firebird-mirror/src/jrd/tra.h

/*
 *	PROGRAM:	JRD Access Method
 *	MODULE:		tra.h
 *	DESCRIPTION:	Transaction block definitions
 *
 * 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): ______________________________________.
 * 2001.6.25 Claudio Valderrama: add dfw_delete_generator and dfw_delete_udf
 *           to the dfw_t enumeration.
 * 2002.10.29 Nickolay Samofatov: Added support for savepoints
 */

#ifndef JRD_TRA_H
#define JRD_TRA_H

/*
 * TMN: Fix this header! It should include any header it needs
 * to define the types this header uses.
 */

#include "../include/fb_blk.h"
#include "../common/classes/tree.h"
#include "../common/classes/GenericMap.h"
#include "../jrd/exe.h"
#include "../jrd/rpb_chain.h"
#include "../jrd/blb.h" // For bid structure
#include "../jrd/sbm.h" // For bid structure
#include "../jrd/sort.h"

#include "../jrd/DatabaseSnapshot.h"
#include "../jrd/TempSpace.h"

namespace EDS {
class Transaction;
}

namespace Jrd {

class blb;
class Lock;
class jrd_rel;
template <typename T> class vec;
class Savepoint;
class Record;
class VerbAction;
class ArrayField;
class Attachment;
class DeferredWork;
class DeferredJob;
class dsql_opn;
class UserManagement;
class thread_db;


const SLONG MAX_TRA_NUMBER = MAX_SLONG;

// Blobs active in transaction identified by bli_temp_id. Please keep this
// structure small as there can be huge amount of them floating in memory.
struct BlobIndex
{
	ULONG bli_temp_id;
	bool bli_materialized;
	jrd_req* bli_request;
	union
	{
		bid bli_blob_id;		// ID of materialized blob
		blb* bli_blob_object;	// Blob object
	};
    static const ULONG& generate(const void* /*sender*/, const BlobIndex& item)
	{
		return item.bli_temp_id;
    }
	// Empty default constructor to make it behave like POD structure
	BlobIndex() {}
	BlobIndex(ULONG temp_id, blb* blob_object) :
		bli_temp_id(temp_id), bli_materialized(false), bli_request(NULL),
		bli_blob_object(blob_object)
	{ }
};

typedef Firebird::BePlusTree<BlobIndex, ULONG, MemoryPool, BlobIndex> BlobIndexTree;

// Transaction block

const int DEFAULT_LOCK_TIMEOUT = -1; // infinite
const char* const TRA_BLOB_SPACE = "fb_blob_";
const char* const TRA_UNDO_SPACE = "fb_undo_";

class jrd_tra : public pool_alloc<type_tra>
{
public:
	enum wait_t {
		tra_no_wait,
		tra_probe,
		tra_wait
	};

	jrd_tra(MemoryPool* p, Firebird::MemoryStats* parent_stats,
			Attachment* attachment, jrd_tra* outer, size_t length = 0)
	:	tra_attachment(attachment),
		tra_pool(p),
		tra_memory_stats(parent_stats),
		tra_blobs_tree(p),
		tra_blobs(outer ? outer->tra_blobs : &tra_blobs_tree),
		tra_arrays(NULL),
		tra_deferred_job(NULL),
		tra_resources(*p),
		tra_context_vars(*p),
		tra_lock_timeout(DEFAULT_LOCK_TIMEOUT),
		tra_timestamp(Firebird::TimeStamp::getCurrentTimeStamp()),
		tra_stats(*p),
		tra_open_cursors(*p),
		tra_outer(outer),
		tra_transactions(*p),
		tra_sorts(*p),
		tra_blob_space(NULL),
		tra_undo_space(NULL),
		tra_undo_record(NULL),
		tra_user_management(NULL),
		tra_autonomous_pool(NULL),
		tra_autonomous_cnt(0)
	{
		tra_transactions.resize(length);
	}

	~jrd_tra();

	static jrd_tra* create(MemoryPool* pool, Attachment* attachment, jrd_tra* outer, size_t length = 0)
	{
		jrd_tra* const transaction =
			FB_NEW(*pool) jrd_tra(pool, &attachment->att_memory_stats, attachment, outer, length);

		if (!outer)
		{
			pool->setStatsGroup(transaction->tra_memory_stats);
		}

		return transaction;
	}

	static void destroy(Database* const dbb, jrd_tra* const transaction)
	{
		if (transaction)
		{
			if (transaction->tra_outer)
			{
				jrd_tra* outer = transaction->tra_outer;
				MemoryPool* const pool = transaction->tra_pool;
				delete transaction;
				outer->releaseAutonomousPool(pool);
			}
			else
			{
				MemoryPool* const pool = transaction->tra_pool;
				Firebird::MemoryStats temp_stats;
				pool->setStatsGroup(temp_stats);
				delete transaction;
				dbb->deletePool(pool);
			}
		}
	}

