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MDEV-33542 Inplace algorithm occupies more disk space compared to copy algorithm

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Problem:
=======
- In case of large file size, InnoDB eagerly adds the new extent
even though there are many existing unused pages of the segment.
Reason is that in case of larger file size, threshold
(1/8 of reserved pages) for adding new extent has been
reached frequently.

Solution:
=========
- Try to utilise the unused pages in the segment before adding
the new extent in the file segment.

need_for_new_extent(): In case of larger file size, try to use
the 4 * FSP_EXTENT_SIZE as threshold to allocate the new extent.

fseg_alloc_free_page_low(): Rewrote the function to allocate
the page in the following order.
1) Try to get the page from existing segment extent.
2) Check whether the segment needs new extent
(need_for_new_extent()) and allocate the new extent,
find the page.
3) Take individual page from the unused page from
segment or tablespace.
4) Allocate a new extent and take first page from it.

Removed FSEG_FILLFACTOR, FSEG_FRAG_LIMIT variable.
This commit is contained in:
Thirunarayanan Balathandayuthapani
2024-03-19 17:14:11 +05:30
parent 5b4e69c059
commit c3a6248bba
4 changed files with 77 additions and 105 deletions
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6
mysql-test/suite/innodb/r/innodb_bug30113362.result
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@@ -37,7 +37,7 @@ test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
CLUST_INDEX_SIZE
1856
1792
connection con2;
DELETE FROM t1 WHERE a00 = 'cnm';
COMMIT;
@@ -80,7 +80,7 @@ test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
CLUST_INDEX_SIZE
1856
1792
DELETE FROM t1 WHERE a00 = 'dpn';
COMMIT;
INSERT INTO t1 SET a00 = 'dpn';
@@ -117,6 +117,6 @@ test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
SELECT CLUST_INDEX_SIZE FROM information_schema.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
CLUST_INDEX_SIZE
1856
1792
SET DEBUG_SYNC = 'RESET';
DROP TABLE t1;