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84 commits

Author SHA1 Message Date
marko
9d58e3ff99 branches/zip: Improve the LRU algorithm with a separate unzip_LRU list of
blocks that contains uncompressed and compressed frames.  This patch was
designed by Heikki and Inaam, implemented by Inaam, and refined and reviewed
by Marko and Sunny.

buf_buddy_n_frames, buf_buddy_min_n_frames, buf_buddy_max_n_frames: Remove.

buf_page_belongs_to_unzip_LRU(): New predicate:
bpage->zip.data && buf_page_get_state(bpage) == BUF_BLOCK_FILE_PAGE.

buf_pool_t, buf_block_t: Add the linked list unzip_LRU.  A block in the
regular LRU list is in unzip_LRU iff buf_page_belongs_to_unzip_LRU() holds.

buf_LRU_free_block(): Add a third return value to refine the case
"cannot free the block".

buf_LRU_search_and_free_block(): Update the documentation to reflect the
implementation.

buf_LRU_stat_t, buf_LRU_stat_cur, buf_LRU_stat_sum, buf_LRU_stat_arr[]:
Statistics for the unzip_LRU algorithm.

buf_LRU_stat_update(): New function: Update the statistics.  Called once
per second by srv_error_monitor_thread().

buf_LRU_validate(): Validate the unzip_LRU list as well.

buf_LRU_evict_from_unzip_LRU(): New predicate: Use the unzip_LRU before
falling back to the regular LRU?

buf_LRU_free_from_unzip_LRU_list(), buf_LRU_free_from_common_LRU_list():
Subfunctions of buf_LRU_search_and_free_block().

buf_LRU_search_and_free_block(): Reimplement.  Try to evict an uncompressed
page from the unzip_LRU list before falling back to evicting an entire block
from the common LRU list.

buf_unzip_LRU_remove_block_if_needed(): New function.

buf_unzip_LRU_add_block(): New function: Add a block to the unzip_LRU list.
2008-03-03 12:48:38 +00:00
marko
aca7dcbeaa branches/zip: Minor fixes.
buf_LRU_old_adjust_len(): Replace a constant ut_ad() with a preprocessor check.

buf_LRU_free_block(): Remove the check for the unlikely case
buf_pool->LRU_old == prev_b in order to simplify the function.
The check was implemented as part of r2306.
2008-02-18 15:43:16 +00:00
marko
d917b27aa8 branches/zip: buf_LRU_free_block(): When freeing the uncompressed page
corresponding to a compressed page, do not flag the block as recently
used, but maintain the position of the control block on the LRU list.
2008-02-16 10:33:15 +00:00
marko
9b9dad7bca branches/zip: buf0lru.c: Minor cleanup.
Use ut_d() in assignments to bpage->in_LRU_list instead of #ifdef UNIV_DEBUG.

buf_LRU_remove_block(): Move an assertion to a more appropriate place.
2008-02-15 11:45:37 +00:00
marko
2c2b06ad75 branches/zip: Introduce UNIV_INTERN, a linkage specifier for InnoDB-global
symbols.  Use it for all definitions of non-static variables and functions.

lexyy.c, make_flex.sh: Declare yylex as UNIV_INTERN, not static.  It is
referenced from pars0grm.c.

Actually, according to
	nm .libs/ha_innodb.so|grep -w '[ABCE-TVXYZ]'
the following symbols are still global:

* The vtable for class ha_innodb
* pars0grm.c: The function yyparse() and the variables yychar, yylval, yynerrs

The required changes to the Bison-generated file pars0grm.c will be addressed
in a separate commit, which will add a script similar to make_flex.sh.

The class ha_innodb is renamed from class ha_innobase by a #define.  Thus,
there will be no clash with the builtin InnoDB.  However, there will be some
overhead for invoking virtual methods of class ha_innodb.  Ideas for making
the vtable hidden are welcome.  -fvisibility=hidden is not available in GCC 3.
2008-02-06 14:17:36 +00:00
marko
473d7c16a9 branches/zip: Introduce the page type code FIL_PAGE_TYPE_ZBLOB2 for
continuation pages containing compressed BLOBs.  The first compressed
BLOB page will be of type FIL_PAGE_TYPE_ZBLOB.
2008-01-24 08:12:02 +00:00
marko
e8574ccb03 branches/zip: buf_LRU_search_and_free_block(): Do not forbid the release
of the buffer pool mutex.  Apparently, it is temporarily released also
in older versions of MySQL/InnoDB for the duration of the
btr_search_drop_page_hash_index() call [in buf_LRU_free_block()].
2008-01-10 12:34:25 +00:00
marko
523a8a0e8d branches/zip: Add instrumentation for prohibiting the release of
the buffer pool mutex.  The instrumentation can be activated by
defining UNIV_DEBUG or UNIV_BUF_DEBUG at compilation time.