	Attachment* tra_attachment;			// database attachment
	SLONG tra_number;					// transaction number
	SLONG tra_top;						// highest transaction in snapshot
	SLONG tra_oldest;					// oldest interesting transaction
	SLONG tra_oldest_active;			// record versions older than this can be
										// gargage-collected by this tx
	SLONG tra_att_oldest_active;		// oldest active transaction in the same attachment
	jrd_tra*	tra_next;				// next transaction in database
	jrd_tra*	tra_sibling;			// next transaction in group
	MemoryPool* const tra_pool;			// pool for transaction
	Firebird::MemoryStats	tra_memory_stats;
	BlobIndexTree tra_blobs_tree;		// list of active blobs
	BlobIndexTree* tra_blobs;			// pointer to actual list of active blobs
	ArrayField*	tra_arrays;				// Linked list of active arrays
	Lock*		tra_lock;				// lock for transaction
	vec<Lock*>*		tra_relation_locks;	// locks for relations
	UInt32Bitmap*	tra_commit_sub_trans;	// commited sub-transactions
	Savepoint*	tra_save_point;			// list of savepoints
	Savepoint*	tra_save_free;			// free savepoints
	SLONG tra_save_point_number;		// next save point number to use
	ULONG tra_flags;
	DeferredJob*	tra_deferred_job;	// work deferred to commit time
	ResourceList tra_resources;			// resource existence list
	Firebird::StringMap tra_context_vars; // Context variables for the transaction
	traRpbList* tra_rpblist;			// active record_param's of given transaction
	UCHAR tra_use_count;				// use count for safe AST delivery
	UCHAR tra_callback_count;			// callback count for 'execute statement'
	SSHORT tra_lock_timeout;			// in seconds, -1 means infinite, 0 means NOWAIT
	ULONG tra_next_blob_id;     		// ID of the previous blob or array created in this transaction
	const Firebird::TimeStamp tra_timestamp; // transaction start time
	jrd_req* tra_requests;				// Doubly linked list of requests active in this transaction
	DatabaseSnapshot* tra_db_snapshot;	// Database state snapshot (for monitoring purposes)
	RuntimeStatistics tra_stats;
	Firebird::Array<dsql_req*> tra_open_cursors;
	jrd_tra* const tra_outer;			// outer transaction of an autonomous transaction
	jrd_req* tra_callback_caller;		// caller request for execute statement
	Firebird::Array<UCHAR> tra_transactions;
	SortOwner tra_sorts;

	EDS::Transaction *tra_ext_common;
	//Transaction *tra_ext_two_phase;

private:
	TempSpace* tra_blob_space;	// temp blob storage
	TempSpace* tra_undo_space;	// undo log storage

	Record* tra_undo_record;	// temporary record used for the undo purposes
	UserManagement* tra_user_management;
	MemoryPool* tra_autonomous_pool;
	USHORT tra_autonomous_cnt;
	static const USHORT TRA_AUTONOMOUS_PER_POOL = 64;

public:
	MemoryPool* getAutonomousPool();
	void releaseAutonomousPool(MemoryPool* toRelease);
	jrd_tra* getOuter();

	SSHORT getLockWait() const
	{
		return -tra_lock_timeout;
	}

	TempSpace* getBlobSpace()
	{
		if (tra_outer)
			return tra_outer->getBlobSpace();

		if (!tra_blob_space)
			tra_blob_space = FB_NEW(*tra_pool) TempSpace(*tra_pool, TRA_BLOB_SPACE);

		return tra_blob_space;
	}

	TempSpace* getUndoSpace()
	{
		if (!tra_undo_space)
		{
			fb_assert(!tra_outer);
			tra_undo_space = FB_NEW(*tra_pool) TempSpace(*tra_pool, TRA_UNDO_SPACE);
		}

		return tra_undo_space;
	}

	Record* getUndoRecord(USHORT length)
	{
		if (!tra_undo_record || tra_undo_record->rec_length < length)
		{
			delete tra_undo_record;
			tra_undo_record = FB_NEW_RPT(*tra_pool, length) Record(*tra_pool);
		}

		memset(tra_undo_record, 0, sizeof(Record) + length);

		return tra_undo_record;
	}

	UserManagement* getUserManagement();
};

