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From: SAMEER KUMAR <sameer.kasi200x@gmail.com>
Date: Fri, 25 Oct 2024 20:09:45 +0800
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 <CAGPeHmiuURaY4K=Kj6uktbiKBt-cGPFpH-2Vvb90ZgnB0TAXwA@mail.gmail.com>
Subject: Re: lwlock:LockManager wait_events
To: James Pang <jamespang886@gmail.com>
Cc: pgsql-performance@lists.postgresql.org
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On Fri, 25 Oct 2024, 14:36 James Pang, <jamespang886@gmail.com> wrote:

> experts,
>     we faced into a lot of  lwlock:LockManager wait-events , all of these
> queries are "select ..." ,  there are other several session are doing DML,
> insert/update/delete on same table.   Did these DML transactions holding
> "transactionid" and "tuple" lock blocking "select" on lwlock:LockManager ?
>


Which version of PostgreSQL?
Are these all same query or variant of same query (with different
parameters)?

What's the schema (you can redact column names) for the tables involved in
the select query which is blocked/waiting on lock_manager?


> Thanks,
>
> James
>

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<div dir=3D"auto"><div><br><br><div class=3D"gmail_quote"><div dir=3D"ltr" =
class=3D"gmail_attr">On Fri, 25 Oct 2024, 14:36 James Pang, &lt;<a href=3D"=
mailto:jamespang886@gmail.com">jamespang886@gmail.com</a>&gt; wrote:<br></d=
iv><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left=
:1px #ccc solid;padding-left:1ex"><div dir=3D"ltr">experts,<div>=C2=A0 =C2=
=A0 we faced into a lot of=C2=A0 lwlock:LockManager wait-events , all of th=
ese queries=C2=A0are &quot;select ...&quot; ,=C2=A0 there are other several=
 session are doing DML, insert/update/delete on same table.=C2=A0 =C2=A0Did=
 these DML transactions holding &quot;transactionid&quot; and &quot;tuple&q=
uot; lock blocking=C2=A0&quot;select&quot; on lwlock:LockManager ?=C2=A0=C2=
=A0</div></div></blockquote></div></div><div dir=3D"auto"><br></div><div di=
r=3D"auto"><br></div><div dir=3D"auto">Which version of PostgreSQL?</div><d=
iv dir=3D"auto">Are these all same query or variant of same query (with dif=
ferent parameters)?=C2=A0</div><div dir=3D"auto"><br></div><div dir=3D"auto=
">What&#39;s the schema (you can redact column names) for the tables involv=
ed in the select query which is blocked/waiting on lock_manager?=C2=A0</div=
><div dir=3D"auto"><br></div><div dir=3D"auto"><div class=3D"gmail_quote"><=
blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px=
 #ccc solid;padding-left:1ex"><div dir=3D"ltr"><div><br></div><div>Thanks,<=
/div><div><br></div><div>James</div></div>
</blockquote></div></div></div>

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