firebird-mirror/src/jrd/btr.h

/*
 *	PROGRAM:	JRD Access Method
 *	MODULE:		btr.h
 *	DESCRIPTION:	Index walking data structures
 *
 * The contents of this file are subject to the Interbase Public
 * License Version 1.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy
 * of the License at http://www.Inprise.com/IPL.html
 *
 * Software distributed under the License is distributed on an
 * "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express
 * or implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code was created by Inprise Corporation
 * and its predecessors. Portions created by Inprise Corporation are
 * Copyright (C) Inprise Corporation.
 *
 * All Rights Reserved.
 * Contributor(s): ______________________________________.
 *
 * 2002.10.28 Sean Leyne - Code cleanup, removed obsolete "DecOSF" port
 *
 */

#ifndef JRD_BTR_H
#define JRD_BTR_H

#include "../jrd/constants.h"
#include "../common/classes/array.h"
#include "../include/fb_blk.h"

#include "../jrd/err_proto.h"    // Index error types
#include "../jrd/RecordNumber.h"
#include "../jrd/sbm.h"

// 64 turns out not to be enough indexes
// #define MAX_IDX		 64		// that should be plenty of indexes

#define MAX_KEY_LIMIT		(dbb->dbb_page_size / 4)

struct dsc;

namespace Jrd {

class jrd_rel;
class jrd_tra;
template <typename T> class vec;
class jrd_req;
struct temporary_key;
class jrd_tra;
class BtrPageGCLock;

enum idx_null_state {
  idx_nulls_none,
  idx_nulls_some,
  idx_nulls_all
};

// Index descriptor block -- used to hold info from index root page

struct index_desc
{
	SLONG	idx_root;						// Index root
	float	idx_selectivity;				// selectivity of index
	USHORT	idx_id;
	UCHAR	idx_flags;
	UCHAR	idx_runtime_flags;				// flags used at runtime, not stored on disk
	USHORT	idx_primary_index;				// id for primary key partner index
	USHORT	idx_primary_relation;			// id for primary key partner relation
	USHORT	idx_count;						// number of keys
	vec<int>*	idx_foreign_primaries;		// ids for primary/unique indexes with partners
	vec<int>*	idx_foreign_relations;		// ids for foreign key partner relations
	vec<int>*	idx_foreign_indexes;		// ids for foreign key partner indexes
	jrd_nod* idx_expression;				// node tree for indexed expresssion
	dsc		idx_expression_desc;			// descriptor for expression result
	jrd_req* idx_expression_request;		// stored request for expression evaluation
	// This structure should exactly match IRTD structure for current ODS
	struct idx_repeat
	{
		USHORT idx_field;					// field id
		USHORT idx_itype;					// data of field in index
		float idx_selectivity;				// segment selectivity
	} idx_rpt[MAX_INDEX_SEGMENTS];
};

struct IndexDescAlloc : public pool_alloc_rpt<index_desc>
{
	index_desc items[1];
};


const USHORT idx_invalid = USHORT(~0);		// Applies to idx_id as special value

// index types and flags

// See jrd/intl.h for notes on idx_itype and dsc_sub_type considerations
// idx_numeric .. idx_byte_array values are compatible with VMS values

const int idx_numeric		= 0;
const int idx_string		= 1;
// AB: idx_timestamp1 removed
const int idx_byte_array	= 3;
const int idx_metadata		= 4;
const int idx_sql_date		= 5;
const int idx_sql_time		= 6;
const int idx_timestamp2	= 7;
const int idx_numeric2		= 8;	// Introduced for 64-bit Integer support

				   // idx_itype space for future expansion
const int idx_first_intl_string	= 64;	// .. MAX (short) Range of computed key strings

const int idx_offset_intl_range	= (0x7FFF + idx_first_intl_string);

// these flags must match the irt_flags

const int idx_unique		= 1;
const int idx_descending	= 2;
const int idx_in_progress	= 4;
const int idx_foreign		= 8;
const int idx_primary		= 16;
const int idx_expressn		= 32;

