Message 322281 - Python tracker

Message322281

Author	serhiy.storchaka
Recipients	alexandre.vassalotti, lukasz.langa, serhiy.storchaka
Date	2018-07-24.09:16:42
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1532423802.47.0.56676864532.issue34204@psf.upfronthosting.co.za>
In-reply-to

Content
The default pickle protocol is 4 now. But shelve still uses the pickle protocol 3. Shouldn't it be bumped? Shouldn't shelve use pickle.DEFAULT_PROTOCOL by default? Disadvantages: 1. This will make shelve files incompatible with Python 3.3 by default. 2. Protocol 4 adds 9 bytes of overhead in comparison with protocol 3. This can be too large for the shelve containing a lot of small objects. Maybe strip redundant frame header for small pickles?

Content

The default pickle protocol is 4 now. But shelve still uses the pickle protocol 3. Shouldn't it be bumped? Shouldn't shelve use pickle.DEFAULT_PROTOCOL by default?

Disadvantages:

1. This will make shelve files incompatible with Python 3.3 by default.

2. Protocol 4 adds 9 bytes of overhead in comparison with protocol 3. This can be too large for the shelve containing a lot of small objects. Maybe strip redundant frame header for small pickles?

History
Date	User	Action	Args
2018-07-24 09:16:42	serhiy.storchaka	set	recipients: + serhiy.storchaka, alexandre.vassalotti, lukasz.langa
2018-07-24 09:16:42	serhiy.storchaka	set	messageid: <1532423802.47.0.56676864532.issue34204@psf.upfronthosting.co.za>
2018-07-24 09:16:42	serhiy.storchaka	link	issue34204 messages
2018-07-24 09:16:42	serhiy.storchaka	create