/********************************************************************//**
Fetches the next undo log record from the history list to purge. It must be
released with the corresponding release function.
@return copy of an undo log record or pointer to trx_purge_dummy_rec,
if the whole undo log can skipped in purge; NULL if none left */
UNIV_INTERN
trx_undo_rec_t*
trx_purge_fetch_next_rec(
/*=====================*/
roll_ptr_t* roll_ptr,/*!< out: roll pointer to undo record */
trx_undo_inf_t** cell, /*!< out: storage cell for the record in the
purge array */
mem_heap_t* heap) /*!< in: memory heap where copied */
{
trx_undo_rec_t* undo_rec;
if (purge_sys->state == TRX_STOP_PURGE) {
trx_purge_truncate_if_arr_empty();
return(NULL);
} else if (!purge_sys->next_stored) {
trx_purge_choose_next_log();
if (!purge_sys->next_stored) {
purge_sys->state = TRX_STOP_PURGE;
trx_purge_truncate_if_arr_empty();
if (srv_print_thread_releases) {
fprintf(stderr,
"Purge: No logs left in the"
" history list; pages handled %lu\n",
(ulong) purge_sys->n_pages_handled);
}
return(NULL);
}
}
if (purge_sys->n_pages_handled >= purge_sys->handle_limit) {
purge_sys->state = TRX_STOP_PURGE;
trx_purge_truncate_if_arr_empty();
return(NULL);
} else if (purge_sys->purge_trx_no >= purge_sys->view->low_limit_no) {
purge_sys->state = TRX_STOP_PURGE;
trx_purge_truncate_if_arr_empty();
return(NULL);
}
/* fprintf(stderr, "Thread %lu purging trx %llu undo record %llu\n",
os_thread_get_curr_id(),
(ullint) purge_sys->purge_trx_no,
(ullint) purge_sys->purge_undo_no); */
*roll_ptr = trx_undo_build_roll_ptr(
FALSE, (purge_sys->rseg)->id, purge_sys->page_no,
purge_sys->offset);
*cell = trx_purge_arr_store_info(
purge_sys->purge_trx_no, purge_sys->purge_undo_no);
ut_ad(purge_sys->purge_trx_no < purge_sys->view->low_limit_no);
/* The following call will advance the stored values of purge_trx_no
and purge_undo_no, therefore we had to store them first */
undo_rec = trx_purge_get_next_rec(heap);
return(undo_rec);
}
trx_undo_rec_t*
trx_purge_fetch_next_rec(
/*=====================*/
/* out: copy of an undo log record or
pointer to the dummy undo log record
&trx_purge_dummy_rec, if the whole undo log
can skipped in purge; NULL if none left */
dulint* roll_ptr,/* out: roll pointer to undo record */
trx_undo_inf_t** cell, /* out: storage cell for the record in the
purge array */
mem_heap_t* heap) /* in: memory heap where copied */
{
trx_undo_rec_t* undo_rec;
mutex_enter(&(purge_sys->mutex));
if (purge_sys->state == TRX_STOP_PURGE) {
trx_purge_truncate_if_arr_empty();
mutex_exit(&(purge_sys->mutex));
return(NULL);
}
if (!purge_sys->next_stored) {
trx_purge_choose_next_log();
if (!purge_sys->next_stored) {
purge_sys->state = TRX_STOP_PURGE;
trx_purge_truncate_if_arr_empty();
if (srv_print_thread_releases) {
fprintf(stderr,
"Purge: No logs left in the"
" history list; pages handled %lu\n",
(ulong) purge_sys->n_pages_handled);
}
mutex_exit(&(purge_sys->mutex));
return(NULL);
}
}
if (purge_sys->n_pages_handled >= purge_sys->handle_limit) {
purge_sys->state = TRX_STOP_PURGE;
trx_purge_truncate_if_arr_empty();
mutex_exit(&(purge_sys->mutex));
return(NULL);
}
if (ut_dulint_cmp(purge_sys->purge_trx_no,
purge_sys->view->low_limit_no) >= 0) {
purge_sys->state = TRX_STOP_PURGE;
trx_purge_truncate_if_arr_empty();
mutex_exit(&(purge_sys->mutex));
return(NULL);
}
/* fprintf(stderr, "Thread %lu purging trx %lu undo record %lu\n",
os_thread_get_curr_id(),
ut_dulint_get_low(purge_sys->purge_trx_no),
ut_dulint_get_low(purge_sys->purge_undo_no)); */
*roll_ptr = trx_undo_build_roll_ptr(FALSE, (purge_sys->rseg)->id,
purge_sys->page_no,
purge_sys->offset);
*cell = trx_purge_arr_store_info(purge_sys->purge_trx_no,
purge_sys->purge_undo_no);
ut_ad(ut_dulint_cmp(purge_sys->purge_trx_no,
(purge_sys->view)->low_limit_no) < 0);
/* The following call will advance the stored values of purge_trx_no
and purge_undo_no, therefore we had to store them first */
undo_rec = trx_purge_get_next_rec(heap);
mutex_exit(&(purge_sys->mutex));
return(undo_rec);
}