buf_pool_mutex_exit_forbidden: New variable.  When this is nonzero,
an assertion will fail in buf_pool_mutex_exit().

buf_pool_mutex_exit_forbid(): Macro for declaring that the buffer pool
mutex must not be released.  Calls may be nested.

buf_pool_mutex_exit_allow(): Macro for declaring that the buffer pool
mutex may be released.  Calls may be nested.

buf_LRU_search_and_free_block(): Prohibit buf_pool_mutex_exit() in the
scope of the function.

buf_LRU_free_block(): Prohibit buf_pool_mutex_exit() in buf_buddy_alloc()
and buf_buddy_free().

buf_LRU_block_remove_hashed_page(): Prohibit buf_pool_mutex_exit()
in buf_buddy_free().
2008-01-10 09:51:57 +00:00
marko
3bb405841f branches/zip: Implement wrappers for all operations on the buffer pool mutex.
buf_pool->mutex: Rename to buf_pool_mutex, so that the wrappers will have
to be used when changes are merged from other source trees.

buf_pool->zip_mutex: Rename to buf_pool_zip_mutex.

buf_pool_mutex_own(), buf_pool_mutex_enter(), buf_pool_mutex_exit():
Wrappers for buf_pool_mutex.
2008-01-10 09:37:13 +00:00
marko
6f306fad26 branches/zip: buf_buddy_alloc(): Assign *lru = TRUE whenever the buffer pool
mutex is temporarily released.

buf_LRU_free_block(), buf_buddy_alloc_clean(): Add an output parameter that
will be assigned TRUE when the buffer pool mutex is released.

This bug was spotted by and fix provided by Sunny.
2007-12-10 09:48:28 +00:00
marko
e00f417abb branches/zip: buf_LRU_block_remove_hashed_page(): Add some Valgrind
instrumentation.
2007-10-31 10:40:41 +00:00
marko
7319444c08 branches/zip: Improve Valgrind instrumentation.
buf_LRU_free_block(): Check that the block descriptor contains valid data.

buf_buddy_relocate(): Check that the source block contains valid data.

buf_page_get_gen(): Do not dereference bpage after calling buf_relocate().
This avoids a bogus Valgrind warning; the memory itself was valid.

buf_page_hash_get(): Check that the returned block descriptor contains
valid data.
2007-10-30 09:27:09 +00:00
marko
372a25240a branches/zip: Improve Valgrind instrumentation.
UNIV_MEM_ASSERT_RW(): New macro, to check that the contents of a memory
area is defined.

UNIV_MEM_ASSERT_W(): New macro, to check that a memory area is writable.

UNIV_MEM_ASSERT_AND_FREE(): New macro, to check that the memory is
writable before declaring it free (unwritable).  This replaces UNIV_MEM_FREE()
in many places.

mem_init_buf(): Declare the memory undefined.

mem_erase_buf(): Declare the memory freed.
2007-09-06 11:36:35 +00:00
marko
1cd528122e branches/zip: buf_LRU_block_free_non_file_page(): Flag block->frame
allocated before overwriting some fields and flagging the frame freed.
Some of the buffer frame may have been flagged freed by the user
(such as mem_heap).
2007-03-28 11:07:28 +00:00
marko
9b861942ac branches/zip: buf_LRU_search_and_free_block(): Do not try to preserve
compressed pages, because doing so would require a call to
buf_buddy_alloc(), which in turn can invoke buf_LRU_get_free_block()
and buf_LRU_search_and_free_block(), potentially infinite recursion.
2007-02-19 14:23:32 +00:00
marko
d56453be8e branches/zip: buf_LRU_search_and_free_block(): Avoid freeing compressed-only
pages when they do not occupy too much of the buffer pool.

