mariadb/extra/mariabackup/read_filt.cc
Marko Mäkelä 8c71c6aa8b MDEV-12548 Initial implementation of Mariabackup for MariaDB 10.2
InnoDB I/O and buffer pool interfaces and the redo log format
have been changed between MariaDB 10.1 and 10.2, and the backup
code has to be adjusted accordingly.

The code has been simplified, and many memory leaks have been fixed.
Instead of the file name xtrabackup_logfile, the file name ib_logfile0
is being used for the copy of the redo log. Unnecessary InnoDB startup and
shutdown and some unnecessary threads have been removed.

Some help was provided by Vladislav Vaintroub.

Parameters have been cleaned up and aligned with those of MariaDB 10.2.

The --dbug option has been added, so that in debug builds,
--dbug=d,ib_log can be specified to enable diagnostic messages
for processing redo log entries.

By default, innodb_doublewrite=OFF, so that --prepare works faster.
If more crash-safety for --prepare is needed, double buffering
can be enabled.

The parameter innodb_log_checksums=OFF can be used to ignore redo log
checksums in --backup.

Some messages have been cleaned up.
Unless --export is specified, Mariabackup will not deal with undo log.
The InnoDB mini-transaction redo log is not only about user-level
transactions; it is actually about mini-transactions. To avoid confusion,
call it the redo log, not transaction log.

We disable any undo log processing in --prepare.

Because MariaDB 10.2 supports indexed virtual columns, the
undo log processing would need to be able to evaluate virtual column
expressions. To reduce the amount of code dependencies, we will not
process any undo log in prepare.

This means that the --export option must be disabled for now.

This also means that the following options are redundant
and have been removed:
	xtrabackup --apply-log-only
	innobackupex --redo-only

In addition to disabling any undo log processing, we will disable any
further changes to data pages during --prepare, including the change
buffer merge. This means that restoring incremental backups should
reliably work even when change buffering is being used on the server.
Because of this, preparing a backup will not generate any further
redo log, and the redo log file can be safely deleted. (If the
--export option is enabled in the future, it must generate redo log
when processing undo logs and buffered changes.)

In --prepare, we cannot easily know if a partial backup was used,
especially when restoring a series of incremental backups. So, we
simply warn about any missing files, and ignore the redo log for them.

FIXME: Enable the --export option.

FIXME: Improve the handling of the MLOG_INDEX_LOAD record, and write
a test that initiates a backup while an ALGORITHM=INPLACE operation
is creating indexes or rebuilding a table. An error should be detected
when preparing the backup.

FIXME: In --incremental --prepare, xtrabackup_apply_delta() should
ensure that if FSP_SIZE is modified, the file size will be adjusted
accordingly.
2017-07-05 11:43:28 +03:00

