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Re: Connections hang indefinitely while taking a gin index's LWLockbuffer_content lock(PG10.7) - Mailing list pgsql-hackers

From Alexander Korotkov
Subject Re: Connections hang indefinitely while taking a gin index's LWLockbuffer_content lock(PG10.7)
Date
Msg-id CAPpHfduQdEVcZrJhceU01zfa5dYrw8oc5f1m8NNGSYM8VFS3GA@mail.gmail.com
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In response to Connections hang indefinitely while taking a gin index's LWLockbuffer_content lock(PG10.7)  (chenhj <chjischj@163.com>)
Responses Re: Connections hang indefinitely while taking a gin index's LWLockbuffer_content lock(PG10.7)
Re: Connections hang indefinitely while taking a gin index's LWLockbuffer_content lock(PG10.7)
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Hi!

Thank you for reporting.

On Sun, Sep 29, 2019 at 11:17 AM chenhj <chjischj@163.com> wrote:
> Does the locking order of autovacuum process(root->right->left) correct? While insert process lock gin buffer by
orderof bottom->top and left->right.
 
>
> 1. vacuum(root->right->left):

Starting from root seems OK for me, because vacuum blocks all
concurrent inserts before doing this.  But this needs to be properly
documented in readme.

Locking from right to left is clearly wrong.  It could deadlock with
concurrent ginStepRight(), which locks from left to right.  I expect
this happened in your case.  I'm going to reproduce this and fix.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company

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