Oracle DB Transactions — Phantom Read

Transaction T1 reads a set of data items satisfying some <search condition>. Transaction T2 then creates data items that satisfy T1 ’s <search condition> and commits. If T1 then repeats its read with the same <search condition>, it gets a set of data items different from the first read.

r1[P]…w2[y in P]…c2…r1[P]…c1

Phantom read occurs in “READ COMMITTED” isolation level in Oracle

Phantom read does not occur in “SERIALIZABLE” isolation level in Oracle

💡Serializable isolation level in Oracle is actually a “Snapshot Isolation”

Transaction 1

Transaction 2