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/******************************************************
Transaction undo log
(c) 1996 Innobase Oy
Created 3/26/1996 Heikki Tuuri
*******************************************************/
#include "data0type.h"
/***************************************************************************
Builds a roll pointer dulint. */
UNIV_INLINE
dulint
trx_undo_build_roll_ptr(
/*====================*/
/* out: roll pointer */
ibool is_insert, /* in: TRUE if insert undo log */
ulint rseg_id, /* in: rollback segment id */
ulint page_no, /* in: page number */
ulint offset) /* in: offset of the undo entry within page */
{
ut_ad(DATA_ROLL_PTR_LEN == 7);
ut_ad(rseg_id < 128);
return(ut_dulint_create(is_insert * 128 * 256 * 256
+ rseg_id * 256 * 256
+ (page_no / 256) / 256,
(page_no % (256 * 256)) * 256 * 256
+ offset));
}
/***************************************************************************
Decodes a roll pointer dulint. */
UNIV_INLINE
void
trx_undo_decode_roll_ptr(
/*=====================*/
dulint roll_ptr, /* in: roll pointer */
ibool* is_insert, /* out: TRUE if insert undo log */
ulint* rseg_id, /* out: rollback segment id */
ulint* page_no, /* out: page number */
ulint* offset) /* out: offset of the undo entry within page */
{
ulint low;
ulint high;
ut_ad(DATA_ROLL_PTR_LEN == 7);
ut_ad(TRUE == 1);
high = ut_dulint_get_high(roll_ptr);
low = ut_dulint_get_low(roll_ptr);
*offset = low % (256 * 256);
*is_insert = high / (256 * 256 * 128); /* TRUE == 1 */
*rseg_id = (high / (256 * 256)) % 128;
*page_no = (high % (256 * 256)) * 256 * 256
+ (low / 256) / 256;
}
/***************************************************************************
Returns TRUE if the roll pointer is of the insert type. */
UNIV_INLINE
ibool
trx_undo_roll_ptr_is_insert(
/*========================*/
/* out: TRUE if insert undo log */
dulint roll_ptr) /* in: roll pointer */
{
ulint high;
ut_ad(DATA_ROLL_PTR_LEN == 7);
ut_ad(TRUE == 1);
high = ut_dulint_get_high(roll_ptr);
return(high / (256 * 256 * 128));
}
/*********************************************************************
Writes a roll ptr to an index page. In case that the size changes in
some future version, this function should be used instead of
mach_write_... */
UNIV_INLINE
void
trx_write_roll_ptr(
/*===============*/
byte* ptr, /* in: pointer to memory where written */
dulint roll_ptr) /* in: roll ptr */
{
ut_ad(DATA_ROLL_PTR_LEN == 7);
mach_write_to_7(ptr, roll_ptr);
}
/*********************************************************************
Reads a roll ptr from an index page. In case that the roll ptr size
changes in some future version, this function should be used instead of
mach_read_... */
UNIV_INLINE
dulint
trx_read_roll_ptr(
/*==============*/
/* out: roll ptr */
byte* ptr) /* in: pointer to memory from where to read */
{
ut_ad(DATA_ROLL_PTR_LEN == 7);
return(mach_read_from_7(ptr));
}
/**********************************************************************
Gets an undo log page and x-latches it. */
UNIV_INLINE
page_t*
trx_undo_page_get(
/*===============*/
/* out: pointer to page x-latched */
ulint space, /* in: space where placed */
ulint page_no, /* in: page number */
mtr_t* mtr) /* in: mtr */
{
page_t* page;
page = buf_page_get(space, page_no, RW_X_LATCH, mtr);
#ifdef UNIV_SYNC_DEBUG
buf_page_dbg_add_level(page, SYNC_TRX_UNDO_PAGE);
#endif /* UNIV_SYNC_DEBUG */
return(page);
}
/**********************************************************************
Gets an undo log page and s-latches it. */
UNIV_INLINE
page_t*
trx_undo_page_get_s_latched(
/*=========================*/
/* out: pointer to page s-latched */
ulint space, /* in: space where placed */
ulint page_no, /* in: page number */
mtr_t* mtr) /* in: mtr */
{
page_t* page;
page = buf_page_get(space, page_no, RW_S_LATCH, mtr);
#ifdef UNIV_SYNC_DEBUG
buf_page_dbg_add_level(page, SYNC_TRX_UNDO_PAGE);
#endif /* UNIV_SYNC_DEBUG */
return(page);
}
/**********************************************************************
