Hi,
This sentence:
"SERIALIZABLE: This is the strictest isolation level, Which enforces
transaction serialization. Date accessed in the context of a
serializable transaction can not be accessed by any other transaction."
Regards
W dniu 10.03.2014 21:07, [email protected] pisze:
Hi,
Where do you see info that serializable transaction lock selected
records? At that link i do not see info about this.
Regards,
Karol Bieniaszewski
----- Reply message -----
Od: "Łukasz Bączek" <[email protected]>
Do: <[email protected]>
Temat: [firebird-support] The difference in queries
Data: pon., mar 10, 2014 15:14
Hi,
Ok, but the first question is in SERIALIZABLE transactions and
therefore, according to this:
http://www.firebirdsql.org/manual/isql-transactions.html
is blocked because the query in a transaction with SERIALIZABLE
isolation are blocked automatically, so what's the difference?
Regards
W dniu 10.03.2014 06:13, [email protected] pisze:
Hi,
In first query you have no lock. In second you have lock on selected
records. First query can be run by different users without any lock.
After select from second query user acuire lock on selected records
Regards,
Karol Bieniaszewski
----- Reply message -----
Od: "Łukasz Bączek" <[email protected]>
Do: <[email protected]>
Temat: [firebird-support] The difference in queries
Data: niedz., mar 9, 2014 21:33
Hi,
Inquiries made at isolation level SERIALIZABLE are automatically
blocked
So, for example, by performing a SQL query :
"SELECT * FROM (SELECT sesje.id_sesje , sesje.numer , sesje.data ,
sesje.rozpatrzona , osoby.imie | | ' ' | | osoby.nazwisko chairman AS
FROM LEFT JOIN sessions sesje_eksperci ON sesje.id_sesje =
sesje_eksperci.id_sesje AND sesje_eksperci.przewodniczacy = 1 LEFT JOIN
person ON osoby.id_osoby = sesje_eksperci.id_osoby sesje.data ORDER BY
ASC) WHERE sessions id_sesje = 12 "
I have done automatically blockade record , right?
So what will be different query:
"SELECT * FROM (SELECT sesje.id_sesje , sesje.numer , sesje.data ,
sesje.rozpatrzona , osoby.imie | | ' ' | | osoby.nazwisko chairman AS
FROM LEFT JOIN sessions sesje_eksperci ON sesje.id_sesje =
sesje_eksperci.id_sesje AND sesje_eksperci.przewodniczacy = 1 LEFT JOIN
person ON osoby.id_osoby = sesje_eksperci.id_osoby sesje.data ORDER BY
ASC) WHERE sessions id_sesje = 12 FOR UPDATE WITH LOCK "
because both query blocks record .
Regards