buf0buddy.c, buf0buddy.h: Export buf_buddy_n_frames and buf_buddy_min_n_frames.
2007-02-16 09:22:50 +00:00
marko
1a103f0324 branches/zip: buf_LRU_get_free_block(): Add an UNIV_UNLIKELY hint
around zip_size.  zip_size will be 0 most of the time.
2007-02-13 11:21:57 +00:00
marko
eb03297439 branches/zip: buf_page_init_for_read(): Defer the costly calls to
buf_buddy_alloc() until after the block has been found not to exist
in the buffer pool.

buf_buddy_alloc(), buf_buddy_alloc_low(): Make lru an output parameter.
Improve documentation.

buf_page_init_for_read(): Simplify the code.  Check buf_page_hash_get()
again if buf_buddy_alloc() released buf_pool->mutex.
2007-02-08 14:19:55 +00:00
marko
329c469e70 branches/zip: Do not decompress blocks in buf_page_init_for_read(),
but in buf_page_get_gen().  Adjust comments.  This prevents
unnecessary decompression in read-ahead when the compressed block
exists in the buffer pool.

If the block does not exist in the buffer pool, read-ahead will still
allocate an uncompressed page and decompress the block.

Move buf_block_init_low() and buf_zip_decompress() earlier in the file,
because some compilers are unable to inline functions that are defined
after the invocation.

buf_page_get_gen(): Decompress the block if needed.

buf_page_init_for_read(): Do not decompress.
2007-02-07 13:59:43 +00:00
marko
3b5c872916 branches/zip: buf_page_t: Add the in_page_hash and in_zip_hash
for extra validation in UNIV_DEBUG builds.
2007-01-24 10:36:05 +00:00
marko
22147cce7c branches/zip: Fix bugs.
buf_LRU_free_block(): Do not allocate the control block when
a compressed-only page is being freed.

buf_validate(): Note that buf_pool->zip_clean may contain blocks
with io_fix == BUF_IO_READ.
2007-01-18 20:29:35 +00:00
marko
d8536b0de8 branches/zip: Make mutex_own() work with UNIV_DEBUG, without UNIV_SYNC_DEBUG. 2007-01-18 18:29:12 +00:00
marko
fc5428caf3 branches/zip: buf_LRU_free_block(): Allocate a control block for the
compressed page also when freeing an unmodified uncompressed page.
2007-01-18 15:43:59 +00:00
marko
fff329cd3d branches/zip: Remove the fil_space_get_zip_size() call from
buf_page_get_gen().  This saves one mutex operation per block request.

buf_page_get_gen(), various macros and functions: Add parameter zip_size.

btr_node_ptr_get_child(): Add parameter index.

fil_space_get_latch(): Add optional output parameter zip_size.

fil_space_get_zip_size(): Return 0 for space id==0, because the
system tablespace is never compressed.

fsp_header_init(): Remove the parameter zip_size.

ibuf_free_excess_pages(): Remove the parameter zip_size.

trx_rseg_t, trx_undo_t: Add field zip_size.

xdes_lst_get_next(): Remove, unused.
2007-01-18 09:59:00 +00:00
marko
361fe1a5b9 branches/zip: Allow dirty compressed-only blocks to exist in the buffer pool
and to be flushed to disk.

buf_LRU_free_block(): Enable the freeing of uncompressed pages of
compressed tablespaces.

trx_doublewrite->buf_block_arr[]: Change the type from buf_block_t*
to buf_page_t*.

buf_flush_ready_for_flush(): Add debug assertion.

buf_flush_buffered_writes(), buf_flush_try_page(): Support blocks of type
BUF_BLOCK_ZIP_DIRTY.

buf_flush_post_to_doublewrite_buf(), buf_flush_write_block_low():
Change the type of the parameter from buf_block_t* to buf_page_t*.

buf_flush_init_for_writing(): Allow page to be NULL if page_zip_ is non-NULL.
2007-01-16 18:02:49 +00:00
marko
e7b0c68acd branches/zip: Note that b (the newly created control block for the
compressed page) is not protected by block_mutex.  Before releasing
buf_pool->mutex, we can simply assign b->io_fix.  After reacquiring
buf_pool->mutex, we also have to acquire buf_pool->zip_mutex.
2007-01-16 16:39:53 +00:00
marko
13629c137f branches/zip: buf_LRU_free_block(): When preserving the compressed page
of a block, do not release buf_pool->mutex between the time the old control
block is removed from buf_pool->page_hash and the new control block is
added to it.  Prevent operations on the compressed-only block while calling
btr_search_drop_page_hash_index() or page_zip_calc_checksum().

