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trx0undo.h, trx0undo.c, trx0trx.c:

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Update an obsolete comment about trx commit: we can no longer call trx_undo_update_cleanup_by_discard(), and actually, the idea to call it was erroneous, it cannot work
This commit is contained in:
heikki@hundin.mysql.fi 2004-03-18 14:57:22 +02:00
commit fd15536808
3 changed files with 7 additions and 69 deletions
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14
innobase/include/trx0undo.h
View file

@ -251,20 +251,6 @@ trx_undo_update_cleanup(
page_t* undo_page, /* in: update undo log header page,
x-latched */
mtr_t* mtr); /* in: mtr */
/**************************************************************************
Discards an undo log and puts the segment to the list of cached update undo
log segments. This optimized function is called if there is no need to
keep the update undo log because there exist no read views and the transaction
made no delete markings, which would make purge necessary. We restrict this
to undo logs of size 1 to make things simpler. */
dulint
trx_undo_update_cleanup_by_discard(
/*===============================*/
/* out: log sequence number at which mtr is
committed */
trx_t* trx, /* in: trx owning the update undo log */
mtr_t* mtr); /* in: mtr */
/**********************************************************************
Frees or caches an insert undo log after a transaction commit or rollback.
Knowledge of inserts is not needed after a commit or rollback, therefore

12
innobase/trx/trx0trx.c
View file

@ -701,11 +701,13 @@ trx_commit_off_kernel(
TRX_SYS_MYSQL_MASTER_LOG_INFO, &mtr);
}
/* If we did not take the shortcut, the following call
commits the mini-transaction, making the whole transaction
committed in the file-based world at this log sequence number;
otherwise, we get the commit lsn from the call of
trx_undo_update_cleanup_by_discard above.
/* The following call commits the mini-transaction, making the
whole transaction committed in the file-based world, at this
log sequence number. The transaction becomes 'durable' when
we write the log to disk, but in the logical sense the commit
in the file-based data structures (undo logs etc.) happens
here.
NOTE that transaction numbers, which are assigned only to
transactions with an update undo log, do not necessarily come
in exactly the same order as commit lsn's, if the transactions

50
innobase/trx/trx0undo.c
View file

@ -1673,56 +1673,6 @@ trx_undo_update_cleanup(
}
}
/**************************************************************************
Discards an undo log and puts the segment to the list of cached update undo
log segments. This optimized function is called if there is no need to keep
the update undo log because there exist no read views and the transaction
made no delete markings, which would make purge necessary. We restrict this
to undo logs of size 1 to make things simpler. */
dulint
trx_undo_update_cleanup_by_discard(
/*===============================*/
/* out: log sequence number at which mtr is
committed */
trx_t* trx, /* in: trx owning the update undo log */
mtr_t* mtr) /* in: mtr */
{
trx_rseg_t* rseg;
trx_undo_t* undo;
page_t* undo_page;
undo = trx->update_undo;
rseg = trx->rseg;
#ifdef UNIV_SYNC_DEBUG
ut_ad(mutex_own(&(rseg->mutex)));
ut_ad(mutex_own(&kernel_mutex));
#endif /* UNIV_SYNC_DEBUG */
ut_ad(undo->size == 1);
ut_ad(undo->del_marks == FALSE);
ut_ad(UT_LIST_GET_LEN(trx_sys->view_list) == 1);
/* NOTE: we must hold the kernel mutex, because we must prevent
creation of new read views before mtr gets committed! */
undo_page = trx_undo_page_get(undo->space, undo->hdr_page_no, mtr);
trx_undo_discard_latest_update_undo(undo_page, mtr);
undo->state = TRX_UNDO_CACHED;
UT_LIST_REMOVE(undo_list, rseg->update_undo_list, undo);
trx->update_undo = NULL;
UT_LIST_ADD_FIRST(undo_list, rseg->update_undo_cached, undo);
mtr_commit(mtr);
return(mtr->end_lsn);
}
/**********************************************************************
Frees or caches an insert undo log after a transaction commit or rollback.
Knowledge of inserts is not needed after a commit or rollback, therefore