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List: postgresql-general
Subject: [HACKERS] =?gb2312?B?cG9zdGdyZXMgMSC49ii5siAyILj2KSAgIGNhbiBwZyA5LjYgdmFjdXVtIGZy?= =?gb2312?Q?eeze_
From: xu jian <jamesxu () outlook ! com>
Date: 2016-11-30 16:33:06
Message-ID: MWHPR20MB142177B86D893C946FAFC9A4A18C0 () MWHPR20MB1421 ! namprd20 ! prod ! outlook ! com
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Hello,
Please execute me if I am using the wrong mailing list, but I ask the question \
in pgsql-admin, looks like no one know the answer.
we upgraded our pg db to 9.6, as we know, pg9.6 doesn't need full table scan in \
vacuum freeze.
http://rhaas.blogspot.com/2016/03/no-more-full-table-vacuums.html
so we think if we have run vacuum freeze on the table, and there is no change on \
table which has been vacuum freeze before it should finish super faster.
However, it doesn't look like we expect. the next run of vacuum freeze still take \
long time. Then we run vacuum freeze with verbose. we notice it spends long time on \
scanning index.
it seems even all rows are frozen on the data page, vacuum freeze still needs to scan \
all the index pages. if we drop the index, then vacuum freeze finishes immediately.
Does anyone know if it is true?
Btw, our table is large, and has about 40GB index files. is there anyway to make the \
vacuum freeze faster in this case?
Thanks for the help.
James
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<div id="divtagdefaultwrapper" \
style="font-size:12pt;color:#000000;font-family:Calibri,Arial,Helvetica,sans-serif;" \
dir="ltr"> <p></p>
<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: \
16px;">Hello,</p> <p style="font-family: Calibri, Arial, Helvetica, sans-serif; \
font-size: 16px;"> Please execute me if I am using the \
wrong mailing list, but I ask the question in pgsql-admin, looks like no one \
know the answer. </p> <p style="font-family: Calibri, Arial, Helvetica, \
sans-serif; font-size: 16px;"><br> </p>
<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">we \
upgraded our pg db to 9.6, as we know, pg9.6 doesn't need full table scan in \
vacuum freeze. </p> <p style="font-family: Calibri, Arial, Helvetica, \
sans-serif; font-size: 16px;"><a \
href="http://rhaas.blogspot.com/2016/03/no-more-full-table-vacuums.html" \
target="_blank" class="x_OWAAutoLink" id="LPlnk216813" \
previewremoved="true">http://rhaas.blogspot.com/2016/03/no-more-full-table-vacuums.html</a><br>
</p>
<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;"><br>
</p>
<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">so we \
think if we have run vacuum freeze on the table, and there is no change on table \
which has been vacuum freeze before it should finish super \
faster. </p> <p style="font-family: Calibri, Arial, Helvetica, sans-serif; \
font-size: 16px;"><br> </p>
<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: \
16px;">However, it doesn't look like we expect. the next run of vacuum freeze still \
take long time. Then we run vacuum freeze with verbose. we notice it spends \
long time on scanning index. </p> <p style="font-family: Calibri, Arial, \
Helvetica, sans-serif; font-size: 16px;">it seems even all rows are frozen on the \
data page, vacuum freeze still needs to scan all the index pages. if we drop the \
index, then vacuum freeze finishes immediately. </p> <p style="font-family: \
Calibri, Arial, Helvetica, sans-serif; font-size: 16px;"><br> </p>
<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">Does \
anyone know if it is true? </p> <p style="font-family: Calibri, Arial, \
Helvetica, sans-serif; font-size: 16px;"><br> </p>
<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">Btw, \
our table is large, and has about 40GB index files. <span \
style="font-family: Calibri, Arial, Helvetica, sans-serif, "Apple Color \
Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", \
"Android Emoji", EmojiSymbols;">is there anyway to make the vacuum freeze \
faster in this case?</span></p> <p style="font-family: Calibri, Arial, Helvetica, \
sans-serif; font-size: 16px;"><br> </p>
<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: \
16px;">Thanks for the help.</p> <p style="font-family: Calibri, Arial, Helvetica, \
sans-serif; font-size: 16px;"><br> </p>
<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: \
16px;">James</p> <br>
<p></p>
</div>
</body>
</html>
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