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For me choosing a database involves carefully considering the value of data that will be housed within. To what degree do I care about the data? How long would

by mrmondo 13y ago

For me choosing a database involves carefully considering the value of data that will be housed within. To what degree do I care about the data? How long would it take to recreate? What's the cost to my business if data is lost. Time and time again, I end up choosing PostgreSQL for ANY data that I care about (i.e. anything that is not simply 'in-flight data'.

falcolas 13y ago
From the point of view of a "devops" developer - who has done hard time in QA and DBA as well - this requirement changes drastically when performance and scaling enter the equation. The scale slides quickly from "lose no data, ever" to "we can lose a few seconds of transactions if it speeds up the web page" to "we can lose a lot of data and still be OK, as long as we're still online". Seconds, or even minutes worth of lost data do cost the company, but not nearly as much as poor performance. And unfortunately, developers tend to over-value data in the equation, leading to decisions which cause a company problems when it comes time to grow. Ultimately, the best tools for ensuring business continuity (with few exceptions) is redundancy coupled with a set of proper backups.
- olavgg 13y ago
  Wouldn't message queues help you with this? They can be easily scaled horizontally to handle any write load and correctly insert data to the database safe over time. You can also shard your database to distribute write load.
  - falcolas 13y ago
    All of those absolutely help, at the cost of added complexity, additional points of failure, and hardware/VPS costs. And you still risk losing data, or at least data integrity. Not to mention there are still hard limits on how quickly you can insert data into a database with 100% durability (which is, of course, impossible, but another topic entirely), and there are scales where even these mitigation tactics can't help you anymore (in particular, online casino games have this problem since they are persisting the state of multiple players very frequently).
- mrmondo 13y ago
  Out of interest, What hardware have you tried running your Postgres clusters on?

by mrmondo 13y ago

falcolas 13y ago

From the point of view of a "devops" developer - who has done hard time in QA and DBA as well - this requirement changes drastically when performance and scaling enter the equation. The scale slides quickly from "lose no data, ever" to "we can lose a few seconds of transactions if it speeds up the web page" to "we can lose a lot of data and still be OK, as long as we're still online". Seconds, or even minutes worth of lost data do cost the company, but not nearly as much as poor performance. And unfortunately, developers tend to over-value data in the equation, leading to decisions which cause a company problems when it comes time to grow. Ultimately, the best tools for ensuring business continuity (with few exceptions) is redundancy coupled with a set of proper backups.

olavgg 13y ago
Wouldn't message queues help you with this? They can be easily scaled horizontally to handle any write load and correctly insert data to the database safe over time. You can also shard your database to distribute write load.
- falcolas 13y ago
  All of those absolutely help, at the cost of added complexity, additional points of failure, and hardware/VPS costs. And you still risk losing data, or at least data integrity. Not to mention there are still hard limits on how quickly you can insert data into a database with 100% durability (which is, of course, impossible, but another topic entirely), and there are scales where even these mitigation tactics can't help you anymore (in particular, online casino games have this problem since they are persisting the state of multiple players very frequently).
mrmondo 13y ago
Out of interest, What hardware have you tried running your Postgres clusters on?