- 02 4月, 2016 1 次提交
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由 Noah Misch 提交于
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- 02 3月, 2016 1 次提交
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由 Robert Haas 提交于
The new bit indicates whether every tuple on the page is already frozen. It is cleared only when the all-visible bit is cleared, and it can be set only when we vacuum a page and find that every tuple on that page is both visible to every transaction and in no need of any future vacuuming. A future commit will use this new bit to optimize away full-table scans that would otherwise be triggered by XID wraparound considerations. A page which is merely all-visible must still be scanned in that case, but a page which is all-frozen need not be. This commit does not attempt that optimization, although that optimization is the goal here. It seems better to get the basic infrastructure in place first. Per discussion, it's very desirable for pg_upgrade to automatically migrate existing VM forks from the old format to the new format. That, too, will be handled in a follow-on patch. Masahiko Sawada, reviewed by Kyotaro Horiguchi, Fujii Masao, Amit Kapila, Simon Riggs, Andres Freund, and others, and substantially revised by me.
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- 03 1月, 2016 1 次提交
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由 Bruce Momjian 提交于
Backpatch certain files through 9.1
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- 24 5月, 2015 1 次提交
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由 Bruce Momjian 提交于
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- 13 5月, 2015 1 次提交
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由 Andres Freund 提交于
The new function allows to estimate bloat and other table level statics in a faster, but approximate, way. It does so by using information from the free space map for pages marked as all visible in the visibility map. The rest of the table is actually read and free space/bloat is measured accurately. In many cases that allows to get bloat information much quicker, causing less IO. Author: Abhijit Menon-Sen Reviewed-By: Andres Freund, Amit Kapila and Tomas Vondra Discussion: 20140402214144.GA28681@kea.toroid.org
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