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Detailed revision comments: r6613 | inaam | 2010-02-09 20:23:09 +0200 (Tue, 09 Feb 2010) | 11 lines branches/5.1: Fix Bug #38901 InnoDB logs error repeatedly when trying to load page into buffer pool In buf_page_get_gen() if we are unable to read a page (because of corruption or some other reason) we keep on retrying. This fills up error log with millions of entries in no time and we'd eventually run out of disk space. This patch limits the number of attempts that we make (currently set to 100) and after that we abort with a message. rb://241 Approved by: Heikki
102 lines
4.2 KiB
C
102 lines
4.2 KiB
C
/******************************************************
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The database buffer read
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(c) 1995 Innobase Oy
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Created 11/5/1995 Heikki Tuuri
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*******************************************************/
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#ifndef buf0rea_h
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#define buf0rea_h
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#include "univ.i"
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#include "buf0types.h"
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/************************************************************************
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High-level function which reads a page asynchronously from a file to the
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buffer buf_pool if it is not already there. Sets the io_fix flag and sets
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an exclusive lock on the buffer frame. The flag is cleared and the x-lock
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released by the i/o-handler thread. Does a random read-ahead if it seems
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sensible. */
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ibool
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buf_read_page(
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/*==========*/
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/* out: TRUE if success, FALSE otherwise */
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ulint space, /* in: space id */
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ulint offset);/* in: page number */
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/************************************************************************
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Applies linear read-ahead if in the buf_pool the page is a border page of
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a linear read-ahead area and all the pages in the area have been accessed.
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Does not read any page if the read-ahead mechanism is not activated. Note
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that the the algorithm looks at the 'natural' adjacent successor and
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predecessor of the page, which on the leaf level of a B-tree are the next
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and previous page in the chain of leaves. To know these, the page specified
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in (space, offset) must already be present in the buf_pool. Thus, the
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natural way to use this function is to call it when a page in the buf_pool
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is accessed the first time, calling this function just after it has been
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bufferfixed.
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NOTE 1: as this function looks at the natural predecessor and successor
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fields on the page, what happens, if these are not initialized to any
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sensible value? No problem, before applying read-ahead we check that the
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area to read is within the span of the space, if not, read-ahead is not
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applied. An uninitialized value may result in a useless read operation, but
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only very improbably.
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NOTE 2: the calling thread may own latches on pages: to avoid deadlocks this
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function must be written such that it cannot end up waiting for these
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latches!
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NOTE 3: the calling thread must want access to the page given: this rule is
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set to prevent unintended read-aheads performed by ibuf routines, a situation
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which could result in a deadlock if the OS does not support asynchronous io. */
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ulint
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buf_read_ahead_linear(
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/*==================*/
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/* out: number of page read requests issued */
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ulint space, /* in: space id */
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ulint offset);/* in: page number of a page; NOTE: the current thread
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must want access to this page (see NOTE 3 above) */
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/************************************************************************
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Issues read requests for pages which the ibuf module wants to read in, in
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order to contract the insert buffer tree. Technically, this function is like
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a read-ahead function. */
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void
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buf_read_ibuf_merge_pages(
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/*======================*/
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ibool sync, /* in: TRUE if the caller wants this function
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to wait for the highest address page to get
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read in, before this function returns */
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ulint* space_ids, /* in: array of space ids */
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ib_longlong* space_versions,/* in: the spaces must have this version
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number (timestamp), otherwise we discard the
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read; we use this to cancel reads if
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DISCARD + IMPORT may have changed the
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tablespace size */
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ulint* page_nos, /* in: array of page numbers to read, with the
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highest page number the last in the array */
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ulint n_stored); /* in: number of page numbers in the array */
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/************************************************************************
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Issues read requests for pages which recovery wants to read in. */
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void
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buf_read_recv_pages(
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/*================*/
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ibool sync, /* in: TRUE if the caller wants this function
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to wait for the highest address page to get
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read in, before this function returns */
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ulint space, /* in: space id */
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ulint* page_nos, /* in: array of page numbers to read, with the
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highest page number the last in the array */
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ulint n_stored); /* in: number of page numbers in the array */
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/* The size in pages of the area which the read-ahead algorithms read if
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invoked */
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#define BUF_READ_AHEAD_AREA \
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ut_min(64, ut_2_power_up(buf_pool->curr_size / 32))
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/* Modes used in read-ahead */
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#define BUF_READ_IBUF_PAGES_ONLY 131
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#define BUF_READ_ANY_PAGE 132
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#endif
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