SeniorSenior (6–10 yrs)SQLRedisMongoDBAmazonOracleJP Morgan
Isolation levels
Explain READ COMMITTED vs REPEATABLE READ vs SERIALIZABLE with anomalies prevented.
Answers use simple, clear English.
Quick interview answer
READ COMMITTED prevents dirty reads. REPEATABLE READ prevents dirty + non-repeatable reads (phantom handling varies by engine). SERIALIZABLE prevents phantoms too via range locks or SSI.
Detailed answer
READ COMMITTED prevents dirty reads. REPEATABLE READ prevents dirty + non-repeatable reads (phantom handling varies by engine). SERIALIZABLE prevents phantoms too via range locks or SSI. Higher isolation increases blocking/abort rates—pick per use case.
seniorarchitect#transactions#isolation