// System transaction is always transaction 0.
const SLONG TRA_system_transaction = 0;

// Flag definitions for tra_flags.

const ULONG TRA_system			= 1L;			// system transaction
//const ULONG TRA_update		= 2L;			// update is permitted
const ULONG TRA_prepared		= 4L;			// transaction is in limbo
const ULONG TRA_reconnected		= 8L;			// reconnect in progress
//const ULONG TRA_reserving		= 16L;			// relations explicityly locked
const ULONG TRA_degree3			= 32L;			// serializeable transaction
//const ULONG TRA_committing	= 64L;			// commit in progress
const ULONG TRA_write			= 128L;			// transaction has written
const ULONG TRA_readonly		= 256L;			// transaction is readonly
//const ULONG TRA_nowait		= 512L;			// don't wait on relations, give up
const ULONG TRA_prepare2		= 1024L;		// transaction has updated RDB$TRANSACTIONS
const ULONG TRA_ignore_limbo	= 2048L;		// ignore transactions in limbo
const ULONG TRA_invalidated 	= 4096L;		// transaction invalidated by failed write
const ULONG TRA_deferred_meta 	= 8192L;		// deferred meta work posted
//const ULONG TRA_add_log		= 16384L;		// write ahead log file was added
//const ULONG TRA_delete_log	= 32768L;		// write ahead log file was deleted
const ULONG TRA_read_committed	= 65536L;		// can see latest committed records
const ULONG TRA_autocommit		= 131072L;		// autocommits all updates
const ULONG TRA_perform_autocommit	= 262144L;	// indicates autocommit is necessary
const ULONG TRA_rec_version			= 524288L;	// don't wait for uncommitted versions
const ULONG TRA_restart_requests	= 1048576L;	// restart all requests in attachment
const ULONG TRA_no_auto_undo		= 2097152L;	// don't start a savepoint in TRA_start
const ULONG TRA_precommitted		= 4194304L;	// transaction committed at startup

// flags derived from TPB, see also transaction_options() at tra.cpp
const ULONG TRA_OPTIONS_MASK = (TRA_degree3 | TRA_readonly | TRA_ignore_limbo | TRA_read_committed | 
	TRA_autocommit | TRA_rec_version | TRA_no_auto_undo | TRA_restart_requests);

const int TRA_MASK				= 3;
//const int TRA_BITS_PER_TRANS	= 2;
//const int TRA_TRANS_PER_BYTE	= 4;
const int TRA_SHIFT				= 2;

#define TRANS_SHIFT(number)	(((number) & TRA_MASK) << 1)
#define TRANS_OFFSET(number)	((number) >> TRA_SHIFT)

// Transaction cleanup. If a database is never quiescent, look
// for "dead" active transactions every so often at transaction
// startup

const int TRA_ACTIVE_CLEANUP	= 100;

// Transaction states.  The first four are states found
// in the transaction inventory page; the last two are
// returned internally

const int tra_active		= 0;	// Transaction is active
const int tra_limbo			= 1;
const int tra_dead			= 2;
const int tra_committed		= 3;
const int tra_us			= 4;	// Transaction is us
const int tra_precommitted	= 5;	// Transaction is precommitted

// The highest transaction number possible.  This is 0x7fffffff if SLONG is 32 bits.
//#define MAX_TRA_NUMBER		 (~(1L << (BITS_PER_LONG - 1)))

// Savepoint block

class Savepoint : public pool_alloc<type_sav>
{
public:
	~Savepoint()
	{
		deleteActions(sav_verb_actions);
		deleteActions(sav_verb_free);
	}

	VerbAction*		sav_verb_actions;	// verb action list
	VerbAction*		sav_verb_free;		// free verb actions
	USHORT			sav_verb_count;		// Active verb count
	SLONG			sav_number;			// save point number
	Savepoint*		sav_next;
	USHORT			sav_flags;
	TEXT			sav_name[MAX_SQL_IDENTIFIER_SIZE]; // Savepoint name

private:
	void deleteActions(VerbAction* list);
};

// Savepoint block flags.

const int SAV_trans_level	= 1;	// savepoint was started by TRA_start
const int SAV_force_dfw		= 2;	// DFW is present even if savepoint is empty
const int SAV_user			= 4;	// named user savepoint as opposed to system ones

