MySQL 9.0.0
Source Code Documentation
btr0types.h File Reference

The index tree general types. More...

#include "univ.i"
#include "page0size.h"
#include "page0types.h"
#include "rem0types.h"
#include "sync0rw.h"
#include "ut0rnd.h"

Go to the source code of this file.

Variables

std::atomic_bool btr_search_enabled
 Is search system enabled. More...
 
ulong btr_ahi_parts
 Number of adaptive hash index partition. More...
 
ut::fast_modulo_t btr_ahi_parts_fast_modulo
 Structure to facilitate fast modulo for number of adaptive hash index partition. More...
 
constexpr uint32_t BTR_EXTERN_FIELD_REF_SIZE = FIELD_REF_SIZE
 The size of a reference to data stored on a different page. More...
 
constexpr uint32_t BTR_EXTERN_LOCAL_STORED_MAX_SIZE
 If the data don't exceed the size, the data are stored locally. More...
 

Detailed Description

The index tree general types.

Created 2/17/1996 Heikki Tuuri

Variable Documentation

◆ btr_ahi_parts

ulong btr_ahi_parts
extern

Number of adaptive hash index partition.

◆ btr_ahi_parts_fast_modulo

ut::fast_modulo_t btr_ahi_parts_fast_modulo
extern

Structure to facilitate fast modulo for number of adaptive hash index partition.

◆ BTR_EXTERN_FIELD_REF_SIZE

constexpr uint32_t BTR_EXTERN_FIELD_REF_SIZE = FIELD_REF_SIZE
constexpr

The size of a reference to data stored on a different page.

The reference is stored at the end of the prefix of the field in the index record.

◆ BTR_EXTERN_LOCAL_STORED_MAX_SIZE

constexpr uint32_t BTR_EXTERN_LOCAL_STORED_MAX_SIZE
constexpr
Initial value:
=
constexpr uint32_t BTR_EXTERN_FIELD_REF_SIZE
The size of a reference to data stored on a different page.
Definition: btr0types.h:66

If the data don't exceed the size, the data are stored locally.

◆ btr_search_enabled

std::atomic_bool btr_search_enabled
extern

Is search system enabled.

Search system is protected by array of latches.

Is search system enabled.

While it is false, the AHI data structures can't have new entries added, they can only be removed. It is changed to false while having all AHI latches X-latched, so any section that adds entries to AHI data structures must have at least one S-latch. All changes to this flag are protected by the btr_search_enable_mutex.