Magento 2 Search Result Sort Order Changes on Refresh

So, as this gets a bit long in the comments and you'll anyway have to debug it on your own i'll write down the main problem of this error message and how you could continue to debug it.

/solr/update?wt=jsonstore_id:13600 looks for an input document to index. So calling this URL directly will always end up in this "missing content stream" error.

As already mentioned in the comments every request to Solr in Magento runs through Apache_Solr_Service::__sendRawPost in the lib directory. This is not Magento specific code, it's an implementation of the official PHP Solr Client published by Apache. You can also find some small docs over here: https://code.google.com/p/solr-php-client/

You mentioned that this position is called 3 times, so you should check when exactly the error code 400 is returned. I would recommend to use XDebug and check the response which is initialized also in that same method.

When the update action is called Magento should submit a list of documents (products on Magento site) which Solr has to index. You can also check the current index status with a tool called luke on your solr server: /solr/admin/luke/ This gives you information about the amount of indexed documents and terms and the latest update time, which helps a lot to debug this stuff and see if indexing was successful.

Besides that, what version of EE do you use? There are anyway some open bugs in 1.12 (I don't know if they fixed it in 1.13) and we provided some patches, which might help you to run in further problems: https://github.com/sitewards/SolrPatches

Sorry that I can't give you a direct solution, but with this information it should be possible to debug that stuff on your system and find the error pretty fast.

In super-short: see Search Type: Like, Full Text or Combined?

In short, Magento's default search is not great.

That said, all I can really recommend is tweaking/configuring to improve the search behavior. Some things to consider (if you have not already):

• Tweak product attributes to limit which attributes are being searched - if all you care about is the product name and description, considering setting the "searchable" field to false for other fields. This may not meet your requirements, but it might be worth experimenting with
• Use the "search terms" feature of Magento (Catalog -> Search Terms). If you want "6D" to always bring customers to the 6D body (or kit, etc) product page, you can do that with the search terms feature. This is perhaps not a solution the bad search, but at least can help triage some of the more important search terms and fix the most common problem terms.
• Consider tweaking the Search Type (System -> Configuration -> Catalog (left) -> Catalog Search) and again, read more here

In my experience with search in Magento, no search is going to be absolutely perfect out of the box. I think that Search Terms is actually a great tool for helping you get a handle on major problem areas, and some tweaking of Magento search options/attributes can make the default search at least workable. Magento's SOLR implementation is notoriously bad (and in my experience, that's relatively accurate). There are great third party modules out there (my company is actually developing one), but as you said they do require a bit more setup, and again, even still you're going to need to tweak things.