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Sep 16, 2026A Composite Index Is Built, but the Query Uses Only the Last Column and Still Does a Full Table Scan—Should You Add a Single-Column Index?When a composite index is used but the query includes only the last column, SQL may not us ...View details
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Sep 15, 2026Cache expiration times are all set the same, and the database suddenly maxes out at 1 a.m.—is it because the keys expire at the same time?When cache keys share the same expiration time, they expire together, requests fall back t ...View details
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Sep 14, 2026Order amounts stored as decimals—reconciliation always off by a few cents—is floating-point precision the culprit?Order amounts stored as decimals look fine per transaction, but at month-end reconciliatio ...View details
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Sep 13, 2026Upload folders ship with code and images are lost—should files be stored locally or in object storage?User-uploaded images keep piling up, disk alerts and lost files on release often appear to ...View details
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Sep 12, 2026Saved Just Now but the Detail Page Still Shows the Old Record — Does Read-Write Splitting Mean Every Read Has to Go to the Primary?A record saved just now, yet the detail page still reads the old one — usually the read l ...View details
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Sep 11, 2026Scheduled Jobs Run Fine on One Machine but Duplicate on Multiple Servers — Where Should You Stop Them?When a scheduled job runs fine on a single machine but duplicates across multiple servers, ...View details
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Sep 10, 2026Auto-increment primary keys are convenient when a table first goes live — how much trouble is it to change them on the day you actually shard?An auto-increment primary key really is convenient when a table first goes live, but when ...View details
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Sep 9, 2026Why did APIs get slower after increasing the database connection pool, and what is the appropriate connection count?After increasing the database connection pool, APIs may become slower. In most cases, the ...View details
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Sep 8, 2026When an API upgrade breaks old clients, should you keep the old API?After an API upgrade, old clients may fail. Don't rush users to update; first identify whi ...View details
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Sep 8, 2026Why do APIs intermittently time out, restart helps temporarily, but logs show no errors?APIs intermittently time out, restart helps for a while, but logs show no obvious errors. ...View details
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Sep 7, 2026Should the backend set a missing field to empty when the frontend omits it in an update request?When an update API receives a request without a certain field, do not default to updating ...View details
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Sep 6, 2026Database field missing in production but works in test: did the migration script fail to run?A field missing in production but present in test does not necessarily mean someone forgot ...View details
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Sep 5, 2026API Signature Verification Keeps Failing? Where to Check First When Integrating with a Third Party?Signature verification failures are usually not due to incorrect algorithm implementation, ...View details
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Sep 4, 2026List API Fetches Tens of Thousands of Records at Once, Frontend Needs Pagination and Totals—How to Return Data Without Lag?When a list API is slow, don't rush to add cache. First, clarify the relationship between ...View details
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Sep 3, 2026What percentage of traffic should a canary release start with? How long without anomalies should you wait before switching to full?There is no fixed formula for switching from canary release to full rollout. A common prac ...View details
