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MDEV-31875 ROW_FORMAT=COMPRESSED table: InnoDB: ... Only 0 bytes read

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buf_read_ahead_random(), buf_read_ahead_linear(): Avoid read-ahead
of the last page(s) of ROW_FORMAT=COMPRESSED tablespaces that use
a page size of 1024 or 2048 bytes. We invoke os_file_set_size() on
integer multiples of 4096 bytes in order to be compatible with
the requirements of innodb_flush_method=O_DIRECT regardless of the
physical block size of the underlying storage.

This change must be null-merged to MariaDB Server 10.5 and later.
There, out-of-bounds read-ahead should be handled gracefully
by simply discarding the buffer page that had been allocated.

Tested by: Matthias Leich
This commit is contained in:
Marko Mäkelä 2023-08-17 10:31:28 +03:00
parent 34e8585437
commit 44df6f35aa
1 changed files with 30 additions and 1 deletions
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31
storage/innobase/buf/buf0rea.cc
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@ -266,8 +266,24 @@ buf_read_ahead_random(const page_id_t page_id, ulint zip_size, bool ibuf)
* buf_read_ahead_random_area;
if (fil_space_t* space = fil_space_acquire(page_id.space())) {
high = space->max_page_number_for_io(high);
ulint space_size = space->committed_size;
ulint zip_size = space->zip_size();
space->release();
/* Avoid read-ahead of the last page(s) of
small-page-size ROW_FORMAT=COMPRESSED tablespaces,
because fil_space_extend_must_retry() would invoke
os_file_set_size() on integer multiples of 4 KiB. */
switch (UNIV_EXPECT(zip_size, 0)) {
case 1024:
space_size &= ~ulint{3};
break;
case 2048:
space_size &= ~ulint{1};
break;
}
if (high > space_size) {
high = space_size;
}
} else {
return(0);
}
@ -531,7 +547,20 @@ buf_read_ahead_linear(const page_id_t page_id, ulint zip_size, bool ibuf)
if (fil_space_t* space = fil_space_acquire(page_id.space())) {
space_size = space->committed_size;
ulint zip_size = space->zip_size();
space->release();
/* Avoid read-ahead of the last page(s) of
small-page-size ROW_FORMAT=COMPRESSED tablespaces,
because fil_space_extend_must_retry() would invoke
os_file_set_size() on integer multiples of 4 KiB. */
switch (UNIV_EXPECT(zip_size, 0)) {
case 1024:
space_size &= ~ulint{3};
break;
case 2048:
space_size &= ~ulint{1};
break;
}
if (high > space_size) {
/* The area is not whole */