Original, source-backed articles about running small systems, static sites, HTTP, DNS, TLS, and operations.
Posts are original articles written for this site. Each one is script-free, source-backed, and tied to the same operational reality the rest of the site records: how a small, static, publicly served system is built, secured, and kept honest.
Cache-Control is a contract between cache and origin
A cache policy needs a behavioral test, not just a header-presence check. Two responses can both contain max-age yet behave differently because one also requires validation or prohibits storage. The request matters too: a browser can bypass an otherwise reusable copy without changing the origin’s response policy or deleting an older cached entry.
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A Common Table Expression names a query you can reuse
A common table expression gives a query result a name within one SQL statement. It can make a complex report readable by naming populations and intermediate calculations before the final SELECT. That name is not a persistent table, and it does not by itself promise a cached result, a particular scan count, or a sequence of procedural steps.
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Linux overcommit budgets virtual-memory commitments
Linux overcommit policy controls admission of certain virtual-memory commitments. It is separate from allocating resident physical pages, choosing an OOM victim, and enforcing a container’s memory limit. A successful allocation can precede physical demand, but that does not make all allocations free or guarantee that later accesses will succeed under every resource constraint.
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A CronJob turns a schedule into Jobs
A CronJob combines a Job template with a recurring schedule. The CronJob controller creates Jobs; each Job manages the Pods that perform the work. A run can involve retries, replacement Pods, or parallel workers, depending on the Job specification. There need not be a dedicated application process waiting between runs, although completed Jobs and Pods may remain for inspection.
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EXPLAIN ANALYZE runs the query to show real cost
EXPLAIN describes a PostgreSQL execution plan; EXPLAIN ANALYZE also executes the statement and measures its work. The useful comparison is between estimated rows and observed rows at the same node. Neither number is a verdict by itself: an estimate is a model, while a measurement describes one execution under particular data, cache, concurrency, and instrumentation conditions.
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A bloom filter answers maybe at low cost
A Bloom filter can cheaply rule out membership in the set it represents, while a positive answer means only “possibly present.” That asymmetry depends on correct updates and unchanged hash rules. A stale or corrupted filter can reject a key that exists in the underlying database, even though the ordinary append-only algorithm has no false negatives for inserted items.
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Extended attributes belong to the inode and to a namespace
Extended attributes attach named byte values to filesystem objects outside the ordinary file-content stream. Applications can use the user namespace for small metadata, while other namespaces have kernel, security-module, or privileged semantics. Their usefulness depends on the filesystem, access rules, and transfer tools. A metadata tag is reliable only when the workflow preserves and interprets it according to an explicit contract.
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The CONNECT method opens a raw tunnel
CONNECT asks a proxy to establish a tunnel; it does not make the proxy disappear from the data path. After admission, the proxy still forwards bytes in both directions and owns sockets, buffers, and failure handling. CONNECT itself provides no encryption: HTTPS adds a separately verified TLS session through that tunnel.
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