Technology Fundamentals 4: A Practical Overview

Crawl Budget: The interesting number is not the average, it is the 99th percentile. Crawl Budget: Adding a cache in front of a slow query is a fix; fixing the query is a cure. Crawl Budget: Every abstraction you add is a place where behaviour can differ from intent.

Edge Caching: You can often replace a coordination problem with an idempotency key. Edge Caching: Anything that grows without a bound will eventually hit one. Edge Caching: Documentation that is not tested tends to describe the previous version.

A boundary is a limit a person sets around their own body, time, privacy or emotional wellbeing. In a relationship, it might concern which kinds of physical contact feel welcome, whether a person wants to use a barrier method during sex, how personal information is shared, or when they need time alone. Boundaries can be broad, but clear examples are easier to understand and respect.

Data Pipelines: Serving static bytes is the cheapest thing you can do at the edge. Data Pipelines: A schema is an interface; changing it is a migration, not an edit. Data Pipelines: Track the denominator as carefully as the numerator.

Consider monitoring alerts specifically. The interesting number is not the average, it is the 99th percentile. Monitoring Alerts: Adding a cache in front of a slow query is a fix; fixing the query is a cure. Every abstraction you add is a place where behaviour can differ from intent. That applies to monitoring alerts as well.

Consider crawl budget specifically. Serving static bytes is the cheapest thing you can do at the edge. Crawl Budget: A schema is an interface; changing it is a migration, not an edit. Track the denominator as carefully as the numerator. That applies to crawl budget as well.

In practice, search indexing behaves differently: Periodic jobs should be safe to run twice, because they will be. You rarely need a new component to fix a boundary problem. The same reasoning holds for search indexing. For search indexing, the constraint matters more than the feature list. The signal you want is often already logged, just not aggregated.

In practice, load balancing behaves differently: If a metric has no owner, it will drift until it causes an incident. The cheapest optimisation is usually removing work nobody asked for. The same reasoning holds for load balancing. For load balancing, the constraint matters more than the feature list. Aggregating at write time trades flexibility for predictable read cost.

Search Indexing: The interesting number is not the average, it is the 99th percentile. Search Indexing: Adding a cache in front of a slow query is a fix; fixing the query is a cure. Search Indexing: Every abstraction you add is a place where behaviour can differ from intent.

Data Pipelines: If the rollback plan needs a meeting, it is not a rollback plan. Data Pipelines: Small pages that stay small are easier to keep fast than large ones made fast. Data Pipelines: Write the invariant down; otherwise it lives only in someone's memory.

Queue Design: Configurations should be reviewable in a diff, not only in a console. Queue Design: The best time to add an index is before the table gets large. Queue Design: Failures are usually correlated, so plan for the shared dependency.

The interesting number is not the average, it is the 99th percentile. That applies to release process as well. In practice, release process behaves differently: Adding a cache in front of a slow query is a fix; fixing the query is a cure. Every abstraction you add is a place where behaviour can differ from intent. The same reasoning holds for release process.

Queue Design: If the rollback plan needs a meeting, it is not a rollback plan. Queue Design: Small pages that stay small are easier to keep fast than large ones made fast. Queue Design: Write the invariant down; otherwise it lives only in someone's memory.

A yes is meaningful when a person can choose freely. Pressure can take many forms: repeated requests after a refusal, threats, guilt, intimidation, or using a position of authority to influence someone. A person who agrees because they fear consequences or feel unable to refuse may not be making a free choice.

Schema Markup: Configurations should be reviewable in a diff, not only in a console. Schema Markup: The best time to add an index is before the table gets large. Schema Markup: Failures are usually correlated, so plan for the shared dependency.

It can help to prepare a short sentence and a next step. For instance: “I want to take things slowly, so let’s check in before anything changes,” or “I don’t want photos taken or shared.” If you are unsure what you want, say so. “I’m still working that out, and I want to pause for now” communicates a limit without requiring you to settle every future question.

A design that cannot be rolled back is a design that cannot be changed safely. The same reasoning holds for observability. For observability, the constraint matters more than the feature list. Latency budgets are easier to defend when every hop has a stated ceiling. Teams working on observability usually discover this the hard way. Caching helps only until the invalidation rules become the bottleneck.

Data Pipelines: Configurations should be reviewable in a diff, not only in a console. Data Pipelines: The best time to add an index is before the table gets large. Data Pipelines: Failures are usually correlated, so plan for the shared dependency.

Cost Controls: You can often replace a coordination problem with an idempotency key. Cost Controls: Anything that grows without a bound will eventually hit one. Cost Controls: Documentation that is not tested tends to describe the previous version.

Backup Strategy: A design that cannot be rolled back is a design that cannot be changed safely. Backup Strategy: Latency budgets are easier to defend when every hop has a stated ceiling. Backup Strategy: Caching helps only until the invalidation rules become the bottleneck.

Load Balancing: A queue smooths spikes but also hides how far behind you are. Load Balancing: Retries without jitter turn a small outage into a large one. Load Balancing: Separating the reads from the writes buys room to change either side.

Schema Migration: A queue smooths spikes but also hides how far behind you are. Retries without jitter turn a small outage into a large one. That applies to schema migration as well. In practice, schema migration behaves differently: Separating the reads from the writes buys room to change either side.

Cost Controls: Periodic jobs should be safe to run twice, because they will be. Cost Controls: You rarely need a new component to fix a boundary problem. Cost Controls: The signal you want is often already logged, just not aggregated.

Edge Caching: If the rollback plan needs a meeting, it is not a rollback plan. Edge Caching: Small pages that stay small are easier to keep fast than large ones made fast. Edge Caching: Write the invariant down; otherwise it lives only in someone's memory.