash – Add operators: MOD / %, LIKE – Add string functions: ASCII(), COALESCE(), LENGTH(), POSITION(), TRIM() – Add mathematical functions: CONV(), CRC32(), DEGREES(), EXP() supported: – PARTITION BY KEY – SUBPARTITION – {CHECK|OPTIMIZE|REPAIR|IMPORT|DISCARD|REBUILD|REORGANIZE|COALESCE} �→ PARTITION 2.6.2.6 Analyze table Statistics Collection works differently in TiDB than in MySQL functions and operators <, <=, =, != (<>), >, >=, <=>, IN(), IS NULL, LIKE, IS TRUE, IS FALSE, COALESCE() Numeric functions and operators +, -, *, /, ABS(), CEIL(), CEILING(), FLOOR() Control flow

PARTITION BY KEY 76 – SUBPARTITION – {CHECK|OPTIMIZE|REPAIR|IMPORT|DISCARD|REBUILD|REORGANIZE|COALESCE} �→ PARTITION For more details, see Partitioning. 2.6.2.6 Analyze table Statistics Collection functions and operators <, <=, =, != (<>), >, >=, <=>, IN(), IS NULL, LIKE, IS TRUE, IS FALSE, COALESCE() Numeric functions and operators +, -, *, /, ABS(), CEIL(), CEILING(), FLOOR() Control flow degrees, conv, crc32 • 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

supported: – PARTITION BY KEY – SUBPARTITION – {CHECK|OPTIMIZE|REPAIR|IMPORT|DISCARD|REBUILD|REORGANIZE|COALESCE} �→ PARTITION 2.6.2.6 Analyze table Statistics Collection works differently in TiDB than in MySQL functions and operators <, <=, =, != (<>), >, >=, <=>, IN(), IS NULL, LIKE, IS TRUE, IS FALSE, COALESCE() Numeric functions and operators +, -, *, /, ABS(), CEIL(), CEILING(), FLOOR() Control flow CHARACTER (R) • CHARSET • CHECK (R) • CHECKPOINT • CHECKSUM • CIPHER • CLEANUP • CLIENT • CMSKETCH (R) • COALESCE • COLLATE (R) • COLLATION • COLUMN (R) • COLUMNS • COLUMN_FORMAT • COMMENT • COMMIT • COMMITTED

热点调度支持对 TiFlash 的写热点进行调度 #3900 32 • TiFlash – 新增若干运算符的支持：MOD / %, LIKE – 新增若干字符串函数的支持：ASCII(), COALESCE(), LENGTH(), POSITION(), TRIM() – 新增若干数学函数的支持：CONV(), CRC32(), DEGREES(), EXP(), LN(), LOG(), LOG10() – PARTITION BY KEY – SUBPARTITION – {CHECK|OPTIMIZE|REPAIR|IMPORT|DISCARD|REBUILD|REORGANIZE|COALESCE} PARTITION 2.6.2.6 ANALYZE TABLE TiDB 中的信息统计与 MySQL 中的有所不同：TiDB 中的信息统计会完全重构表的统计数据，语句执行过程较长， 但在 OR (||), NOT (!) 比较运算 <, <=, =, != (<>), >, >=, <=>, IN(), IS NULL, LIKE, IS TRUE, IS FALSE, COALESCE() 数值运算 +, -, *, /, ABS(), CEIL(), CEILING(), FLOOR() 控制流运算 CASE, IF(), IFNULL() JSON 运算 JSON_TYPE(json_val)

– PARTITION BY KEY – SUBPARTITION – {CHECK|OPTIMIZE|REPAIR|IMPORT|DISCARD|REBUILD|REORGANIZE|COALESCE} PARTITION 2.6.2.6 ANALYZE TABLE TiDB 中的信息统计 与 MySQL 中的有所不同：TiDB 中的信息统计会完全重构表的统计数据，语句执行过程较长， 但在 OR (||), NOT (!) 比较运算 <, <=, =, != (<>), >, >=, <=>, IN(), IS NULL, LIKE, IS TRUE, IS FALSE, COALESCE() 数值运算 +, -, *, /, ABS(), CEIL(), CEILING(), FLOOR() 控制流运算 CASE, IF(), IFNULL() JSON 运算 JSON_TYPE(json_val) CHARSET • CHECK (R) • CHECKPOINT • CHECKSUM • CIPHER • CLEANUP • CLIENT • CMSKETCH (R) • COALESCE • COLLATE (R) • COLLATION • COLUMN (R) • COLUMNS • COLUMN_FORMAT • COMMENT • COMMIT • COMMITTED

