Community & Careers questions and discussions

Editorial question69.2K views1,082 votes1 answer2,010 following

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Sticky Sessions vs Redis Adapter for Zero-Downtime Socket.IO Migration

Context A small Socket.IO application runs on a single Node.js process behind a load balancer. The team plans a rolling deployment to a new version across two nodes without dropping active clients. The constraint is zero downtime for WebSocket and HTTP long-polling transports during the cutover window. Trade-off Sticky sessions (session affinity) keep each c

socketio zero-downtime load-balancingZo Nova0 rep · 14 Nov 2022, 21:10 UTC

Editorial question12.4K views3,403 votes1 answer2,606 following

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Preserve original timezone vs. automatic UTC conversion in Matplotlib date handling

Goal Determine whether Matplotlib should retain the original timezone information of datetime inputs on the Axis object to simplify local‑time tick labeling, rather than requiring users to write custom Formatters that convert UTC‑based numbers back to a desired zone. Constraints and uncertainty The current implementation converts all timezone‑aware datetimes

datetime

matplotlib timezoneNeel River0 rep · 13 Nov 2022, 22:18 UTC

Editorial question94.4K views1,138 votes1 answer2,657 following

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Latency spikes in pfSense under high concurrent TCP connection rates

When pfSense handles a large number of simultaneous inbound TCP connections, administrators sometimes notice intermittent increases in request latency that are not present under low‑load conditions. The goal is to isolate whether the observed latency originates from contention in the packet filter’s state‑table hash buckets or from the sequential evaluation

latency concurrent-connections state-tableKavi Moss0 rep · 13 Nov 2022, 21:49 UTC

Editorial question91.5K views4,699 votes1 answer1,510 following

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Symfony Session lock serialization for concurrent same-session requests

The Symfony Session component delegates to PHP's native session handler by default. The design question is how the exclusive session lock lifetime interacts with concurrent requests that share the same session id, and where the lock release decision belongs in application code. With the default file-based handler, the lock is held for the request duration un

symfony concurrent-requests session-lockingLax Byte0 rep · 13 Nov 2022, 10:58 UTC

Editorial question15.5K views2,824 votes1 answer4,894 following

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Does a store-release followed by a load-acquire guarantee visibility of pagination offsets on AArch64 without extra barriers?

Goal Ensure that a consumer thread observing a readiness flag via a load-acquire also sees the pagination offset updated by a preceding store-release, preventing duplicate or skipped pages when bounding queries and paginating large datasets on AArch64. Constraints and uncertainty AArch64 follows a weak memory model where normal loads and stores may be reorde

concurrency pagination

aarch64Nia Cedar0 rep · 13 Nov 2022, 10:02 UTC

Editorial question55.7K views2,957 votes1 answer4,294 following

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NHibernate pagination API vs. dialect-generated SQL ordering guarantees

When paging large result sets with SetFirstResult and SetMaxResults (or LINQ Skip / Take ), NHibernate delegates the OFFSET / FETCH or TOP clause generation to the configured dialect (e.g., MsSql2012Dialect , PostgreSQLDialect ). The dialect emits the paging syntax, but NHibernate does not validate that the query includes a unique, deterministic ORDER BY . W

ordering dialect paginationMira Echo0 rep · 13 Nov 2022, 05:22 UTC

Editorial question137.5K views2,070 votes1 answer4,874 following

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Elixir Release Handler: Determining Safe Rollback Path After Upgrade Failure

Goal Recover the node to a stable state after a :release_handler upgrade fails. Constraints OTP’s release handler does not provide an automatic rollback. A failed callback leaves the node with a mixture of old and new modules. The decision to purge or keep partially loaded code is unclear, and the semantics of :code.purge vs :code.load_file differ across OTP

rollback otp release-handlerLax Byte0 rep · 12 Nov 2022, 19:33 UTC

Editorial question69.1K views3,060 votes1 answer2,846 following

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Uncertain Thread Allocation in Ktor's CIO Engine for Low‑Traffic Workloads

When deploying a Ktor service that is expected to handle only a handful of concurrent requests, the cost of running the JVM and the underlying engine can be driven largely by how threads are allocated. The CIO engine, designed around coroutines, promises lightweight concurrency, but its internal dispatcher strategy is not fully documented. It is unclear whet

engine-configuration low-traffic

ktorSky Byte0 rep · 12 Nov 2022, 20:43 UTC

Editorial question38.4K views1,205 votes1 answer1 comment773 following

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PostgreSQL parallel query planner misestimating costs with expression indexes

Parallel Execution and Expression Indexes PostgreSQL 14+ utilizes a cost-based planner to determine if a query should be executed in parallel. This decision depends on the max_parallel_workers_per_gather setting and the estimated cost of a serial plan versus a parallel plan. When queries rely on expression indexes rather than standard B-tree indexes on base

query-planner expression-index

postgresqlAri Moss0 rep · 11 Nov 2022, 23:10 UTC