Question about Maria readers/writers

From the MySQL v6 manual:
http://dev.mysql.com/doc/refman/6.0/en/se-maria-concurrency. html

+++++
When using transactional tables, Maria supports a single writer and
multiple readers. The single writer supports both
INSERT and
UPDATE operations.

SELECT

All issued SELECT's are running concurrently. While a SELECT is running,
all writers (INSERT, DELETE, UPDATE) are blocked from using any of the used
tables (ie, they wait for the table to be free before continuing).
+++++

If it does support a single writer and multiple readers, why are the
writers blocked when a Select is running? Shouldn't a single writer be able
to run with concurrent Selects?

Mike


--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe: http://lists.mysql.com/mysql?unsub=gcdmg-mysql-2@m.gmane.org

RE: Question about Maria readers/writers

--_225774c2-a17d-4ae5-9e81-2f685d0ce692_
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable


only if you are implementing INNODB Transactional Storage Engine

MySQL uses table-level locking for MyISAM=2C
MEMORY and MERGE tables=2C
page-level locking for BDB tables=2C and
row-level locking for InnoDB tables.
=20
http://dev.mysql.com/doc/refman/5.0/en/internal-locking.html

Martin=20
______________________________________________=20
Verzicht und Vertraulichkeitanmerkung/Note de d=E9ni et de confidentialit=
=E9
=20
Diese Nachricht ist vertraulich. Sollten Sie nicht der vorgesehene Empfaeng=
er sein=2C so bitten wir hoeflich um eine Mitteilung. Jede unbefugte Weiter=
leitung oder Fertigung einer Kopie ist unzulaessig. Diese Nachricht dient l=
ediglich dem Austausch von Informationen und entfaltet keine rechtliche Bin=
dungswirkung. Aufgrund der leichten Manipulierbarkeit von E-Mails koennen w=
ir keine Haftung fuer den Inhalt uebernehmen.
Ce message est confidentiel et peut =EAtre privil=E9gi=E9. Si vous n'=EAtes=
pas le destinataire pr=E9vu=2C nous te demandons avec bont=E9 que pour sat=
isfaire informez l'exp=E9diteur. N'importe quelle diffusion non autoris=E9e=
ou la copie de ceci est interdite. Ce message sert =E0 l'information seule=
ment et n'aura pas n'importe quel effet l=E9galement obligatoire. =C9tant d=
onn=E9 que les email peuvent facilement =EAtre sujets =E0 la manipulation=
=2C nous ne pouvons accepter aucune responsabilit=E9 pour le contenu fourni=
..




> Date: Fri=2C 22 May 2009 09:32:02 -0500
> To: mysql@lists.mysql.com
> From: mos99@fastmail.fm
> Subject: Question about Maria readers/writers
>=20
> From the MySQL v6 manual:
> http://dev.mysql.com/doc/refman/6.0/en/se-maria-concurrency. html
>=20
> +++++
> When using transactional tables=2C Maria supports a single writer and=20
> multiple readers. The single writer supports both=20
> INSERT and=20
> UPDATE operations.
>=20
> SELECT
>=20
> All issued SELECT's are running concurrently. While a SELECT is running=
,
> all writers (INSERT=2C DELETE=2C UPDATE) are blocked from using any of th=
e used=20
> tables (ie=2C they wait for the table to be free before continuing).
> +++++
>=20
> If it does support a single writer and multiple readers=2C why are the=20
> writers blocked when a Select is running? Shouldn't a single writer be ab=
le=20
> to run with concurrent Selects?
>=20
> Mike=20
>=20
>=20
> --=20
> MySQL General Mailing List
> For list archives: http://lists.mysql.com/mysql
> To unsubscribe: http://lists.mysql.com/mysql?unsub=3Dmgainty@hotmail.c=
om
>=20

____________________________________________________________ _____
Hotmail=AE goes with you.=20
http://windowslive.com/Tutorial/Hotmail/Mobile?ocid=3DTXT_TA GLM_WL_HM_Tutor=
ial_Mobile1_052009=

--_225774c2-a17d-4ae5-9e81-2f685d0ce692_--