// Maximum size in bytes of transaction-level savepoint data.
// When transaction-level savepoint gets past this size we drop it and use GC
// mechanisms to clean out changes done in transaction
const IPTR SAV_LARGE		= 1024 * 32;

// Deferred work blocks are used by the meta data handler to keep track
// of work deferred to commit time.  This are usually used to perform
// meta data updates

enum dfw_t {
	dfw_null,
	dfw_create_relation,
	dfw_delete_relation,
	dfw_update_format,
	dfw_create_index,
	dfw_delete_index,
	dfw_compute_security,
	dfw_add_file,
	dfw_add_shadow,
	dfw_delete_shadow,
	dfw_modify_file,
	dfw_erase_file,
	dfw_create_field,
	dfw_delete_field,
	dfw_modify_field,
	dfw_delete_global,
	dfw_delete_rfr,
	dfw_post_event,
	dfw_create_trigger,
	dfw_delete_trigger,
	dfw_modify_trigger,
	//dfw_load_triggers,
	dfw_grant,
	dfw_revoke,
	dfw_scan_relation,
	dfw_create_expression_index,
	dfw_delete_expression_index,
	dfw_create_procedure,
	dfw_modify_procedure,
	dfw_delete_procedure,
	dfw_delete_prm,
	dfw_create_collation,
	dfw_delete_collation,
	dfw_delete_exception,
	//dfw_unlink_file,
	dfw_delete_generator,
	dfw_modify_generator,
	dfw_delete_udf,
	dfw_add_difference,
	dfw_delete_difference,
	dfw_begin_backup,
	dfw_end_backup,
	dfw_user_management,
	dfw_create_generator,

	// deferred works argument types
	dfw_arg_index_name,		// index name for dfw_delete_expression_index, mandatory
	dfw_arg_partner_rel_id,	// partner relation id for dfw_delete_index if index is FK, optional
	dfw_arg_proc_name,		// procedure name for dfw_delete_prm, mandatory
	dfw_arg_force_computed,	// we need to drop dependencies from a field that WAS computed
	dfw_arg_check_blr,		// check if BLR is still compilable
	dfw_arg_rel_name,		// relation name of a trigger
	dfw_arg_trg_type,		// trigger type
	dfw_arg_new_name		// new name
};

// Verb actions

class UndoItem
{
public:
    static const SINT64& generate(const void* /*sender*/, const UndoItem& item)
	{
		return item.number;
    }

	UndoItem() {}

	UndoItem(RecordNumber recordNumber, UCHAR recordFlags)
		: number(recordNumber.getValue()),
		  flags(recordFlags),
		  length(0), offset(0), format(NULL)
	{}

	UndoItem(jrd_tra* transaction, RecordNumber recordNumber, const Record* record, UCHAR recordFlags)
		: number(recordNumber.getValue()),
		  flags(recordFlags),
		  length(record->rec_length),
		  offset(0),
		  format(record->rec_format)
	{
		if (length)
		{
			offset = transaction->getUndoSpace()->allocateSpace(length);
			transaction->getUndoSpace()->write(offset, record->rec_data, length);
		}
	}

	Record* setupRecord(jrd_tra* transaction, UCHAR newFlags = 0)
	{
		flags |= newFlags;

		Record* const record = transaction->getUndoRecord(length);
		record->rec_number.setValue(number);
		record->rec_flags = flags;
		record->rec_length = length;
		record->rec_format = format;

		if (length)
		{
			transaction->getUndoSpace()->read(offset, record->rec_data, length);
		}

		return record;
	}

	void release(jrd_tra* transaction)
	{
		if (length)
		{
			transaction->getUndoSpace()->releaseSpace(offset, length);
			length = 0;
			format = NULL;
		}
	}

private:
	SINT64 number;
	UCHAR flags;
	USHORT length;
	offset_t offset;
	const Format* format;
};

typedef Firebird::BePlusTree<UndoItem, SINT64, MemoryPool, UndoItem> UndoItemTree;

class VerbAction : public pool_alloc<type_vct>
{
public:
	~VerbAction()
	{
		delete vct_records;
		delete vct_undo;
	}

	VerbAction* 	vct_next;		// Next action within verb
	jrd_rel*		vct_relation;	// Relation involved
	RecordBitmap*	vct_records;	// Record involved
	UndoItemTree*	vct_undo;		// Data for undo records
};


inline void Savepoint::deleteActions(VerbAction* list)
{
	while (list)
	{
		VerbAction* next = list->vct_next;
		delete list;
		list = next;
	}
};

} //namespace Jrd

#endif // JRD_TRA_H