buf_LRU_invalidate_tablespace(): Revert the change done in r1223.
buf_pool->zip_mutex will have been released by
buf_LRU_block_remove_hashed_page() when it returns BUF_BLOCK_ZIP_FREE.
2007-01-16 16:24:47 +00:00
marko
fb8b8e6d5c branches/zip: buf_flush_remove(): buf_page_get_mutex(bpage) must have been
acquired by the caller.

buf_LRU_invalidate_tablespace(): Do not leak buf_pool->zip_mutex when
rescanning the LRU list.
2007-01-16 14:37:40 +00:00
marko
8a6e7d8c91 branches/zip: buf_LRU_free_block(): When freeing the uncompressed page
of a dirty block, relocate the control blocks on buf_pool->flush_list
instead of calling buf_flush_insert_into_flush_list().
2007-01-16 14:11:21 +00:00
marko
71f9cdd62b branches/zip: buf_LRU_block_remove_hashed_page(): When preserving the
compressed page, copy the contents from the uncompressed page if necessary.
2007-01-16 10:24:13 +00:00
marko
34c50ac343 branches/zip: buf_LRU_free_block(): Flag the buffer frame fully initialized
when calling btr_search_drop_page_hash_index() and uninitialized after that.
2007-01-14 20:32:44 +00:00
marko
5637695ad2 branches/zip: Improve Valgrind instrumentation of allocated memory.
UNIV_MEM_FREE(): Declare a memory area free.
UNIV_MEM_ALLOC(): Declare a memory area allocated (but uninitialized).
UNIV_MEM_DESC(): Associate a memory area with a control block.
UNIV_MEM_UNDESC(): Unassociate a control block.

trx_sys_create_doublewrite_buf(): Clear the buffer with memset().

buf_page_init(): Add a bogus UNIV_MEM_VALID(block->frame) to silence
valid warnings about InnoDB data pages containing uninitialized data.

buf_LRU_get_free_only(): Add UNIV_MEM_ALLOC(block->frame).

buf_LRU_get_free_block(): Add UNIV_MEM_DESC(block->page.zip.data, block).

buf_LRU_free_block(): Add UNIV_MEM_DESC(b->zip.data, b) when allocating
a compressed-only control block for a compressed page.

buf_LRU_block_free_non_file_page(): Replace UNIV_MEM_INVALID() with
UNIV_MEM_FREE().

buf_LRU_block_remove_hashed_page(): Add UNIV_MEM_UNDESC(bpage) when
deallocating a compressed-only control block.  Add
UNIV_MEM_INVALID(block->frame).  (The frame should be flagged free
by buf_LRU_block_free_non_file_page() moments later.)

buf0buddy.c: Disable some extra checks in Valgrind-instrumented builds.
Add UNIV_MEM_VALID(), UNIV_MEM_INVALID(), UNIV_MEM_FREE(), UNIV_MEM_ALLOC()
as necessary.
2007-01-12 12:36:40 +00:00
marko
466b2477e4 branches/zip: buf_LRU_invalidate_tablespace(): After freeing a
compressed-only page, restart the scan of the LRU list, because
prev_bpage may have been relocated.

buf_LRU_block_remove_hashed_page(): Note that other compressed pages
or compressed-only blocks may be relocated when freeing a compressed
page or a compressed-only block descriptor.
2007-01-09 15:52:08 +00:00
marko
2b0016ed44 branches/zip: buf_LRU_free_block(): Correct the logic for releasing
dirty uncompressed blocks.  Move the page_zip_validate() call to
a more appropriate place, buf_LRU_block_remove_hashed_page().

buf_LRU_block_remove_hashed_page(): Allow bpage->oldest_modification != 0
for uncompressed pages if there is a compressed page that will be preserved.
Release the mutexes before calling buf_print() and buf_LRU_print().

page_zip_validate(): Remove the assertion containing the
buf_frame_get_page_zip() call.  We might already be holding buf_pool->mutex.
2007-01-09 12:47:15 +00:00
marko
10c92bd7ac branches/zip: buf_buddy_alloc_clean(): Restart the scan after a
successful buf_LRU_free_block().

