1. RelStorage
Plone
Relational
Database
Storage
Backend

2. Overview
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Drop-in replacement for FileStorage or ZEO
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For PostgreSQL, MySQL, Oracle, SQLite
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settled: around for ~13 years
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Active development driven by Jason Madden:
Version 3 released 2019
Latest release 3.4.0 in October 2020

3. PostgreSQL the Cloud DB
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Kind of „Industry Standard“.
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Well supported by all big cloud providers:
AWS, Google, Azure, IBM, Heroku, ...
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Easy to install in private clouds (or local):
Docker, Kubernetes, ...
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Very well maintained and thriving development
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Scaling solutions available

4. Advantages
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Fast, parallel commits, better
concurrency, shorter locks
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Optimized per process caching
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Blobs in database
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Optional history free

5. Usage: Setup
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„plone.recipe.zope2instance“ buildout support
minimal example
[instance]
eggs +=
RelStorage
psycopg2
sharedblobs = false
rel-storage =
type postgresql
dsn dbname='plone' host='localhost' user='plone' password='secret'
keep-history false

6. Usage: Caches
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additional client side caches
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shared between all threads of process
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Optional compressed
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Parameters to limit size, object count and
max-size of objects in this cache

7. Converting from FS or ZEO
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„zodbconvert“ converts from any storage
to another, like from ZEO to RelStorage
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Needs configuration file providing
connections to both storages
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Also converts blobs if needed

8. Packing
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ZODB keeps old transactions, so packing
is needed
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In history free mode only deleted objects
need to be cleaned up (DB bloats less)
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RelStorage provides a fast „zodbpack“

9. Versions and Blobs
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RelStorage 3.x is Python 3 only and runs
with Plone 5.2+ - Blobs should be stored
in RelStorage
●
RelStorage 2.x is for Plone 5.0-5.1.x,
blobs should not be stored in DB, except
for Oracle backends.

10. Personal Note
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I use RelStorage today for all my live
deployments
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Use it since v.1.6 with Plone 4.3
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Never had problems
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Blazing fast
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DevOps/Sysadmins love it