Google indexing 50% of my pages

[Coldfaun]

Hello everyone.

I have a blog that has about 1000 articles.
Only about 500 are indexed in google, as I see in Webmaster Tools.

I am not sure what is the reason the other 500 are not indexed.
I've noticed that the article quality is not a cause.

A week ago I wrote about 10 articles, one that has about 1000 words and is a great article in my opinion, is not indexed even though the others from those 10 are indexed.

Is there any reason for this indexing issue?
Does google never index all the blog posts regardless of their content quality?

Note: I have a sitemap added with all the blog posts (from the yoast plugin)

[Coldfaun]

The blog is from 2013 and has a bit of traffic, so it's not a cheap spammy website.

[NickMNS]

Google doesn't always index the entire website. The larger the site the less likely it is to be fully indexed. Links and traffic are what determine what gets indexed.

[Coldfaun]

Thank you for your reply. It's sad to see a good article that has a review for a bicycle that seem unique, nobody has made one yet except me, and it's not indexed because of this algorithm.

I just checked and the page is indexed in bing and duckduckgo which seem to route some traffic towards my website, but not on Google.

[jediviper]

Are there any internal links pointing to this unique bicycle article?
Maybe from the header/footer or from other pages or from external media, like social media pages?

I have never had issues indexing any new pages, but sometimes it can take 3-7 days for this.

[lucy24]

Obligatory caution: Don’t take G’s word for it; check for yourself. Try exact-text searches for random phrases from the pages they say aren’t indexed.

They may, in fact, be telling the truth. I checked my own site and found several pages listed as “crawled but not indexed”. This turned out not only to be correct, but there are other related pages that are also not indexed though not listed on GSC as such. In my case, I can generally see what decisions G made. And not being indexed does protect me from the ongoing annoyance of “do my homework for me” searches.

The More Info page says

It may or may not be indexed in the future; no need to resubmit this URL for crawling.

which must be filed under Unhelpful Information.