~drizzle-trunk/drizzle/development

/******************************************************

Undo modify of a row

(c) 1997 Innobase Oy

Created 2/27/1997 Heikki Tuuri

*******************************************************/

#include "row0umod.h"

#ifdef UNIV_NONINL

#include "row0umod.ic"

#endif

#include "dict0dict.h"

#include "dict0boot.h"

#include "trx0undo.h"

#include "trx0roll.h"

#include "btr0btr.h"

#include "mach0data.h"

#include "row0undo.h"

#include "row0vers.h"

#include "trx0trx.h"

#include "trx0rec.h"

#include "row0row.h"

#include "row0upd.h"

#include "que0que.h"

#include "log0log.h"

/* Considerations on undoing a modify operation.

(1) Undoing a delete marking: all index records should be found. Some of

them may have delete mark already FALSE, if the delete mark operation was

stopped underway, or if the undo operation ended prematurely because of a

system crash.

(2) Undoing an update of a delete unmarked record: the newer version of

an updated secondary index entry should be removed if no prior version

of the clustered index record requires its existence. Otherwise, it should

be delete marked.

(3) Undoing an update of a delete marked record. In this kind of update a

delete marked clustered index record was delete unmarked and possibly also

some of its fields were changed. Now, it is possible that the delete marked

version has become obsolete at the time the undo is started. */

/***************************************************************

Checks if also the previous version of the clustered index record was

modified or inserted by the same transaction, and its undo number is such

that it should be undone in the same rollback. */

UNIV_INLINE

ibool

row_undo_mod_undo_also_prev_vers(

/*=============================*/

				/* out: TRUE if also previous modify or

				insert of this row should be undone */

	undo_node_t*	node,	/* in: row undo node */

	dulint*		undo_no)/* out: the undo number */

{

	trx_undo_rec_t*	undo_rec;

	trx_t*		trx;

	trx = node->trx;

	if (0 != ut_dulint_cmp(node->new_trx_id, trx->id)) {

		*undo_no = ut_dulint_zero;

		return(FALSE);

	}

	undo_rec = trx_undo_get_undo_rec_low(node->new_roll_ptr, node->heap);

	*undo_no = trx_undo_rec_get_undo_no(undo_rec);

	return(ut_dulint_cmp(trx->roll_limit, *undo_no) <= 0);

}

/***************************************************************

Undoes a modify in a clustered index record. */

static

ulint

row_undo_mod_clust_low(

/*===================*/

				/* out: DB_SUCCESS, DB_FAIL, or error code:

				we may run out of file space */

	undo_node_t*	node,	/* in: row undo node */

	que_thr_t*	thr,	/* in: query thread */

	mtr_t*		mtr,	/* in: mtr */

	ulint		mode)	/* in: BTR_MODIFY_LEAF or BTR_MODIFY_TREE */

{

	big_rec_t*	dummy_big_rec;

	btr_pcur_t*	pcur;

	btr_cur_t*	btr_cur;

	ulint		err;

	ibool		success;

	pcur = &(node->pcur);

	btr_cur = btr_pcur_get_btr_cur(pcur);

	success = btr_pcur_restore_position(mode, pcur, mtr);

	ut_ad(success);

	if (mode == BTR_MODIFY_LEAF) {

		err = btr_cur_optimistic_update(BTR_NO_LOCKING_FLAG

						| BTR_NO_UNDO_LOG_FLAG

						| BTR_KEEP_SYS_FLAG,

						btr_cur, node->update,

						node->cmpl_info, thr, mtr);

	} else {

		ut_ad(mode == BTR_MODIFY_TREE);

		err = btr_cur_pessimistic_update(

			BTR_NO_LOCKING_FLAG

			| BTR_NO_UNDO_LOG_FLAG

			| BTR_KEEP_SYS_FLAG,

			btr_cur, &dummy_big_rec, node->update,

			node->cmpl_info, thr, mtr);

	}

	return(err);

