Hi, On Thu, Mar 21, 2019 at 3:10 AM Shaun Thomas <shaun.tho...@2ndquadrant.com> wrote:
> > I can't really speak for the discussion related to `storage.sgml`, but > I based my investigation on the existing patch to `create_table.sgml`. > About the only thing I would suggest there is to possibly tweak the > wording. > > * "The compress_tuple_target ... " for example should probably read > "The toast_tuple_target parameter ...". > * "the (blocksize - header)" can drop "the". > * "If the value is set to a value" redundant wording should be rephrased; > "If the specified value is greater than toast_tuple_target, then > we will substitute the current setting of toast_tuple_target instead." > would work. > Thanks Shaun. Attached patch makes these adjustments. > * I'd recommend a short discussion on what negative consequences can be > expected by playing with this value. As an example in my tests, setting > it very high may result in extremely sparse pages that could have an > adverse impact on HOT updates. > Setting compress_tuple_target to a higher value won't be negative because the toast_tuple_target is used for compression anyways when compress_tuple_target is higher than toast_tuple_target. May be some discussion in the paragraph related to toast_tuple_target can be added to explain the negative impact of the high value. I added a small discussion about negative effects of setting compress_tuple_target lower though, per your suggestion. Also added some details in storage.sgml as recommended by Sawada-san. Hope this helps. Thanks, Pavan -- Pavan Deolasee http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
0001-Add-a-table-level-option-to-control-compression.patch
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