For last few months I've been tinkering with writing a desktop IMAP email client in JavaScript. I am working on creating a sync algorithm and using my GMail account as the test account.
As of last month, my current sync algorithm could sync the structure of my account (~190 folders and ~165k messages) in under 8 minutes from scratch. Over the last few weeks, I noticed my sync time drop down to over 30 minutes and I am getting timeouts fetching messages. Since I was traveling, I attributed that to potentially bad connectivity; however, I am seeing the same issues now that I am back home.
I am effectively querying the IMAP server for:
[ 'flags', 'BODY.PEEK[HEADER.FIELDS (FROM TO SUBJECT DATE MESSAGE-ID REFERENCES IN-REPLY-TO)]' ]
When syncing from scratch, I am requesting the above information from the IMAP server in chunks of 5000 messages at a time. This had been working fine for a few months and only recently started acting up in the last three weeks.
For each fetch of messages, I would set a timeout of 30secs and I never saw it expire, but now even if I push the timeout to 60secs I'm still getting failures.
I'm about ready to throw up my hands. Does anyone know if Gmail IMAP access has slowed recently or is being throttled?
I have tested against multiple email accounts and from multiple computers (both before and after). Before everything was quick everywhere. Now everything is slow everywhere.