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6.2 KiB
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/******************************************************
XtraBackup: hot backup tool for InnoDB
(c) 2009-2012 Percona Inc.
Originally Created 3/3/2009 Yasufumi Kinoshita
Written by Alexey Kopytov, Aleksandr Kuzminsky, Stewart Smith, Vadim Tkachenko,
Yasufumi Kinoshita, Ignacio Nin and Baron Schwartz.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*******************************************************/
/* Data file read filter implementation */
#include "read_filt.h"
#include "common.h"
#include "fil_cur.h"
#include "xtrabackup.h"
/****************************************************************//**
Perform read filter context initialization that is common to all read
filters. */
static
void
common_init(
/*========*/
xb_read_filt_ctxt_t* ctxt, /*!<in/out: read filter context */
const xb_fil_cur_t* cursor) /*!<in: file cursor */
{
ctxt->offset = 0;
ctxt->data_file_size = cursor->statinfo.st_size;
ctxt->buffer_capacity = cursor->buf_size;
ctxt->page_size = cursor->page_size;
}
/****************************************************************//**
Initialize the pass-through read filter. */
static
void
rf_pass_through_init(
/*=================*/
xb_read_filt_ctxt_t* ctxt, /*!<in/out: read filter context */
const xb_fil_cur_t* cursor, /*!<in: file cursor */
ulint space_id __attribute__((unused)))
/*!<in: space id we are reading */
{
common_init(ctxt, cursor);
}
/****************************************************************//**
Get the next batch of pages for the pass-through read filter. */
static
void
rf_pass_through_get_next_batch(
/*===========================*/
xb_read_filt_ctxt_t* ctxt, /*!<in/out: read filter
context */
ib_int64_t* read_batch_start, /*!<out: starting read
offset in bytes for the
next batch of pages */
ib_int64_t* read_batch_len) /*!<out: length in
bytes of the next batch
of pages */
{
*read_batch_start = ctxt->offset;
*read_batch_len = ctxt->data_file_size - ctxt->offset;
if (*read_batch_len > (ib_int64_t)ctxt->buffer_capacity) {
*read_batch_len = ctxt->buffer_capacity;
}
ctxt->offset += *read_batch_len;
}
/****************************************************************//**
Deinitialize the pass-through read filter. */
static
void
rf_pass_through_deinit(
/*===================*/
xb_read_filt_ctxt_t* ctxt __attribute__((unused)))
/*!<in: read filter context */
{
}
/****************************************************************//**
Initialize the changed page bitmap-based read filter. Assumes that
the bitmap is already set up in changed_page_bitmap. */
static
void
rf_bitmap_init(
/*===========*/
xb_read_filt_ctxt_t* ctxt, /*!<in/out: read filter
context */
const xb_fil_cur_t* cursor, /*!<in: read cursor */
ulint space_id) /*!<in: space id */
{
common_init(ctxt, cursor);
ctxt->bitmap_range = xb_page_bitmap_range_init(changed_page_bitmap,
space_id);
ctxt->filter_batch_end = 0;
}
/****************************************************************//**
Get the next batch of pages for the bitmap read filter. */
static
void
rf_bitmap_get_next_batch(
/*=====================*/
xb_read_filt_ctxt_t* ctxt, /*!<in/out: read filter
context */
ib_int64_t* read_batch_start, /*!<out: starting read
offset in bytes for the
next batch of pages */
ib_int64_t* read_batch_len) /*!<out: length in
bytes of the next batch
of pages */
{
ulint start_page_id;
const ulint page_size = ctxt->page_size.physical();
start_page_id = (ulint)(ctxt->offset / page_size);
xb_a (ctxt->offset % page_size == 0);
if (start_page_id == ctxt->filter_batch_end) {
/* Used up all the previous bitmap range, get some more */
ulint next_page_id;
/* Find the next changed page using the bitmap */
next_page_id = xb_page_bitmap_range_get_next_bit
(ctxt->bitmap_range, TRUE);
if (next_page_id == ULINT_UNDEFINED) {
*read_batch_len = 0;
return;
}
ctxt->offset = next_page_id * page_size;
/* Find the end of the current changed page block by searching
for the next cleared bitmap bit */
ctxt->filter_batch_end
= xb_page_bitmap_range_get_next_bit(ctxt->bitmap_range,
FALSE);
xb_a(next_page_id < ctxt->filter_batch_end);
}
*read_batch_start = ctxt->offset;
if (ctxt->filter_batch_end == ULINT_UNDEFINED) {
/* No more cleared bits in the bitmap, need to copy all the
remaining pages. */
*read_batch_len = ctxt->data_file_size - ctxt->offset;
} else {
*read_batch_len = ctxt->filter_batch_end * page_size
- ctxt->offset;
}
/* If the page block is larger than the buffer capacity, limit it to
buffer capacity. The subsequent invocations will continue returning
the current block in buffer-sized pieces until ctxt->filter_batch_end
is reached, trigerring the next bitmap query. */
if (*read_batch_len > (ib_int64_t)ctxt->buffer_capacity) {
*read_batch_len = ctxt->buffer_capacity;
}
ctxt->offset += *read_batch_len;
xb_a (ctxt->offset % page_size == 0);
xb_a (*read_batch_start % page_size == 0);
xb_a (*read_batch_len % page_size == 0);
}
/****************************************************************//**
Deinitialize the changed page bitmap-based read filter. */
static
void
rf_bitmap_deinit(
/*=============*/
xb_read_filt_ctxt_t* ctxt) /*!<in/out: read filter context */
{
xb_page_bitmap_range_deinit(ctxt->bitmap_range);
}
/* The pass-through read filter */
xb_read_filt_t rf_pass_through = {
&rf_pass_through_init,
&rf_pass_through_get_next_batch,
&rf_pass_through_deinit
};
/* The changed page bitmap-based read filter */
xb_read_filt_t rf_bitmap = {
&rf_bitmap_init,
&rf_bitmap_get_next_batch,
&rf_bitmap_deinit
};