SQL SQLAlchemy issue keep happened

I have a bot that almost finished but only one bug haven't found solution yet, I need someone to fix this issue.

This is a bot that will keep visit specific website and rotate IP each time.

Bot was written in Python 3 using latest beta ChromeDriver 76.0.3809.68, stable versions were previously used but the issue was keep reproducing.

App is concurrently run Chrome Driver to emulate traffic visits on projects on [login to view URL] website.

Currently there are 5 threads that are using StormProxies service for IP hiding.

One of the solutions to avoid running out of memory in case of broken proxies and hanging Chrome session was to run ‘killall chrome’ every 2 hours. To implement this task cron task was created

1. crontab -e

2. 0 */2 * * * killall chrome

After migration from SQLite to Postgres after some period (not permanent) of bot execution it hangs with following SQLAlchemy errors:

1. 2019-06-18 00:37:05 : rank_project : This session is in 'prepared' state; no further SQL can be emitted within this transaction.

2. 2019-07-16 02:28:32 : rank_project : Instance '<AccountRankTask at 0x7f4828acca90>' is not persistent within this Session

To solve this errors different variations of DB engine and Session options was applied but none of them actually resolved an issue.

Migration was done since SQLite was not able handle multiple transactions due to it lightweight architecture that lock DB file for writing (current errors ‘OperationalError: database is locked’ began to appear)

Python MySQL Selenium Webdriver

Project ID: #20580447

About the project