mariadb/innobase/include/read0read.h
unknown 2662b59306 Added Innobase to source distribution
Docs/manual.texi:
  Added Innobase documentation
configure.in:
  Incremented version
include/my_base.h:
  Added option for Innobase
myisam/mi_check.c:
  cleanup
mysql-test/t/bdb.test:
  cleanup
mysql-test/t/innobase.test:
  Extended with new tests from bdb.test
mysql-test/t/merge.test:
  Added test of SHOW create
mysys/my_init.c:
  Fix for UNIXWARE 7
scripts/mysql_install_db.sh:
  Always write how to start mysqld
scripts/safe_mysqld.sh:
  Fixed type
sql/ha_innobase.cc:
  Update to new version
sql/ha_innobase.h:
  Update to new version
sql/handler.h:
  Added 'update_table_comment()' and 'append_create_info()'
sql/sql_delete.cc:
  Fixes for Innobase
sql/sql_select.cc:
  Fixes for Innobase
sql/sql_show.cc:
  Append create information (for MERGE tables)
sql/sql_update.cc:
  Fixes for Innobase
2001-02-17 14:19:19 +02:00

92 lines
2.9 KiB
C

/******************************************************
Cursor read
(c) 1997 Innobase Oy
Created 2/16/1997 Heikki Tuuri
*******************************************************/
#ifndef read0read_h
#define read0read_h
#include "univ.i"
#include "ut0byte.h"
#include "ut0lst.h"
#include "trx0trx.h"
#include "read0types.h"
/*************************************************************************
Opens a read view where exactly the transactions serialized before this
point in time are seen in the view. */
read_view_t*
read_view_open_now(
/*===============*/
/* out, own: read view struct */
trx_t* cr_trx, /* in: creating transaction, or NULL */
mem_heap_t* heap); /* in: memory heap from which allocated */
/*************************************************************************
Makes a copy of the oldest existing read view, or opens a new. The view
must be closed with ..._close. */
read_view_t*
read_view_oldest_copy_or_open_new(
/*==============================*/
/* out, own: read view struct */
trx_t* cr_trx, /* in: creating transaction, or NULL */
mem_heap_t* heap); /* in: memory heap from which allocated */
/*************************************************************************
Closes a read view. */
void
read_view_close(
/*============*/
read_view_t* view); /* in: read view */
/*************************************************************************
Checks if a read view sees the specified transaction. */
UNIV_INLINE
ibool
read_view_sees_trx_id(
/*==================*/
/* out: TRUE if sees */
read_view_t* view, /* in: read view */
dulint trx_id); /* in: trx id */
/* Read view lists the trx ids of those transactions for which a consistent
read should not see the modifications to the database. */
struct read_view_struct{
ibool can_be_too_old; /* TRUE if the system has had to purge old
versions which this read view should be able
to access: the read view can bump into the
DB_MISSING_HISTORY error */
dulint low_limit_no; /* The view does not need to see the undo
logs for transactions whose transaction number
is strictly smaller (<) than this value: they
can be removed in purge if not needed by other
views */
dulint low_limit_id; /* The read should not see any transaction
with trx id >= this value */
dulint up_limit_id; /* The read should see all trx ids which
are strictly smaller (<) than this value */
ulint n_trx_ids; /* Number of cells in the trx_ids array */
dulint* trx_ids; /* Additional trx ids which the read should
not see: typically, these are the active
transactions at the time when the read is
serialized, except the reading transaction
itself; the trx ids in this array are in a
descending order */
trx_t* creator; /* Pointer to the creating transaction, or
NULL if used in purge */
UT_LIST_NODE_T(read_view_t) view_list;
/* List of read views in trx_sys */
};
#ifndef UNIV_NONINL
#include "read0read.ic"
#endif
#endif