[sql] Use IGNORE conflict resolution in recovery.

[sql] Use IGNORE conflict resolution in recovery.

One way databases get corrupted is when pages cross transaction
boundaries.  Both pages can be valid, but they could contain overlapping
data, resulting in UNIQUE constraint violations.  AutoRecoverTable()
handled this by using INSERT OR REPLACE to cause later items to
overwrite earlier items.

Change to INSERT OR IGNORE.  This drops later items for UNIQUE
violations, but also handles other constraint violations.

BUG=none

Committed: https://crrev.com/806f499866733d4561aac73f9129d5f5ab727ddd
Cr-Commit-Position: refs/heads/master@{#373617}

[Scott Hess - ex-Googler, 2016-02-03 22:35:00]

shess@chromium.org changed reviewers:
+ rch@chromium.org

[Scott Hess - ex-Googler, 2016-02-03 22:37:20]

https://codereview.chromium.org/1665913003/diff/1/sql/recovery_unittest.cc
File sql/recovery_unittest.cc (right):

https://codereview.chromium.org/1665913003/diff/1/sql/recovery_unittest.cc#ne...
sql/recovery_unittest.cc:377: EXPECT_TRUE(results=="100" || results=="0") <<
"Actual results: " << results;
REPLACE retained the last version encountered, IGNORE retains the first eversion
encountered.  But "first" and "last" are anyhow implementation-dependent, so
this change just asserts that the value retained is one of the values inserted.

[Ryan Hamilton, 2016-02-04 01:38:17]

lgtm

https://codereview.chromium.org/1665913003/diff/1/sql/recovery.cc
File sql/recovery.cc (left):

https://codereview.chromium.org/1665913003/diff/1/sql/recovery.cc#oldcode431
sql/recovery.cc:431: // http://www.sqlite.org/lang_conflict.html
Looks like you planned ahead! Nice comment.

[Scott Hess - ex-Googler, 2016-02-04 21:01:57]

The CQ bit was checked by shess@chromium.org

[commit-bot: I haz the power, 2016-02-04 21:04:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1665913003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1665913003/1

[commit-bot: I haz the power, 2016-02-04 21:12:15]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-02-04 21:13:02]

Description was changed from

==========
[sql] Use IGNORE conflict resolution in recovery.

One way databases get corrupted is when pages cross transaction
boundaries.  Both pages can be valid, but they could contain overlapping
data, resulting in UNIQUE constraint violations.  AutoRecoverTable()
handled this by using INSERT OR REPLACE to cause later items to
overwrite earlier items.

Change to INSERT OR IGNORE.  This drops later items for UNIQUE
violations, but also handles other constraint violations.

BUG=none
==========

to

==========
[sql] Use IGNORE conflict resolution in recovery.

One way databases get corrupted is when pages cross transaction
boundaries.  Both pages can be valid, but they could contain overlapping
data, resulting in UNIQUE constraint violations.  AutoRecoverTable()
handled this by using INSERT OR REPLACE to cause later items to
overwrite earlier items.

Change to INSERT OR IGNORE.  This drops later items for UNIQUE
violations, but also handles other constraint violations.

BUG=none

Committed: https://crrev.com/806f499866733d4561aac73f9129d5f5ab727ddd
Cr-Commit-Position: refs/heads/master@{#373617}
==========

[commit-bot: I haz the power, 2016-02-04 21:13:03]

Patchset 1 (id:??) landed as
https://crrev.com/806f499866733d4561aac73f9129d5f5ab727ddd
Cr-Commit-Position: refs/heads/master@{#373617}