351793 – Enhance LockMgr with write options

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Bug 351793 - Enhance LockMgr with write options

Summary: Enhance LockMgr with write options

Status:	CLOSED FIXED

Alias:	None

Product:	EMF
Classification:	Modeling
Component:	cdo.core (show other bugs)
Version:	4.1
Hardware:	All All

Importance:	P3 enhancement (vote)
Target Milestone:	---
Assignee:	Caspar D.
QA Contact:	Eike Stepper

URL:
Whiteboard:	Power to the People
Keywords:

Depends on:
Blocks:	352330
	Show dependency tree

Reported:	2011-07-12 02:24 EDT by Caspar D.
Modified:	2012-09-21 07:16 EDT (History)
CC List:	1 user (show)

See Also:

Flags:	stepper: review+ stepper: review+

Attachments
Patch v1 (14.01 KB, patch) 2011-07-12 02:37 EDT, Caspar D.	no flags	Details \| Diff
Patch v2 (14.28 KB, patch) 2011-07-12 04:19 EDT, Caspar D.	no flags	Details \| Diff
Patch v3 (22.20 KB, patch) 2011-07-12 05:46 EDT, Caspar D.	no flags	Details \| Diff
Patch v4 (26.31 KB, patch) 2011-07-13 01:35 EDT, Caspar D.	no flags	Details \| Diff
Patch v5 (26.68 KB, patch) 2011-07-13 01:58 EDT, Caspar D.	no flags	Details \| Diff
Patch v6 (50.25 KB, patch) 2011-07-13 06:01 EDT, Caspar D.	no flags	Details \| Diff
Patch v7 (50.16 KB, patch) 2011-07-13 07:21 EDT, Caspar D.	no flags	Details \| Diff
Patch v8 (46.24 KB, patch) 2011-07-18 04:51 EDT, Caspar D.	no flags	Details \| Diff
Patch v9 (31.89 KB, patch) 2011-07-22 02:09 EDT, Eike Stepper	no flags	Details \| Diff
Patch v10 - ready to be committed (36.56 KB, patch) 2011-07-22 02:43 EDT, Eike Stepper	no flags	Details \| Diff
Patch (JavaDocs) (2.45 KB, patch) 2011-07-26 03:04 EDT, Caspar D.	no flags	Details \| Diff
Patch v2 (JavaDocs + logic) (6.39 KB, patch) 2011-07-26 04:25 EDT, Caspar D.	no flags	Details \| Diff
Patch v3 (JavaDocs + logic) (6.36 KB, patch) 2011-07-26 05:40 EDT, Caspar D.	no flags	Details \| Diff
Show Obsolete (11) View All Add an attachment (proposed patch, testcase, etc.)

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Description Caspar D.

2011-07-12 02:24:51 EDT

A write option (or write reservation) is a lock that prevents other
views from obtaining a write lock, but does not prevent others from
obtaining read locks. How is it different from a read lock? A write
option can only be held by *one* view. Why do we need this? So that
apps can prevent writes without preventing read locking.

Patch coming up.

Comment 1 Caspar D.

2011-07-12 02:37:58 EDT

Created attachment 199467 [details]
Patch v1

Incomplete, only contains a crude version of the new lockMgr.
Changes to client-side API not yet done.

Comment 2 Caspar D.

2011-07-12 04:19:09 EDT

Created attachment 199472 [details]
Patch v2

All existings tests passing now, except those verifying persistent
locks. New tests (verifying WRITE_OPTION behavior) yet to be done.

Comment 3 Caspar D.

2011-07-12 05:46:41 EDT

Created attachment 199477 [details]
Patch v3

All existing tests passing now.

TBD:
- Client-side API
- New tests for WRITE_OPTION locks

Comment 4 Caspar D.

2011-07-13 01:35:51 EDT

Created attachment 199539 [details]
Patch v4

Refactored changes based on new insight that there are no API constraints
on changes to an internal class.

Comment 5 Caspar D.

2011-07-13 01:58:55 EDT

Created attachment 199541 [details]
Patch v5

Refactored again; base class now genericized, and moved to net4j.util

Comment 6 Caspar D.

2011-07-13 06:01:40 EDT

Created attachment 199558 [details]
Patch v6

Functionality complete, I believe.

TBD: Performance optimizations, especially view-to-locks lookup

Comment 7 Caspar D.

2011-07-13 07:21:04 EDT

Created attachment 199567 [details]
Patch v7

Forgot to persist those write options! Better now :-)

Comment 8 Caspar D.

2011-07-18 04:51:48 EDT

Created attachment 199814 [details]
Patch v8

Performance optimizations

Comment 9 Eike Stepper

2011-07-22 02:09:33 EDT

Created attachment 200142 [details]
Patch v9

I broke the tests ;-(

Comment 10 Eike Stepper

2011-07-22 02:43:46 EDT

Created attachment 200146 [details]
Patch v10 - ready to be committed

Good work!

Comment 11 Eike Stepper

2011-07-22 02:44:41 EDT

I can approve the patch when Javadoc has been added to CDOObject.cdoWriteOption() and RWOLockManager ;-)

Comment 12 Eike Stepper

2011-07-22 02:45:15 EDT

Actually I did approve it and rely on your promise to add JavaDocs ;-)

Comment 13 Caspar D.

2011-07-22 02:50:37 EDT

Committed revision 8806.

Not resolving yet, cause JavaDocs yet to be done.

Comment 14 Caspar D.

2011-07-26 03:04:34 EDT

Created attachment 200333 [details]
Patch (JavaDocs)

Added JavaDocs.

Comment 15 Eike Stepper

2011-07-26 03:30:12 EDT

> a read lock prevents write locks by others, but allows read locks by others, and is therefore <b>non-exclusive</b>

How are write option requests impacted?

> a write lock prevents read locks by others and write locks by others, and is therefore <b>exclusive</b>

How are write option requests impacted?

> a write option prevents write locks by others and write options by others, but allows read locks by others, and is therefore <b>exclusive</b>

Comment 16 Caspar D.

2011-07-26 03:50:13 EDT

(In reply to comment #15)
> > a read lock prevents write locks by others, but allows read locks by others, and is therefore <b>non-exclusive</b>
> 
> How are write option requests impacted?

They're not.

> > a write lock prevents read locks by others and write locks by others, and is therefore <b>exclusive</b>
> 
> How are write option requests impacted?
> 

They're not.. but in this case I your question makes me realize that
this is a mistake. A write lock must prevent write options by others.

Will amend both the docs and the logic.

Comment 17 Eike Stepper

2011-07-26 03:51:15 EDT

Excellent ;-)

Comment 18 Caspar D.

2011-07-26 04:25:07 EDT

Created attachment 200342 [details]
Patch v2 (JavaDocs + logic)

Comment 19 Caspar D.

2011-07-26 05:40:22 EDT

Created attachment 200345 [details]
Patch v3 (JavaDocs + logic)

Comment 20 Caspar D.

2011-07-26 06:20:46 EDT

Committed revision 8820.

Comment 21 Caspar D.

2011-07-26 06:24:10 EDT

Resolving as FIXED.

Comment 22 Eike Stepper

2012-09-21 07:16:32 EDT

Closing.