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Apply InnoDB snapshot innodb-5.1-2858, part 7.

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A follow-up fix for Bug 38839, which exposed a pre-existing bug in the
autoinc handling.

Detailed revision comments:

r2722 | sunny | 2008-10-04 02:48:04 +0300 (Sat, 04 Oct 2008) | 18 lines
branches/5.1: This bug has always existed but was masked by other errors. The
fix for bug# 38839 triggered this bug. When the offset and increment are > 1
we need to calculate the next value taking into consideration the two
variables. Previously we simply assumed they were 1 particularly offset was
never used. MySQL does its own calculation and that's probably why it seemed
to work in the past. We would return what we thought was the correct next
value and then MySQL would recalculate the actual value from that and return
it to the caller (e.g., handler::write_row()). Several new tests have been
added that try and catch some edge cases. The tests exposed a wrap around
error in MySQL next value calculation which was filed as bug 39828. The tests
will need to be updated once MySQL fix that bug.

One good side effect of this fix is that dict_table_t size has been
reduced by 8 bytes because we have moved the autoinc_increment field to
the row_prebuilt_t structure. See review-board for a detailed discussion.

rb://3
This commit is contained in:
Timothy Smith
2008-12-14 13:42:37 -07:00
parent e366921268
commit 22f6a8424c
7 changed files with 713 additions and 40 deletions
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11
storage/innobase/include/row0mysql.h
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@ -683,7 +683,16 @@ struct row_prebuilt_struct {
to this heap */
mem_heap_t* old_vers_heap; /* memory heap where a previous
version is built in consistent read */
ulonglong last_value; /* last value of AUTO-INC interval */
/*----------------------*/
ulonglong autoinc_last_value;/* last value of AUTO-INC interval */
ulonglong autoinc_increment;/* The increment step of the auto
increment column. Value must be
greater than or equal to 1. Required to
calculate the next value */
ulonglong autoinc_offset; /* The offset passed to
get_auto_increment() by MySQL. Required
to calculate the next value */
/*----------------------*/
ulint magic_n2; /* this should be the same as
magic_n */
};