}

/***************************************************************

Removes a clustered index record after undo if possible. */

static

ulint

row_undo_mod_remove_clust_low(

/*==========================*/

				/* out: DB_SUCCESS, DB_FAIL, or error code:

				we may run out of file space */

	undo_node_t*	node,	/* in: row undo node */

	que_thr_t*	thr __attribute__((unused)), /* in: query thread */

	mtr_t*		mtr,	/* in: mtr */

	ulint		mode)	/* in: BTR_MODIFY_LEAF or BTR_MODIFY_TREE */

{

	btr_pcur_t*	pcur;

	btr_cur_t*	btr_cur;

	ulint		err;

	ibool		success;

	pcur = &(node->pcur);

	btr_cur = btr_pcur_get_btr_cur(pcur);

	success = btr_pcur_restore_position(mode, pcur, mtr);

	if (!success) {

		return(DB_SUCCESS);

	}

	/* Find out if we can remove the whole clustered index record */

	if (node->rec_type == TRX_UNDO_UPD_DEL_REC

	    && !row_vers_must_preserve_del_marked(node->new_trx_id, mtr)) {

		/* Ok, we can remove */

	} else {

		return(DB_SUCCESS);

	}

	if (mode == BTR_MODIFY_LEAF) {

		success = btr_cur_optimistic_delete(btr_cur, mtr);

		if (success) {

			err = DB_SUCCESS;

		} else {

			err = DB_FAIL;

		}

	} else {

		ut_ad(mode == BTR_MODIFY_TREE);

		/* Note that since this operation is analogous to purge,

		we can free also inherited externally stored fields:

		hence the last FALSE in the call below */

		btr_cur_pessimistic_delete(&err, FALSE, btr_cur, FALSE, mtr);

		/* The delete operation may fail if we have little

		file space left: TODO: easiest to crash the database

		and restart with more file space */

	}

	return(err);

}

/***************************************************************

Undoes a modify in a clustered index record. Sets also the node state for the

next round of undo. */

static

ulint

row_undo_mod_clust(

/*===============*/

				/* out: DB_SUCCESS or error code: we may run

				out of file space */

	undo_node_t*	node,	/* in: row undo node */

	que_thr_t*	thr)	/* in: query thread */

{

	btr_pcur_t*	pcur;

	mtr_t		mtr;

	ulint		err;

	ibool		success;

	ibool		more_vers;

	dulint		new_undo_no;

	ut_ad(node && thr);

	/* Check if also the previous version of the clustered index record

	should be undone in this same rollback operation */

	more_vers = row_undo_mod_undo_also_prev_vers(node, &new_undo_no);

	pcur = &(node->pcur);

	mtr_start(&mtr);

	/* Try optimistic processing of the record, keeping changes within

	the index page */

	err = row_undo_mod_clust_low(node, thr, &mtr, BTR_MODIFY_LEAF);

	if (err != DB_SUCCESS) {

		btr_pcur_commit_specify_mtr(pcur, &mtr);

		/* We may have to modify tree structure: do a pessimistic

		descent down the index tree */

		mtr_start(&mtr);

		err = row_undo_mod_clust_low(node, thr, &mtr, BTR_MODIFY_TREE);

	}

	btr_pcur_commit_specify_mtr(pcur, &mtr);

	if (err == DB_SUCCESS && node->rec_type == TRX_UNDO_UPD_DEL_REC) {

		mtr_start(&mtr);

		err = row_undo_mod_remove_clust_low(node, thr, &mtr,

						    BTR_MODIFY_LEAF);

		if (err != DB_SUCCESS) {

			btr_pcur_commit_specify_mtr(pcur, &mtr);

			/* We may have to modify tree structure: do a

			pessimistic descent down the index tree */

			mtr_start(&mtr);

			err = row_undo_mod_remove_clust_low(node, thr, &mtr,

							    BTR_MODIFY_TREE);

		}

		btr_pcur_commit_specify_mtr(pcur, &mtr);

