don't save index events for indexers in manual mode

[bob2021]

This is part of a group of PRs containing the changes discussed in issue #152

If an indexer is in manual mode, there is no need to save an index event as it will never be processed - manual mode indexes can only be updated using a full reindex.

Index event data can grow very large (megabytes) for mass_action events. It is not cleaned properly after processing and new data is often appended without deduplication.

This PR prevents index events from registering with an indexer if it is in manual mode. It also ensures that index data is cleaned during a partial 'full' reindex.

[Flyingmana]

some of the async index modules are actually making use of this, one example is https://github.com/magento-hackathon/AsyncIndex

and as it is something which is really used inside the EE version, Iam sure there are more modules out there, who use this to patch functionality into the CE

[bob2021]

I am no longer involved with Magento development and I will not be contributing any further changes to this PR so I am closing it.

[addison74]

I understand the situation but a simple statement that you are no longer involved in the project was enough without closing the PR, leaving it to the appreciation of others who are still active if your work so far can be useful OpenMage.

[fballiano]

some of the async index modules are actually making use of this, one example is https://github.com/magento-hackathon/AsyncIndex

and as it is something which is really used inside the EE version, Iam sure there are more modules out there, who use this to patch functionality into the CE

@Flyingmana would it be better, in your opinion, to live the code as it is for compatibility with other modules?

I kinda think that this PR is a good one to be implemented in our code.

[tobihille]

As a compromise between this PR and @Flyingmana's statement I would suggest that a cron is created that deletes the old events if they are not consumed by e.g. AsyncIndex.
This way the DB will not overflow and BC is guaranteed (at least for the configured time).
Sadly I don't know how to contribute to a PR that is not mine, would it be beneficial if I create my own PR and reference this one?

[addison74]

@tobihille - The author chose not to contribute to OM anymore and I thank him for letting us know. I left the PR open because it needs modifications. If you consider you can create a better one please feel free to open your own PR and we will close this one.

[fballiano]

I'm taking responsibility and closing this, it is a very good idea IMHO but so is the asyncIndex and #2474 is the right middleway