– PARTITION BY KEY – SUBPARTITION – {CHECK|OPTIMIZE|REPAIR|IMPORT|DISCARD|REBUILD|REORGANIZE|COALESCE} PARTITION 更多详情，请参考分区表文档。 2.6.2.6 ANALYZE TABLE TiDB 中的信息统计与 MySQL 中的有所不同：TiDB 中的信息统计会完全重构表的统计数据，语句执行过程较长， OR (||), NOT (!) 比较运算 <, <=, =, != (<>), >, >=, <=>, IN(), IS NULL, LIKE, IS TRUE, IS FALSE, COALESCE() 数值运算 +, -, *, /, ABS(), CEIL(), CEILING(), FLOOR() 控制流运算 CASE, IF(), IFNULL() JSON 运算 JSON_TYPE(json_val) sign, radians, degrees, conv, crc32 • 逻辑函数：and, or, not, case when, if, ifnull, isnull, in, like, coalesce • 位运算：bitand, bitor, bigneg, bitxor • 字 符 串 函 数：substr, char_length, replace, concat, concat_ws

supported: – PARTITION BY KEY – SUBPARTITION – {CHECK|OPTIMIZE|REPAIR|IMPORT|DISCARD|REBUILD|REORGANIZE|COALESCE} �→ PARTITION For more details, see Partitioning. 2.6.2.6 Analyze table Statistics Collection functions and operators <, <=, =, != (<>), >, >=, <=>, IN(), IS NULL, LIKE, IS TRUE, IS FALSE, COALESCE() Numeric functions and operators +, -, *, /, ABS(), CEIL(), CEILING(), FLOOR() Control flow degrees, conv, crc32 • 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

– PARTITION BY KEY – SUBPARTITION – {CHECK|OPTIMIZE|REPAIR|IMPORT|DISCARD|REBUILD|REORGANIZE|COALESCE} PARTITION 更多详情，请参考分区表文档。 2.6.2.6 ANALYZE TABLE TiDB 中的信息统计与 MySQL 中的有所不同：TiDB 中的信息统计会完全重构表的统计数据，语句执行过程较长， OR (||), NOT (!) 比较运算 <, <=, =, != (<>), >, >=, <=>, IN(), IS NULL, LIKE, IS TRUE, IS FALSE, COALESCE() 数值运算 +, -, *, /, ABS(), CEIL(), CEILING(), FLOOR() 控制流运算 CASE, IF(), IFNULL() JSON 运算 JSON_TYPE(json_val) sign, radians, degrees, conv, crc32 • 逻辑函数：and, or, not, case when, if, ifnull, isnull, in, like, coalesce • 位运算：bitand, bitor, bigneg, bitxor • 字 符 串 函 数：substr, char_length, replace, concat, concat_ws

· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 6016 17.3.2 Coalesce Partition · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · be reused when the HashJoin operator per- forms probe #48082 @wshwsh12 • Fix the issue that the COALESCE() function returns incorrect result type for DATE type parameters #46475 @xzhangxian1008 • Fix N N N N N N N EXCHANGE PARTITION Y Y Y E E E E E E N REORGANIZE PARTITION Y Y N N N N N N N N COALESCE PARTITION Y Y N N N N N N N N Dynamic pruning Y Y Y Y E E E E N N Range COLUMNS partitioning Y

· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 6119 17.3.2 Coalesce Partition · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · N N N N N EXCHANGE PARTITION Y Y Y Y E E E E E E N REORGANIZE PARTITION Y Y Y N N N N N N N N COALESCE PARTITION Y Y Y N N N N N N N N Dynamic pruning Y Y Y Y Y E E E E N N Range COLUMNS partitioning operations. Other partition operations are ignored. • Hash and Key partitioned tables support ADD, COALESCE, and TRUNCATE operations. Other partition operations are ignored. • The following syntaxes are