Extract. Transform. Read.A newsletter from Pipeline Hi past, present or future data professional! One of the dirty secrets about my job is how easy it can be to fix broken pipelines. Often I’m retriggering a failed DAG task or, if using a code-less pipeline, literally hitting refresh. In fact, “refresh” is a great example for one of the more abstract data engineering concepts: State. And, specifically the maintenance of state under any condition. This is the definition of an important I-word, “idempotency.” While idempotency sounds like an SAT word, it’s as simple as saying “Every time this process runs the result (end state) will be the same.” An easy-to-grasp example of idempotency is the Google Cloud BigQuery API’s “WRITE_TRUNCATE” property. If you run a pipeline with “WRITE_TRUNCATE”, your data will always be overwritten during the load step. A more precise version of implementing idempotency is something I include in nearly all my pipelines, a DELETE step. This is slightly more precise than overwriting data because I am specifying deletion for a particular window. But this means that when I run a job that deletes and inserts only yesterday’s data, the output will be the same each time, leaving historic data intact and avoiding the very real possibility of data loss. This is a very practical approach to designing data pipelines because you may get spur-of-the-moment requests to reload data or otherwise re-trigger your runs. When executed properly, idempotency is as easy as hitting page refresh. Thanks for ingesting, -Zach Quinn |
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Extract. Transform. Read. A newsletter from Pipeline Hi past, present or future data professional! It’s hardly controversial to say debugging is everyone’s least favorite part of programming. One widely-used debugging method is the rubber duck method, popularized in Pragmatic Programming, which suggests you talk through your code, aloud, to an inanimate object. Being able to speak intelligently about what prompted a technical decision is one of the most underrated data engineering skills. One...
Extract. Transform. Read. A newsletter from Pipeline Hi past, present or future data professional! If you’re like me, in school you were always envious of your classmates that may not have applied themselves academically but were “good test takers.” Fortunately (for them at least), these folks would likely do well on what is quietly becoming the SAT of programming the GCA, or General Coding Assessment. Now, the General Coding Assessment isn’t any kind of board certifying test like the Bar...
Extract. Transform. Read. A newsletter from Pipeline Hi past, present or future data professional! While many tech-oriented companies have (in one way or another) reneged on remote working arrangements, my employer made an extreme gesture to demonstrate its commitment to the ongoing office-less lifestyle: It removed an entire floor of our two-floor New Jersey office space. Other companies, like Spotify, have unveiled slogans like “Our employees aren’t children. Spotify will continue working...