Revert of IndexedDB: Optimize range deletion operations (e.g. clearing a store)

Revert of IndexedDB: Optimize range deletion operations (e.g. clearing a store) (patchset #1 id:1 of https://codereview.chromium.org/2708223002/ )

Reason for revert:
Possibly related to indexdb test failures https://bugs.chromium.org/p/chromium/issues/detail?id=693048

Original issue's description:
> IndexedDB: Optimize range deletion operations (e.g. clearing a store)
> 
> Range deletion in leveldb involves walking over the range to identify
> keys to remove. The wrapper class used by IndexedDB to implement
> transactions was applying this same logic, which was inefficient due
> to (1) complexity in walking two iterators (one for the uncommitted
> transaction data and one for the backing store data) and (2) notifying
> iterators for every record.
> 
> This was optimized by clearing the range in the uncommitted data
> first, then simply walking the range in the backing store, and
> deferring notifying iterators until the end. This required removing
> the |delete_count| out param plumbed through various methods, but it
> was only used in tests.
> 
> On a test for clearing a store with 100k index entries, a 4x speedup
> was observed.
> 
> BUG=693799
> TEST=content_unittests --gtest_filter='LevelDBTransactionTest.*'
> 
> Review-Url: https://codereview.chromium.org/2708223002
> Cr-Commit-Position: refs/heads/master@{#452324}
> Committed: https://chromium.googlesource.com/chromium/src/+/339d49e89f42347c7b85ac31cb0e9ebd8163025d

TBR=cmumford@chromium.org,dmurph@chromium.org,jsbell@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=693799
Review-Url: https://codereview.chromium.org/2710203002
Cr-Commit-Position: refs/heads/master@{#452442}
Committed: https://chromium.googlesource.com/chromium/src/+/a9e4f703d78e0cf23ecba81eced44ec3a9712bec

[keishi, 2017-02-23 09:38:32]

The CQ bit was checked by keishi@chromium.org

[keishi, 2017-02-23 09:38:33]

Created Revert of IndexedDB: Optimize range deletion operations (e.g. clearing a
store)

[commit-bot: I haz the power, 2017-02-23 09:38:50]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-02-23 09:39:32]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1487842712678010, "parent_rev":
"8514e79471d9dfa4a9376317b86f45b57e11eea6", "commit_rev":
"a9e4f703d78e0cf23ecba81eced44ec3a9712bec"}

[commit-bot: I haz the power, 2017-02-23 09:40:15]

Description was changed from

==========
Revert of IndexedDB: Optimize range deletion operations (e.g. clearing a store)
(patchset #1 id:1 of https://codereview.chromium.org/2708223002/ )

Reason for revert:
Possibly related to indexdb test failures
https://bugs.chromium.org/p/chromium/issues/detail?id=693048

Original issue's description:
> IndexedDB: Optimize range deletion operations (e.g. clearing a store)
> 
> Range deletion in leveldb involves walking over the range to identify
> keys to remove. The wrapper class used by IndexedDB to implement
> transactions was applying this same logic, which was inefficient due
> to (1) complexity in walking two iterators (one for the uncommitted
> transaction data and one for the backing store data) and (2) notifying
> iterators for every record.
> 
> This was optimized by clearing the range in the uncommitted data
> first, then simply walking the range in the backing store, and
> deferring notifying iterators until the end. This required removing
> the |delete_count| out param plumbed through various methods, but it
> was only used in tests.
> 
> On a test for clearing a store with 100k index entries, a 4x speedup
> was observed.
> 
> BUG=693799
> TEST=content_unittests --gtest_filter='LevelDBTransactionTest.*'
> 
> Review-Url: https://codereview.chromium.org/2708223002
> Cr-Commit-Position: refs/heads/master@{#452324}
> Committed:
https://chromium.googlesource.com/chromium/src/+/339d49e89f42347c7b85ac31cb0e...

TBR=cmumford@chromium.org,dmurph@chromium.org,jsbell@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=693799
==========

to

==========
Revert of IndexedDB: Optimize range deletion operations (e.g. clearing a store)
(patchset #1 id:1 of https://codereview.chromium.org/2708223002/ )

Reason for revert:
Possibly related to indexdb test failures
https://bugs.chromium.org/p/chromium/issues/detail?id=693048

Original issue's description:
> IndexedDB: Optimize range deletion operations (e.g. clearing a store)
> 
> Range deletion in leveldb involves walking over the range to identify
> keys to remove. The wrapper class used by IndexedDB to implement
> transactions was applying this same logic, which was inefficient due
> to (1) complexity in walking two iterators (one for the uncommitted
> transaction data and one for the backing store data) and (2) notifying
> iterators for every record.
> 
> This was optimized by clearing the range in the uncommitted data
> first, then simply walking the range in the backing store, and
> deferring notifying iterators until the end. This required removing
> the |delete_count| out param plumbed through various methods, but it
> was only used in tests.
> 
> On a test for clearing a store with 100k index entries, a 4x speedup
> was observed.
> 
> BUG=693799
> TEST=content_unittests --gtest_filter='LevelDBTransactionTest.*'
> 
> Review-Url: https://codereview.chromium.org/2708223002
> Cr-Commit-Position: refs/heads/master@{#452324}
> Committed:
https://chromium.googlesource.com/chromium/src/+/339d49e89f42347c7b85ac31cb0e...

TBR=cmumford@chromium.org,dmurph@chromium.org,jsbell@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=693799

Review-Url: https://codereview.chromium.org/2710203002
Cr-Commit-Position: refs/heads/master@{#452442}
Committed:
https://chromium.googlesource.com/chromium/src/+/a9e4f703d78e0cf23ecba81eced4...
==========

[commit-bot: I haz the power, 2017-02-23 09:40:17]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/a9e4f703d78e0cf23ecba81eced4...

[keishi, 2017-02-23 09:42:58]

Failed bots
https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Linu...
https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Win7...
https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Linu...
https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Win7...
...

[keishi, 2017-02-23 09:44:04]

crbug.com/695371

[jsbell, 2017-02-23 17:33:30]

On 2017/02/23 09:44:04, keishi wrote:
> crbug.com/695371

Thanks for the revert!