	}

	node->state = UNDO_NODE_FETCH_NEXT;

	trx_undo_rec_release(node->trx, node->undo_no);

	if (more_vers && err == DB_SUCCESS) {

		/* Reserve the undo log record to the prior version after

		committing &mtr: this is necessary to comply with the latching

		order, as &mtr may contain the fsp latch which is lower in

		the latch hierarchy than trx->undo_mutex. */

		success = trx_undo_rec_reserve(node->trx, new_undo_no);

		if (success) {

			node->state = UNDO_NODE_PREV_VERS;

		}

	}

	return(err);

}

/***************************************************************

Delete marks or removes a secondary index entry if found. */

static

ulint

row_undo_mod_del_mark_or_remove_sec_low(

/*====================================*/

				/* out: DB_SUCCESS, DB_FAIL, or

				DB_OUT_OF_FILE_SPACE */

	undo_node_t*	node,	/* in: row undo node */

	que_thr_t*	thr,	/* in: query thread */

	dict_index_t*	index,	/* in: index */

	dtuple_t*	entry,	/* in: index entry */

	ulint		mode)	/* in: latch mode BTR_MODIFY_LEAF or

				BTR_MODIFY_TREE */

{

	ibool		found;

	btr_pcur_t	pcur;

	btr_cur_t*	btr_cur;

	ibool		success;

	ibool		old_has;

	ulint		err;

	mtr_t		mtr;

	mtr_t		mtr_vers;

	log_free_check();

	mtr_start(&mtr);

	found = row_search_index_entry(index, entry, mode, &pcur, &mtr);

	btr_cur = btr_pcur_get_btr_cur(&pcur);

	if (!found) {

		/* Not found */

		btr_pcur_close(&pcur);

		mtr_commit(&mtr);

		return(DB_SUCCESS);

	}

	/* We should remove the index record if no prior version of the row,

	which cannot be purged yet, requires its existence. If some requires,

	we should delete mark the record. */

	mtr_start(&mtr_vers);

	success = btr_pcur_restore_position(BTR_SEARCH_LEAF, &(node->pcur),

					    &mtr_vers);

	ut_a(success);

	old_has = row_vers_old_has_index_entry(FALSE,

					       btr_pcur_get_rec(&(node->pcur)),

					       &mtr_vers, index, entry);

	if (old_has) {

		err = btr_cur_del_mark_set_sec_rec(BTR_NO_LOCKING_FLAG,

						   btr_cur, TRUE, thr, &mtr);

		ut_ad(err == DB_SUCCESS);

	} else {

		/* Remove the index record */

		if (mode == BTR_MODIFY_LEAF) {

			success = btr_cur_optimistic_delete(btr_cur, &mtr);

			if (success) {

				err = DB_SUCCESS;

			} else {

				err = DB_FAIL;

			}

		} else {

			ut_ad(mode == BTR_MODIFY_TREE);

			btr_cur_pessimistic_delete(&err, FALSE, btr_cur,

						   TRUE, &mtr);

			/* The delete operation may fail if we have little

			file space left: TODO: easiest to crash the database

			and restart with more file space */

		}

	}

	btr_pcur_commit_specify_mtr(&(node->pcur), &mtr_vers);

	btr_pcur_close(&pcur);

	mtr_commit(&mtr);

	return(err);

}

/***************************************************************

Delete marks or removes a secondary index entry if found.

