A connection pool is a queue you forgot to size
The claim The default database connection pool in most application frameworks is set to a number someone picked because it looked reasonable, and it is almost always wrong in the s...
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Engineering
Engineering notes, infrastructure deep dives and practical guides from the Exotecho team.
Read the query plan before you add another index
The claim Adding an index because a query is slow, without first reading the plan the database uses to run it, is guessing — and it frequently makes things worse, because every ind...
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A cron job with no alert is a job you are not running
The claim A scheduled job that runs silently and is only noticed when it fails is not a reliable job — it is a job that has already failed silently at least once and nobody knew. C...
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Measure the p99, because the average hides your worst day
The claim An average response time is close to useless as a health metric, because it is dominated by the many fast requests and says nothing about the few slow ones — and the slow...
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Your slowest ten queries are a twenty-minute report
The claim Before you scale up the database instance, add a read replica, or rewrite an endpoint, run one query. In almost every under-performing application we are asked to look at...
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Store money as integer cents, never as a float
The claim A floating-point number cannot represent ten cents exactly, so any system that stores money in a float column will, given enough transactions, produce totals that are off...
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Put a UUID on the invoice before you need it
The claim Give every business record a stable, public-safe identifier at the moment it is created, separate from its database primary key. The auto-incrementing integer is fine ins...
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Offset pagination lies to you after page fifty
The claim LIMIT 20 OFFSET 5000 has two defects, and the well-known one is the lesser. Yes, it gets slower linearly, because the database must produce and discard five thousand rows...
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Every feature flag needs a deletion date
The claim A feature flag is a deployment tool with a lifespan measured in weeks. A flag that survives past its launch becomes permanent configuration nobody understands, and a code...
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