// these flags are for idx_runtime_flags

const int idx_plan_dont_use	= 1;	// index is not mentioned in user-specified access plan
const int idx_plan_navigate	= 2;	// plan specifies index to be used for ordering
const int idx_used 			= 4;	// index was in fact selected for retrieval
const int idx_navigate		= 8;	// index was in fact selected for navigation
const int idx_plan_missing	= 16;	// index mentioned in missing clause
const int idx_plan_starts	= 32;	// index mentioned in starts clause
const int idx_used_with_and	= 64;	// marker used in procedure sort_indices
const int idx_marker		= 128;	// marker used in procedure sort_indices

// Index insertion block -- parameter block for index insertions

struct index_insertion
{
	RecordNumber iib_number;		// record number (or lower level page)
	SLONG iib_sibling;				// right sibling page
	index_desc*	iib_descriptor;		// index descriptor
	jrd_rel*	iib_relation;		// relation block
	temporary_key*	iib_key;		// varying string for insertion
	RecordBitmap* iib_duplicates;	// spare bit map of duplicates
	jrd_tra*	iib_transaction;	// insertion transaction
	BtrPageGCLock*	iib_dont_gc_lock;	// lock to prevent removal of splitted page
};


// these flags are for the key_flags

const int key_empty		= 1;	// Key contains empty data / empty string
const int key_all_nulls	= 2;	// All key fields are nulls

// Temporary key block

struct temporary_key
{
	USHORT key_length;
	UCHAR key_data[MAX_KEY + 1];
	UCHAR key_flags;
	USHORT key_null_segment;	// index of first encountered null segment.
		// Evaluated in BTR_key only and used in IDX_create_index for better
		// error diagnostics

	// AB: I don't see the use of multiplying with 2 anymore.
	//UCHAR key_data[MAX_KEY * 2];
		// This needs to be on a SHORT boundary.
		// This is because key_data is complemented as
		// (SSHORT *) if value is negative.
		//  See compress() (JRD/btr.cpp) for more details
};


// Index Sort Record -- fix part of sort record for index fast load

// hvlad: index_sort_record structure is stored in sort scratch file so we
// don't want to grow sort file with padding added by compiler to please
// alignment rules.
#pragma pack(1)
struct index_sort_record
{
	// RecordNumber should be at the first place, because it's used
	// for determing sort by creating index (see idx.cpp)
	SINT64 isr_record_number;
	USHORT isr_key_length;
	USHORT isr_flags;
};
#pragma pack()

const int ISR_secondary	= 1;	// Record is secondary version
const int ISR_null		= 2;	// Record consists of NULL values only



// Index retrieval block -- hold stuff for index retrieval

class IndexRetrieval : public pool_alloc_rpt<jrd_nod*, type_irb>
{
public:
	index_desc irb_desc;		// Index descriptor
	USHORT irb_index;			// Index id
	USHORT irb_generic;			// Flags for generic search
	jrd_rel*	irb_relation;	// Relation for retrieval
	USHORT irb_lower_count;		// Number of segments for retrieval
	USHORT irb_upper_count;		// Number of segments for retrieval
	temporary_key*	irb_key;	// key for equality retrieval
	jrd_nod* irb_value[1];
};

// Flag values for irb_generic
const int irb_partial	= 1;				// Partial match: not all segments or starting of key only
const int irb_starting	= 2;				// Only compute "starting with" key for index segment
const int irb_equality	= 4;				// Probing index for equality match
const int irb_ignore_null_value_key  = 8;	// if lower bound is specified and upper bound unspecified,
											// ignore looking at null value keys
const int irb_descending	= 16;			// Base index uses descending order
const int irb_exclude_lower	= 32;			// exclude lower bound keys while scanning index
const int irb_exclude_upper	= 64;			// exclude upper bound keys while scanning index

// macros used to manipulate btree nodes
#define BTR_SIZE	OFFSETA(Ods::btree_page*, btr_nodes)

#define NEXT_NODE(node)	(btree_nod*)(node->btn_data + node->btn_length)
#define NEXT_NODE_RECNR(node)	(btree_nod*)(node->btn_data + node->btn_length + sizeof(SLONG))

//#define LAST_NODE(page)	(btree_nod*) ((UCHAR*) page + page->btr_length)

//#define NEXT_EXPANDED(xxx,yyy)	(btree_exp*) ((UCHAR*) xxx->btx_data + (yyy)->btn_prefix + (yyy)->btn_length)

typedef Firebird::HalfStaticArray<float, 4> SelectivityList;

} //namespace Jrd

#endif // JRD_BTR_H