NOTE that if we updated the fields of a delete-marked secondary index record

so that alphabetically they stayed the same, e.g., 'abc' -> 'aBc', we cannot

return to the original values because we do not know them. But this should

not cause problems because in row0sel.c, in queries we always retrieve the

clustered index record or an earlier version of it, if the secondary index

record through which we do the search is delete-marked. */

static

ulint

row_undo_mod_del_mark_or_remove_sec(

/*================================*/

				/* out: DB_SUCCESS or DB_OUT_OF_FILE_SPACE */

	undo_node_t*	node,	/* in: row undo node */

	que_thr_t*	thr,	/* in: query thread */

	dict_index_t*	index,	/* in: index */

	dtuple_t*	entry)	/* in: index entry */

{

	ulint	err;

	err = row_undo_mod_del_mark_or_remove_sec_low(node, thr, index,

						      entry, BTR_MODIFY_LEAF);

	if (err == DB_SUCCESS) {

		return(err);

	}

	err = row_undo_mod_del_mark_or_remove_sec_low(node, thr, index,

						      entry, BTR_MODIFY_TREE);

	return(err);

}

/***************************************************************

Delete unmarks a secondary index entry which must be found. It might not be

delete-marked at the moment, but it does not harm to unmark it anyway. We also

need to update the fields of the secondary index record if we updated its

fields but alphabetically they stayed the same, e.g., 'abc' -> 'aBc'. */

static

ulint

row_undo_mod_del_unmark_sec_and_undo_update(

/*========================================*/

				/* out: DB_FAIL or DB_SUCCESS or

				DB_OUT_OF_FILE_SPACE */

	ulint		mode,	/* in: search mode: BTR_MODIFY_LEAF or

				BTR_MODIFY_TREE */

	que_thr_t*	thr,	/* in: query thread */

	dict_index_t*	index,	/* in: index */

	dtuple_t*	entry)	/* in: index entry */

{

	mem_heap_t*	heap;

	btr_pcur_t	pcur;

	upd_t*		update;

	ulint		err		= DB_SUCCESS;

	ibool		found;

	big_rec_t*	dummy_big_rec;

	mtr_t		mtr;

	trx_t*		trx		= thr_get_trx(thr);

	log_free_check();

	mtr_start(&mtr);

	found = row_search_index_entry(index, entry, mode, &pcur, &mtr);

	if (!found) {

		fputs("InnoDB: error in sec index entry del undo in\n"

		      "InnoDB: ", stderr);

		dict_index_name_print(stderr, trx, index);

		fputs("\n"

		      "InnoDB: tuple ", stderr);

		dtuple_print(stderr, entry);

		fputs("\n"

		      "InnoDB: record ", stderr);

		rec_print(stderr, btr_pcur_get_rec(&pcur), index);

		putc('\n', stderr);

		trx_print(stderr, trx, 0);

		fputs("\n"

		      "InnoDB: Submit a detailed bug report"

		      " to http://bugs.mysql.com\n", stderr);

	} else {

		btr_cur_t*	btr_cur = btr_pcur_get_btr_cur(&pcur);

		err = btr_cur_del_mark_set_sec_rec(BTR_NO_LOCKING_FLAG,

						   btr_cur, FALSE, thr, &mtr);

		ut_a(err == DB_SUCCESS);

		heap = mem_heap_create(100);

		update = row_upd_build_sec_rec_difference_binary(

			index, entry, btr_cur_get_rec(btr_cur), trx, heap);

		if (upd_get_n_fields(update) == 0) {

			/* Do nothing */

		} else if (mode == BTR_MODIFY_LEAF) {

			/* Try an optimistic updating of the record, keeping

			changes within the page */

			err = btr_cur_optimistic_update(

				BTR_KEEP_SYS_FLAG | BTR_NO_LOCKING_FLAG,

				btr_cur, update, 0, thr, &mtr);

			if (err == DB_OVERFLOW || err == DB_UNDERFLOW) {

				err = DB_FAIL;

			}

		} else {

			ut_a(mode == BTR_MODIFY_TREE);

			err = btr_cur_pessimistic_update(

				BTR_KEEP_SYS_FLAG | BTR_NO_LOCKING_FLAG,

				btr_cur, &dummy_big_rec,

				update, 0, thr, &mtr);

		}

		mem_heap_free(heap);

	}

	btr_pcur_close(&pcur);

	mtr_commit(&mtr);

	return(err);