buf_LRU_free_block(): Note that buf_pool->mutex may be temporarily released.
2007-01-09 12:39:50 +00:00
marko
8af159117e branches/zip: buf_page_t: Introduce the field in_flush_list #ifdef UNIV_DEBUG.
buf_flush_batch(): Remove the local variable "found".
2007-01-09 12:35:42 +00:00
marko
e8d77f6d5a branches/zip: Maintain a valid checksum for compressed-only pages kept in
the buffer pool.

buf_LRU_free_block(): When preserving the compressed page, compute the
checksum.  Also assert page_zip_validate().

buf_zip_decompress(): Add parameter "check" for enabling checksum tests.
Before decompressing a compressed-only page from the buffer pool, verify
the compressed page checksum.
2007-01-08 17:08:57 +00:00
marko
13faf3d3ab branches/zip: buf_LRU_free_block(): Check if the block has been reloaded
to the buffer pool while we were not holding buf_pool->mutex.  If it was,
do not attempt to preserve the compressed page.
2007-01-08 14:58:20 +00:00
marko
14b99876d0 branches/zip: Allow dirty blocks to be relocated. Allow a transition
to BUF_BLOCK_ZIP_DIRTY (discarding the uncompressed page corresponding
to a modified compressed page that has not been flushed to disk).

buf_page_can_relocate(): New function, modelled after
buf_flush_ready_for_replace().

buf_LRU_free_block(): Allow the transition to BUF_BLOCK_ZIP_DIRTY.

buf_flush_insert_into_flush_list(): Make the prototype public.

buf_buddy_relocate(): Remove an unnecessary switch statement.
Use buf_page_can_relocate() instead of buf_flush_ready_for_replace().

buf_page_peek(): Made UNIV_INLINE.

Document UNIV_ZIP_DEBUG.
2007-01-04 21:40:10 +00:00
marko
4861c59c59 branches/zip: Fix two bugs in the relocation of block descriptors.
Improve diagnostics.

buf_buddy_relocate(): Do not assume all small blocks to contain only one
buf_page_t object.  Require an exact size match, as in the case of
compressed pages.

buf_relocate(): Relocate buf_pool->LRU_old if needed.
Validate the LRU list in debug builds.

buf_LRU_block_remove_hashed_page(): Do not overwrite FIL_PAGE_OFFSET
or FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID.  The memory will be invalidated
in debug builds of buf_buddy_free().

buf0buddy.c: Add assertions for not holding buf_pool->zip_mutex.
The calling thread should not be holding any block->mutex, but it might
be too time-consuming to assert against that, even #ifdef UNIV_SYNC_DEBUG.
2007-01-04 15:45:42 +00:00
marko
4b903959da branches/zip: Before calling buf_buddy_alloc() or buf_buddy_free(),
release any block mutexes but hold the buf_pool->mutex.
2007-01-03 15:54:05 +00:00
marko
39e30c0b9b branches/zip: Use the buddy allocator for managing compressed pages.
There is something wrong with the management of compressed-only blocks
(BUF_BLOCK_ZIP_PAGE).  To disable the creation of such blocks, set zip=TRUE
in buf_LRU_block_remove_hashed_page().

buf_LRU_block_remove_hashed_page(): Release buf_pool->zip_mutex when
freeing a compressed-only page and its control block, with buf_buddy_free().
Adapt callers.

buf_LRU_block_free_hashed_page(): Change the parameter type from buf_page_t*
to buf_block_t*.

buf_LRU_free_block(): Move below the definition of buf_LRU_add_block_low().
Allocate block descriptor for compressed-only blocks.

buf_LRU_block_free_non_file_page(): Replace ut_free() with buf_buddy_free().

buf_zip_decompress(): New function, split from buf_page_io_complete().

buf_page_init_for_read(): Do not allocate the compressed page until it is
really needed, to avoid the overhead of the buddy allocator.  Decompress
compressed-only blocks that are needed again.

buf_page_create(): Do not allocate the compressed page until it is
really needed, to avoid the overhead of the buddy allocator.

buf_validate(): Replace some equality tests on the lengths of the LRU
list and the flush lists with greater-or-equal tests, since the counted
numbers do not include control blocks for compressed-only pages.
2007-01-03 13:10:46 +00:00
marko
a687ccdf74 branches/zip: Minor improvements.
buf_LRU_block_remove_hashed_page(): Return the new state of the block.

