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/******************************************************
Rollback segment
(c) 1996 Innobase Oy
Created 3/26/1996 Heikki Tuuri
*******************************************************/
#include "trx0rseg.h"
#ifdef UNIV_NONINL
#include "trx0rseg.ic"
#endif
#include "trx0undo.h"
#include "fut0lst.h"
#include "srv0srv.h"
#include "trx0purge.h"
/**********************************************************************
Looks for a rollback segment, based on the rollback segment id. */
trx_rseg_t*
trx_rseg_get_on_id(
/*===============*/
/* out: rollback segment */
ulint id) /* in: rollback segment id */
{
trx_rseg_t* rseg;
rseg = UT_LIST_GET_FIRST(trx_sys->rseg_list);
ut_ad(rseg);
while (rseg->id != id) {
rseg = UT_LIST_GET_NEXT(rseg_list, rseg);
ut_ad(rseg);
}
return(rseg);
}
/********************************************************************
Creates a rollback segment header. This function is called only when
a new rollback segment is created in the database. */
ulint
trx_rseg_header_create(
/*===================*/
/* out: page number of the created segment,
FIL_NULL if fail */
ulint space, /* in: space id */
ulint max_size, /* in: max size in pages */
ulint* slot_no, /* out: rseg id == slot number in trx sys */
mtr_t* mtr) /* in: mtr */
{
ulint page_no;
trx_rsegf_t* rsegf;
trx_sysf_t* sys_header;
ulint i;
page_t* page;
ut_ad(mtr);
ut_ad(mutex_own(&kernel_mutex));
ut_ad(mtr_memo_contains(mtr, fil_space_get_latch(space),
MTR_MEMO_X_LOCK));
sys_header = trx_sysf_get(mtr);
*slot_no = trx_sysf_rseg_find_free(mtr);
if (*slot_no == ULINT_UNDEFINED) {
return(FIL_NULL);
}
/* Allocate a new file segment for the rollback segment */
page = fseg_create(space, 0, TRX_RSEG + TRX_RSEG_FSEG_HEADER, mtr);
if (page == NULL) {
/* No space left */
return(FIL_NULL);
}
#ifdef UNIV_SYNC_DEBUG
buf_page_dbg_add_level(page, SYNC_RSEG_HEADER_NEW);
#endif /* UNIV_SYNC_DEBUG */
page_no = buf_frame_get_page_no(page);
/* Get the rollback segment file page */
rsegf = trx_rsegf_get_new(space, page_no, mtr);
/* Initialize max size field */
mlog_write_ulint(rsegf + TRX_RSEG_MAX_SIZE, max_size,
MLOG_4BYTES, mtr);
/* Initialize the history list */
mlog_write_ulint(rsegf + TRX_RSEG_HISTORY_SIZE, 0, MLOG_4BYTES, mtr);
flst_init(rsegf + TRX_RSEG_HISTORY, mtr);
/* Reset the undo log slots */
for (i = 0; i < TRX_RSEG_N_SLOTS; i++) {
trx_rsegf_set_nth_undo(rsegf, i, FIL_NULL, mtr);
}
/* Add the rollback segment info to the free slot in the trx system
header */
trx_sysf_rseg_set_space(sys_header, *slot_no, space, mtr);
trx_sysf_rseg_set_page_no(sys_header, *slot_no, page_no, mtr);
return(page_no);
}
/***************************************************************************
Creates and initializes a rollback segment object. The values for the
fields are read from the header. The object is inserted to the rseg
list of the trx system object and a pointer is inserted in the rseg
array in the trx system object. */
static
trx_rseg_t*
trx_rseg_mem_create(
/*================*/
/* out, own: rollback segment object */
ulint id, /* in: rollback segment id */
ulint space, /* in: space where the segment placed */
ulint page_no, /* in: page number of the segment header */
mtr_t* mtr) /* in: mtr */
{
trx_rsegf_t* rseg_header;
trx_rseg_t* rseg;
trx_ulogf_t* undo_log_hdr;
fil_addr_t node_addr;
ulint sum_of_undo_sizes;
ulint len;
ut_ad(mutex_own(&kernel_mutex));
rseg = mem_alloc(sizeof(trx_rseg_t));
rseg->id = id;
rseg->space = space;
rseg->page_no = page_no;
mutex_create(&rseg->mutex, SYNC_RSEG);
UT_LIST_ADD_LAST(rseg_list, trx_sys->rseg_list, rseg);
trx_sys_set_nth_rseg(trx_sys, id, rseg);
rseg_header = trx_rsegf_get_new(space, page_no, mtr);
rseg->max_size = mtr_read_ulint(rseg_header + TRX_RSEG_MAX_SIZE,
MLOG_4BYTES, mtr);
/* Initialize the undo log lists according to the rseg header */
sum_of_undo_sizes = trx_undo_lists_init(rseg);
rseg->curr_size = mtr_read_ulint(rseg_header + TRX_RSEG_HISTORY_SIZE,
MLOG_4BYTES, mtr)
+ 1 + sum_of_undo_sizes;
len = flst_get_len(rseg_header + TRX_RSEG_HISTORY, mtr);
if (len > 0) {
trx_sys->rseg_history_len += len;
node_addr = trx_purge_get_log_from_hist(
flst_get_last(rseg_header + TRX_RSEG_HISTORY, mtr));
rseg->last_page_no = node_addr.page;
rseg->last_offset = node_addr.boffset;
undo_log_hdr = trx_undo_page_get(rseg->space, node_addr.page,
mtr) + node_addr.boffset;
rseg->last_trx_no = mtr_read_dulint(
undo_log_hdr + TRX_UNDO_TRX_NO, mtr);
rseg->last_del_marks = mtr_read_ulint(
undo_log_hdr + TRX_UNDO_DEL_MARKS, MLOG_2BYTES, mtr);
} else {
rseg->last_page_no = FIL_NULL;
}
return(rseg);
}
/*************************************************************************
Creates the memory copies for rollback segments and initializes the
rseg list and array in trx_sys at a database startup. */
void
trx_rseg_list_and_array_init(
/*=========================*/
trx_sysf_t* sys_header, /* in: trx system header */
mtr_t* mtr) /* in: mtr */
{
ulint i;
ulint page_no;
ulint space;
UT_LIST_INIT(trx_sys->rseg_list);
trx_sys->rseg_history_len = 0;
for (i = 0; i < TRX_SYS_N_RSEGS; i++) {
page_no = trx_sysf_rseg_get_page_no(sys_header, i, mtr);
if (page_no == FIL_NULL) {
trx_sys_set_nth_rseg(trx_sys, i, NULL);
} else {
space = trx_sysf_rseg_get_space(sys_header, i, mtr);
trx_rseg_mem_create(i, space, page_no, mtr);
}
}
}
/********************************************************************
Creates a new rollback segment to the database. */
trx_rseg_t*
trx_rseg_create(
/*============*/
/* out: the created segment object, NULL if
fail */
ulint space, /* in: space id */
ulint max_size, /* in: max size in pages */
ulint* id, /* out: rseg id */
mtr_t* mtr) /* in: mtr */
{
ulint page_no;
trx_rseg_t* rseg;
mtr_x_lock(fil_space_get_latch(space), mtr);
mutex_enter(&kernel_mutex);
page_no = trx_rseg_header_create(space, max_size, id, mtr);
if (page_no == FIL_NULL) {
mutex_exit(&kernel_mutex);
return(NULL);
}
rseg = trx_rseg_mem_create(*id, space, page_no, mtr);
mutex_exit(&kernel_mutex);
return(rseg);
}
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