CLUSTER, using SHARE UPDATE EXCLUSIVE lock? - Mailing list pgsql-hackers

From Jonathan Scher
Subject CLUSTER, using SHARE UPDATE EXCLUSIVE lock?
Date
Msg-id 45E6DB57.6000107@oxado.com
Whole thread Raw
Responses Re: CLUSTER, using SHARE UPDATE EXCLUSIVE lock?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Hello,

CLUSTER uses an ACCESS EXCLUSIVE lock. Why does it forbid concurrent reads?
Florian G. Pflug, on a post ( 
http://archives.postgresql.org/pgsql-hackers/2007-02/msg00081.php ) 
suggested that there were no way to let the old entry until the command 
commit.
I would like Cluster to create a new table, copying old values to this 
one, then delete the old one. This would allow Cluster to work with a 
share update exlusive lock, in order to allow reading the table while 
cluster is working.

How does Cluster actually works? Why making a Cluster command less 
restrictive isn't even in the TO-list?

Best regards,
Jonathan Scher


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