Returns the start offset of the undo log records of the specified undo
log on the page. */
UNIV_INLINE
ulint
trx_undo_page_get_start(
/*====================*/
/* out: start offset */
page_t* undo_page,/* in: undo log page */
ulint page_no,/* in: undo log header page number */
ulint offset) /* in: undo log header offset on page */
{
ulint start;
if (page_no == buf_frame_get_page_no(undo_page)) {
start = mach_read_from_2(offset + undo_page
+ TRX_UNDO_LOG_START);
} else {
start = TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_HDR_SIZE;
}
return(start);
}
/**********************************************************************
Returns the end offset of the undo log records of the specified undo
log on the page. */
UNIV_INLINE
ulint
trx_undo_page_get_end(
/*==================*/
/* out: end offset */
page_t* undo_page,/* in: undo log page */
ulint page_no,/* in: undo log header page number */
ulint offset) /* in: undo log header offset on page */
{
trx_ulogf_t* log_hdr;
ulint end;
if (page_no == buf_frame_get_page_no(undo_page)) {
log_hdr = undo_page + offset;
end = mach_read_from_2(log_hdr + TRX_UNDO_NEXT_LOG);
if (end == 0) {
end = mach_read_from_2(undo_page + TRX_UNDO_PAGE_HDR
+ TRX_UNDO_PAGE_FREE);
}
} else {
end = mach_read_from_2(undo_page + TRX_UNDO_PAGE_HDR
+ TRX_UNDO_PAGE_FREE);
}
return(end);
}
/**********************************************************************
Returns the previous undo record on the page in the specified log, or
NULL if none exists. */
UNIV_INLINE
trx_undo_rec_t*
trx_undo_page_get_prev_rec(
/*=======================*/
/* out: pointer to record, NULL if none */
trx_undo_rec_t* rec, /* in: undo log record */
ulint page_no,/* in: undo log header page number */
ulint offset) /* in: undo log header offset on page */
{
page_t* undo_page;
ulint start;
undo_page = buf_frame_align(rec);
start = trx_undo_page_get_start(undo_page, page_no, offset);
if (start + undo_page == rec) {
return(NULL);
}
return(undo_page + mach_read_from_2(rec - 2));
}
/**********************************************************************
Returns the next undo log record on the page in the specified log, or
NULL if none exists. */
UNIV_INLINE
trx_undo_rec_t*
trx_undo_page_get_next_rec(
/*=======================*/
/* out: pointer to record, NULL if none */
trx_undo_rec_t* rec, /* in: undo log record */
ulint page_no,/* in: undo log header page number */
ulint offset) /* in: undo log header offset on page */
{
page_t* undo_page;
ulint end;
ulint next;
undo_page = buf_frame_align(rec);
end = trx_undo_page_get_end(undo_page, page_no, offset);
next = mach_read_from_2(rec);
if (next == end) {
return(NULL);
}
return(undo_page + next);
}
/**********************************************************************
Returns the last undo record on the page in the specified undo log, or
NULL if none exists. */
UNIV_INLINE
trx_undo_rec_t*
trx_undo_page_get_last_rec(
/*=======================*/
/* out: pointer to record, NULL if none */
page_t* undo_page,/* in: undo log page */
ulint page_no,/* in: undo log header page number */
ulint offset) /* in: undo log header offset on page */
{
ulint start;
ulint end;
start = trx_undo_page_get_start(undo_page, page_no, offset);
end = trx_undo_page_get_end(undo_page, page_no, offset);
if (start == end) {
return(NULL);
}
return(undo_page + mach_read_from_2(undo_page + end - 2));
}
/**********************************************************************
Returns the first undo record on the page in the specified undo log, or
NULL if none exists. */
UNIV_INLINE
trx_undo_rec_t*
trx_undo_page_get_first_rec(
/*========================*/
/* out: pointer to record, NULL if none */
page_t* undo_page,/* in: undo log page */
ulint page_no,/* in: undo log header page number */
ulint offset) /* in: undo log header offset on page */
{
ulint start;
ulint end;
start = trx_undo_page_get_start(undo_page, page_no, offset);
end = trx_undo_page_get_end(undo_page, page_no, offset);
if (start == end) {
return(NULL);
}
return(undo_page + start);
}
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