[Solved] In PostgreSQL, what characteristic best describes the REPEATABLE READ isolation level? — Ans: It ensures that all SELECT queries within a transaction see a consistent... | PostgreSQL

PostgreSQL - Transactions and Concurrency

In PostgreSQL, what characteristic best describes the REPEATABLE READ isolation level?

AIt locks all rows read to prevent any concurrent updates.

BIt allows dirty reads but prevents non-repeatable reads.

CIt ensures that all SELECT queries within a transaction see a consistent snapshot of the database.

DIt guarantees full serializability of concurrent transactions.

Step-by-Step Solution

Solution:

Step 1: Understand REPEATABLE READ
REPEATABLE READ provides a consistent snapshot for all reads within a transaction.
Step 2: Analyze options
It ensures that all SELECT queries within a transaction see a consistent snapshot of the database. correctly states the snapshot behavior; B is incorrect because dirty reads are not allowed; C is wrong as it does not lock all rows read; D is false because SERIALIZABLE isolation is stricter.
Final Answer:
It ensures that all SELECT queries within a transaction see a consistent snapshot of the database. -> Option C
Quick Check:
Snapshot isolation means repeatable reads [OK]

Quick Trick: REPEATABLE READ = consistent snapshot for all reads [OK]

Common Mistakes:

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In PostgreSQL, what characteristic best describes the REPEATABLE READ isolation level?