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doc: clarify text around MVCC example query
Reported-by: marlene.brandstaetter@cargonet.software Discussion: https://postgr.es/m/167765529052.987840.12345375075704447735@wrigleys.postgresql.org Backpatch-through: master
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@ -417,8 +417,8 @@
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does not see effects of those commands on other rows in the database.
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This behavior makes Read Committed mode unsuitable for commands that
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involve complex search conditions; however, it is just right for simpler
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cases. For example, consider updating bank balances with transactions
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like:
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cases. For example, consider transferring $100 from one account
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to another:
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<screen>
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BEGIN;
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@ -427,8 +427,8 @@ UPDATE accounts SET balance = balance - 100.00 WHERE acctnum = 7534;
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COMMIT;
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</screen>
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If two such transactions concurrently try to change the balance of account
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12345, we clearly want the second transaction to start with the updated
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If another transactions concurrently tries to change the balance of account
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7534, we clearly want the second statement to start with the updated
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version of the account's row. Because each command is affecting only a
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predetermined row, letting it see the updated version of the row does
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not create any troublesome inconsistency.
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