}

/***************************************************************

Undoes a modify in secondary indexes when undo record type is UPD_DEL. */

static

ulint

row_undo_mod_upd_del_sec(

/*=====================*/

				/* out: DB_SUCCESS or DB_OUT_OF_FILE_SPACE */

	undo_node_t*	node,	/* in: row undo node */

	que_thr_t*	thr)	/* in: query thread */

{

	mem_heap_t*	heap;

	dtuple_t*	entry;

	dict_index_t*	index;

	ulint		err;

	heap = mem_heap_create(1024);

	while (node->index != NULL) {

		index = node->index;

		entry = row_build_index_entry(node->row, index, heap);

		err = row_undo_mod_del_mark_or_remove_sec(node, thr, index,

							  entry);

		if (err != DB_SUCCESS) {

			mem_heap_free(heap);

			return(err);

		}

		node->index = dict_table_get_next_index(node->index);

	}

	mem_heap_free(heap);

	return(DB_SUCCESS);

}

/***************************************************************

Undoes a modify in secondary indexes when undo record type is DEL_MARK. */

static

ulint

row_undo_mod_del_mark_sec(

/*======================*/

				/* out: DB_SUCCESS or DB_OUT_OF_FILE_SPACE */

	undo_node_t*	node,	/* in: row undo node */

	que_thr_t*	thr)	/* in: query thread */

{

	mem_heap_t*	heap;

	dtuple_t*	entry;

	dict_index_t*	index;

	ulint		err;

	heap = mem_heap_create(1024);

	while (node->index != NULL) {

		index = node->index;

		entry = row_build_index_entry(node->row, index, heap);

		err = row_undo_mod_del_unmark_sec_and_undo_update(

			BTR_MODIFY_LEAF, thr, index, entry);

		if (err == DB_FAIL) {

			err = row_undo_mod_del_unmark_sec_and_undo_update(

				BTR_MODIFY_TREE, thr, index, entry);

		}

		if (err != DB_SUCCESS) {

			mem_heap_free(heap);

			return(err);

		}

		node->index = dict_table_get_next_index(node->index);

	}

	mem_heap_free(heap);

	return(DB_SUCCESS);

}

/***************************************************************

Undoes a modify in secondary indexes when undo record type is UPD_EXIST. */

static

ulint

row_undo_mod_upd_exist_sec(

/*=======================*/

				/* out: DB_SUCCESS or DB_OUT_OF_FILE_SPACE */

	undo_node_t*	node,	/* in: row undo node */

	que_thr_t*	thr)	/* in: query thread */

{

	mem_heap_t*	heap;

	dtuple_t*	entry;

	dict_index_t*	index;

	ulint		err;

	if (node->cmpl_info & UPD_NODE_NO_ORD_CHANGE) {

		/* No change in secondary indexes */

		return(DB_SUCCESS);

	}

	heap = mem_heap_create(1024);

	while (node->index != NULL) {

		index = node->index;

		if (row_upd_changes_ord_field_binary(node->row, node->index,

						     node->update)) {

			/* Build the newest version of the index entry */

			entry = row_build_index_entry(node->row, index, heap);

			/* NOTE that if we updated the fields of a

			delete-marked secondary index record so that

			alphabetically they stayed the same, e.g.,

			'abc' -> 'aBc', we cannot return to the original

			values because we do not know them. But this should

			not cause problems because in row0sel.c, in queries

			we always retrieve the clustered index record or an

			earlier version of it, if the secondary index record

			through which we do the search is delete-marked. */

			err = row_undo_mod_del_mark_or_remove_sec(node, thr,

								  index,

								  entry);

			if (err != DB_SUCCESS) {

				mem_heap_free(heap);

				return(err);

			}

			/* We may have to update the delete mark in the

			secondary index record of the previous version of

			the row. We also need to update the fields of

			the secondary index record if we updated its fields

			but alphabetically they stayed the same, e.g.,

			'abc' -> 'aBc'. */

			row_upd_index_replace_new_col_vals(entry, index,

							   node->update, NULL);

			err = row_undo_mod_del_unmark_sec_and_undo_update(

				BTR_MODIFY_LEAF, thr, index, entry);

			if (err == DB_FAIL) {

				err = row_undo_mod_del_unmark_sec_and_undo_update(

					BTR_MODIFY_TREE, thr, index, entry);

