Re: ZODB eating CPU but RAM is free

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On Fri, Dec 14, 2018 at 9:54 PM Vlad Oles <[email protected]> wrote:

> On Wednesday, July 19, 2017 at 9:54:05 AM UTC-7, Jim Fulton wrote:
>>
>>
>> One thing to understand is that ZODB doesn't limit memory usage.
>> Ghostifies objects to meet memory settings at certain times like
>> transaction boundaries and when asked to explicitly.  So a transaction that
>> loads a lot of objects can grow ram without bound.  This is why
>> applications that load *lots* of objects should explicitly reduce cache
>> size by calling _p_jar.cacheGC() occasionally.
>>
>
> Does it mean that after a database is finalized (no more writing and thus
> transactions), there is no way to bound its RAM cache size other than
> manually resetting cache (via cacheGC() or cacheMinimize()) after every N
> reads?
>

Define finalized.

When a transaction is committed or a connection closed, the connection's
cache is reduced to it's target size. When a database is closed, the
connections and their memory is freed. (If there are cycles, the Python
garbage collection may take some time to deal with them.)

Jim

-- 
Jim Fulton
http://jimfulton.info

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<div dir=3D"ltr"><br><br><div class=3D"gmail_quote"><div dir=3D"ltr">On Fri=
, Dec 14, 2018 at 9:54 PM Vlad Oles &lt;<a href=3D"mailto:vladyslav.oles@gm=
ail.com">[email protected]</a>&gt; wrote:<br></div><blockquote class=
=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rg=
b(204,204,204);padding-left:1ex"><div dir=3D"ltr">On Wednesday, July 19, 20=
17 at 9:54:05 AM UTC-7, Jim Fulton wrote:<blockquote class=3D"gmail_quote" =
style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);pa=
dding-left:1ex"><div dir=3D"ltr"><br><div><div class=3D"gmail_quote"><div>O=
ne thing to understand is that ZODB doesn&#39;t limit memory usage.=C2=A0 G=
hostifies objects to meet memory settings at certain times like transaction=
 boundaries and when asked to explicitly.=C2=A0 So a transaction that loads=
 a lot of objects can grow ram without bound.=C2=A0 This is why application=
s that load <b>lots</b> of objects should explicitly reduce cache size by c=
alling <font face=3D"monospace, monospace">_p_jar.cacheGC()</font> occasion=
ally. <br></div></div></div></div></blockquote><div><br></div><div>Does it =
mean that after a database is finalized (no more writing and thus transacti=
ons), there is no way to bound its RAM cache size other than manually reset=
ting cache (via cacheGC() or cacheMinimize()) after every N reads?</div></d=
iv></blockquote><div><br></div><div>Define finalized.</div><div><br></div><=
div>When a transaction is committed or a connection closed, the connection&=
#39;s cache is reduced to it&#39;s target size. When a database is closed, =
the connections and their memory is freed. (If there are cycles, the Python=
 garbage collection may take some time to deal with them.)</div><div><br></=
div><div>Jim</div><div><br></div></div>-- <br><div dir=3D"ltr" class=3D"gma=
il_signature">Jim Fulton<br><a href=3D"http://jimfulton.info" target=3D"_bl=
ank">http://jimfulton.info</a><br></div></div>

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