Answer
MySQL locks the row, updates memory pages, logs changes to redo logs, modifies undo logs for MVCC, and writes binlog entries.
Quick Answer
InnoDB UPDATE internals: 1) Find the row using index or full scan. 2) Acquire exclusive row lock. 3) Write old values to undo log (for rollback and MVCC old-version reads). 4) Write the change to redo log (WAL). 5) Modify the row in the buffer pool (in memory). 6) On COMMIT: flush redo log to disk. Data pages may be written to disk lazily (checkpoint). Secondary indexes also updated.
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SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
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Source: SugharaIQ