# Functions
GetGlobalSystemVar gets a global system variable.
GetScopeNoneSystemVar checks the validation of `key`, and return the default value if its scope is `ScopeNone`.
GetSessionOnlySysVars get the default value defined in code for session only variable.
GetSessionSystemVar gets a system variable.
GetStatusVars gets registered statistics status variables.
GetSysVar returns sys var info for name as key.
GoTimeToTS converts a Go time to uint64 timestamp.
NewSessionVars creates a session vars object.
RegisterStatistics registers statistics.
SetSessionSystemVar sets system variable and updates SessionVars states.
# Constants
special session variables.
CharacterSetConnection is the name for character_set_connection system variable.
special session variables.
CharsetDatabase is the name for character_set_database system variable.
Variable error codes.
Variable error codes.
Variable error codes.
Variable error codes.
Variable error codes.
CollationConnection is the name for collation_connection system variable.
CollationDatabase is the name for collation_database system variable.
Default TiDB system variable values.
Default TiDB system variable values.
Default TiDB system variable values.
Default TiDB system variable values.
Default TiDB system variable values.
Default TiDB system variable values.
Default TiDB system variable values.
Default TiDB system variable values.
Default TiDB system variable values.
Default TiDB system variable values.
Default TiDB system variable values.
32 GiB.
Default TiDB system variable values.
Default TiDB system variable values.
Default TiDB system variable values.
Default TiDB system variable values.
special session variables.
ScopeGlobal means the system variable can be changed globally.
ScopeNone means the system variable can not be changed dynamically.
ScopeSession means the system variable can only be changed in current session.
special session variables.
tidb_batch_delete is used to enable/disable auto-split delete data.
tidb_batch_insert is used to enable/disable auto-split insert data.
tidb_build_stats_concurrency is used to speed up the ANALYZE statement, when a table has multiple indices, those indices can be scanned concurrently, with the cost of higher system performance impact.
tidb_config is a read-only variable that shows the config of the current server.
TiDBCurrentTS is used to get the current transaction timestamp.
tidb_distsql_scan_concurrency is used to set the concurrency of a distsql scan task.
tidb_dml_batch_size is used to split the insert/delete data into small batches.
tidb_general_log is used to log every query in the server in info level.
tidb_import_data is used for loading data from a dump file, to speed up the loading process.
tidb_index_join_batch_size is used to set the batch size of a index lookup join.
tidb_index_lookup_concurrency is used for index lookup executor.
tidb_index_lookup_size is used for index lookup executor.
tidb_index_serial_scan_concurrency is used for controlling the concurrency of index scan operation when we need to keep the data output order the same as the order of index data.
tidb_max_chunk_capacity is used to control the max chunk size during query execution.
tidb_mem_threshold is used to control the memory usage warning threshold in Byte of an executor during query execution.
tidb_opt_agg_push_down is used to endable/disable the optimizer rule of aggregation push down.
tidb_opt_insubquery_unfold is used to enable/disable the optimizer rule of in subquery unfold.
tidb_skip_utf8_check skips the UTF8 validate process, validate UTF8 has performance cost, if we can make sure the input string values are valid, we can skip the check.
tidb_snapshot is used for reading history data, the default value is empty string.
special session variables.
special session variables.
# Variables
DefaultStatusVarScopeFlag is the default scope of status variables.
Error instances.
Variable errors.
Variable errors.
Error instances.
Variable errors.
Process global variables.
SetNamesVariables is the system variable names related to set names statements.
SynonymsSysVariables is synonyms of system variables.
SysVars is global sys vars map.
Variable errors.
Variable errors.
# Structs
RetryInfo saves retry information.
SessionVars is to handle user-defined or global variables in the current session.
StatusVal is the value of the corresponding status variable.
SysVar is for system variable.
TableDelta stands for the changed count for one table.
TransactionContext is used to store variables that has transaction scope.
WriteStmtBufs can be used by insert/replace/delete/update statement.
# Interfaces
GlobalVarAccessor is the interface for accessing global scope system and status variables.
Statistics is the interface of statistics.
# Type aliases
ScopeFlag is for system variable whether can be changed in global/session dynamically or not.