This class caches table_paths for materialized tables. More...

Classes
struct	RefPath

Public Member Functions
	MaterializedPathCache (THD *thd)

	MaterializedPathCache (const MaterializedPathCache &)=delete

MaterializedPathCache &	operator= (const MaterializedPathCache &)=delete

AccessPath *	LookupPath (const AccessPath *table_path) const
	Look for a cached MATERIALIZE path matching 'table_path', i.e. More...

void	PutPath (AccessPath materialize_path, const AccessPath table_path)
	Add 'materialize_path' to the cache. More...

Private Attributes
Mem_root_array< RefPath >	m_ref_paths
	MATERIALIZE paths for REF access. More...

AccessPath *	m_table_scan {nullptr}
	MATERIALIZE path for TABLE_SCAN access. More...

Detailed Description

This class caches table_paths for materialized tables.

This is useful if we need to plan the query block twice (the hypergraph optimizer can do so, with and without in2exists predicates), both saving work and avoiding issues when we try to throw away the old items_to_copy for a new (identical) one.

Constructor & Destructor Documentation

◆ MaterializedPathCache() [1/2]

MaterializedPathCache::MaterializedPathCache ( THD * thd )

inlineexplicit

◆ MaterializedPathCache() [2/2]

MaterializedPathCache::MaterializedPathCache ( const MaterializedPathCache & )

delete

Member Function Documentation

◆ LookupPath()

AccessPath * MaterializedPathCache::LookupPath ( const AccessPath * table_path ) const

Look for a cached MATERIALIZE path matching 'table_path', i.e.

one where the table_path has the same type as 'table_path', and use the same key prefix if it is a REF.

◆ operator=()

MaterializedPathCache & MaterializedPathCache::operator= ( const MaterializedPathCache & )

delete

◆ PutPath()

void MaterializedPathCache::PutPath	(	AccessPath *	materialize_path,
		const AccessPath *	table_path
	)

Add 'materialize_path' to the cache.

Use the type (and possible key prefix) of 'table_path' as a key for retrieving it later.

Member Data Documentation

◆ m_ref_paths

Mem_root_array<RefPath> MaterializedPathCache::m_ref_paths

private

MATERIALIZE paths for REF access.

◆ m_table_scan

AccessPath* MaterializedPathCache::m_table_scan {nullptr}