Only call buf_LRU_block_free_hashed_page()
if buf_LRU_block_remove_hashed_page() did not return BUF_BLOCK_ZIP_FREE,
that is, the control block was not freed.

buf_LRU_insert_zip_clean(): New function, for inserting a compressed-only
block into buf_pool->zip_clean in the LRU order.

buf_LRU_block_remove_hashed_page(), buf_LRU_free_block():
Add the flag "zip" for controlling if the compressed page of an uncompressed
page should be removed.  For now, assume zip==TRUE.

buf_LRU_get_free_block(): Replace the test for UT_LIST_GET_LEN(buf_pool->free)
with a test for the return value of buf_LRU_get_free_only().  Do not
free zip.data, as it must already have been freed.

buf_flush_insert_into_flush_list(), buf_flush_insert_sorted_into_flush_list():
Remove compressed-only blocks from the buf_pool->zip_clean list.

buf_flush_remove(): Restore compressed-only blocks to
the buf_pool->zip_clean list.

buf_page_init_for_read(): Uncompress compressed-only blocks when possible.
Currently, there cannot be any compressed-only blocks in the buffer pool;
they would be inserted by buf_LRU_free_block(bpage, zip=FALSE).
2006-12-15 15:05:18 +00:00
marko
b6711d691e branches/zip: Minor improvements.
buf_flush_remove(): New function, for removing a block from the flush list.
Sliced from buf_flush_write_complete().

buf_page_set_state(): Allow transitions between BUF_BLOCK_ZIP_PAGE
and BUF_BLOCK_ZIP_DIRTY.
2006-12-15 14:47:04 +00:00
marko
2208d25976 branches/zip: Make use of the previously unused state BUF_BLOCK_MEMORY.
buf_LRU_get_free_block(): Document that the block is in the state
BUF_BLOCK_READY_FOR_USE.

buf_block_alloc(): Change the state of the block to BUF_BLOCK_MEMORY
and document it.

Replace those invocations of buf_block_alloc() with
buf_LRU_get_free_block() where the allocated block is used for buffer
pool input and output.  However, temporary copies of B-tree pages
during reorganization are not used for file I/O, and such blocks are
still allocated with buf_block_alloc().
2006-12-13 14:58:54 +00:00
marko
8e3e3d16d3 branches/zip: Implement the whole allocation algorithm of compressed pages.
buf_LRU_free_block(): Free compressed-only pages and their
descriptors with buf_buddy_free().

buf_LRU_get_free_only(): New function for returning a block from
buf_pool->free if one is available.  Split from buf_LRU_get_free_block().

buf_buddy_alloc_zip(): Rename from buf_buddy_alloc_low() and make static.
Remove parameter "split".  Always try to split.

buf_buddy_free_block(): Rename to buf_buddy_block_free().

buf_buddy_block_register(): New function for registering buf_block_t
objects reserved by the allocator.

buf_buddy_alloc_from(): New function for allocating an object from a
bigger object, and putting the unused parts on the free list.

buf_buddy_alloc_clean_zip(): New function for allocating memory by
replacing an unmodified compressed page.

buf_buddy_alloc_low(): New function for allocating memory, either from
the free lists of compressed pages, from the global free list, or from
unmodified pages in the buffer pool.
2006-12-11 14:27:43 +00:00
marko
bae7010964 branches/zip: buf_page_t: Rename free_or_flush_list to list
and document the possible list memberships.
2006-12-05 12:31:38 +00:00
marko
cce8ff1503 branches/zip: buf_LRU_free_block(): Note that
buf_LRU_block_remove_hashed_page() changes the state of the block.
This error was introduced in r1090.
2006-12-04 13:12:07 +00:00
marko
cbfc6cce6e branches/zip: Remove buf_block_t:free_list. Rename buf_page_t:flush_list
to free_or_flush_list.  The list node pointers can be shared, because a
block can never be belong to both lists at the same time.
2006-12-04 12:44:06 +00:00
marko
81d1179f04 branches/zip: page_zip_des_t: Enclose m_start in #ifdef UNIV_DEBUG.
Add m_nonempty for facilitating the test in page_zip_alloc().  This
reduces the combined size of the bit-fields to 32 bits.  Thus,
sizeof(page_zip_des_t) == 2 machine words on 32-bit and wider systems.
2006-11-30 14:09:29 +00:00