cs::util::ColumnFilterInboundFunctionalIndexes Class Reference

One use case for filtering relates to hidden generated columns. More...

#include <column_filter_inbound_func_indexes.h>

Inheritance diagram for cs::util::ColumnFilterInboundFunctionalIndexes:

Static Public Member Functions
static bool	is_filter_needed (THD const &thd, TABLE *table, table_def const *tabledef)
	Is this filter needed given context passed in the parameters. More...

Private Member Functions
bool	filter_column (TABLE const *table, size_t column_index) override

Additional Inherited Members
Public Member Functions inherited from cs::util::ColumnFilter
virtual	~ColumnFilter ()=default

Detailed Description

One use case for filtering relates to hidden generated columns.

These type of columns are used to support functional indexes and are not meant to be replicated nor included in the serialization/deserialization of binlog events. Moreover, since hidden generated columns are always placed at the end of the field set, replication would break for cases where replicas have extra columns, if they were not excluded from replication:

 SOURCE TABLE `t`                REPLICA TABLE `t`
 +----+----+----+------+------+  +----+----+----+-----+------+------+
 | C1 | C2 | C3 | HGC1 | HGC2 |  | C1 | C2 | C3 | EC1 | HGC1 | HGC2 |
 +----+----+----+------+------+  +----+----+----+-----+------+------+

In the above example, the extra column EC1 in the replica will be paired with the hidden generated column HGC1 of the source, if hidden generated columns were to be replicated. With filtering enabled for hidden generated columns, applier will observe the columns as follows:

 SOURCE TABLE `t`                REPLICA TABLE `t`
 +----+----+----+                +----+----+----+-----+
 | C1 | C2 | C3 |                | C1 | C2 | C3 | EC1 |
 +----+----+----+                +----+----+----+-----+

Inbound states we are receiving something from the source and filtering that data.

Member Function Documentation

filter_column()

bool cs::util::ColumnFilterInboundFunctionalIndexes::filter_column ( TABLE const *  table, size_t  column_index  )

overrideprivatevirtual

Implements cs::util::ColumnFilter.

is_filter_needed()

bool cs::util::ColumnFilterInboundFunctionalIndexes::is_filter_needed ( THD const &  thd, TABLE *  table, table_def const *  tabledef  )

static

Is this filter needed given context passed in the parameters.

Parameters

thd	the thread objected associated to filter
table	the table where the columns are being iterated
tabledef	the source table definition if applicable

Returns

true if the filter should be used

false if the filter is not needed

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The documentation for this class was generated from the following files:

• sql/changestreams/misc/column_filters/column_filter_inbound_func_indexes.h
• sql/changestreams/misc/column_filters/column_filter_inbound_func_indexes.cc