			}

			if (err != DB_SUCCESS) {

				mem_heap_free(heap);

				return(err);

			}

		}

		node->index = dict_table_get_next_index(node->index);

	}

	mem_heap_free(heap);

	return(DB_SUCCESS);

}

/***************************************************************

Parses the row reference and other info in a modify undo log record. */

static

void

row_undo_mod_parse_undo_rec(

/*========================*/

	undo_node_t*	node,	/* in: row undo node */

	que_thr_t*	thr)	/* in: query thread */

{

	dict_index_t*	clust_index;

	byte*		ptr;

	dulint		undo_no;

	dulint		table_id;

	dulint		trx_id;

	dulint		roll_ptr;

	ulint		info_bits;

	ulint		type;

	ulint		cmpl_info;

	ibool		dummy_extern;

	trx_t*		trx;

	ut_ad(node && thr);

	trx = thr_get_trx(thr);

	ptr = trx_undo_rec_get_pars(node->undo_rec, &type, &cmpl_info,

				    &dummy_extern, &undo_no, &table_id);

	node->rec_type = type;

	node->table = dict_table_get_on_id(table_id, trx);

	/* TODO: other fixes associated with DROP TABLE + rollback in the

	same table by another user */

	if (node->table == NULL) {

		/* Table was dropped */

		return;

	}

	if (node->table->ibd_file_missing) {

		/* We skip undo operations to missing .ibd files */

		node->table = NULL;

		return;

	}

	clust_index = dict_table_get_first_index(node->table);

	ptr = trx_undo_update_rec_get_sys_cols(ptr, &trx_id, &roll_ptr,

					       &info_bits);

	ptr = trx_undo_rec_get_row_ref(ptr, clust_index, &(node->ref),

				       node->heap);

	trx_undo_update_rec_get_update(ptr, clust_index, type, trx_id,

				       roll_ptr, info_bits, trx,

				       node->heap, &(node->update));

	node->new_roll_ptr = roll_ptr;

	node->new_trx_id = trx_id;

	node->cmpl_info = cmpl_info;

}

/***************************************************************

Undoes a modify operation on a row of a table. */

ulint

row_undo_mod(

/*=========*/

				/* out: DB_SUCCESS or error code */

	undo_node_t*	node,	/* in: row undo node */

	que_thr_t*	thr)	/* in: query thread */

{

	ibool	found;

	ulint	err;

	ut_ad(node && thr);

	ut_ad(node->state == UNDO_NODE_MODIFY);

	row_undo_mod_parse_undo_rec(node, thr);

	if (node->table == NULL) {

		found = FALSE;

	} else {

		found = row_undo_search_clust_to_pcur(node);

	}

	if (!found) {

		/* It is already undone, or will be undone by another query

		thread, or table was dropped */

		trx_undo_rec_release(node->trx, node->undo_no);

		node->state = UNDO_NODE_FETCH_NEXT;

		return(DB_SUCCESS);

	}

	node->index = dict_table_get_next_index(

		dict_table_get_first_index(node->table));

	if (node->rec_type == TRX_UNDO_UPD_EXIST_REC) {

		err = row_undo_mod_upd_exist_sec(node, thr);

	} else if (node->rec_type == TRX_UNDO_DEL_MARK_REC) {

		err = row_undo_mod_del_mark_sec(node, thr);

	} else {

		ut_ad(node->rec_type == TRX_UNDO_UPD_DEL_REC);

		err = row_undo_mod_upd_del_sec(node, thr);

	}

	if (err != DB_SUCCESS) {

		return(err);

	}

	err = row_undo_mod_clust(node, thr);

	return(err);

}