On 29 August 2017 at 07:58, Simon Riggs <si...@2ndquadrant.com> wrote: > On 26 August 2017 at 05:40, Mark Kirkwood <mark.kirkw...@catalyst.net.nz> > wrote: >> On 26/08/17 12:18, Simon Riggs wrote: >> >>> On 25 August 2017 at 20:53, Tom Lane <t...@sss.pgh.pa.us> wrote: >>>> >>>> Greg Stark <st...@mit.edu> writes: >>>>> >>>>> I think this is a particularly old piece of code and we're lucky the >>>>> default heuristics have served well for all this time because I doubt >>>>> many people fiddle with these storage attributes. The time may have >>>>> come to come up with a better UI for the storage attributes because >>>>> people are doing new things (like json) and wanting more control over >>>>> this heuristic. >>>> >>>> Yeah, I could get behind a basic rethinking of the tuptoaster control >>>> knobs. I'm just not in love with Simon's specific proposal, especially >>>> not if we can't think of a better name for it than "MAINU". >>> >>> Extended/External would be just fine if you could set the toast >>> target, so I think a better suggestion would be to make "toast_target" >>> a per-attribute option . >>> >> >> +1, have thought about this myself previously....thank you for bringing it >> up! > > OK, so table-level option for "toast_tuple_target", not attribute-level option > > The attached patch and test shows this concept is useful and doesn't > affect existing data. > > For 4x 4000 byte rows: > * by default we use 1 heap block and 3 toast blocks > * toast_tuple_target=4080 uses 2 heap blocks and 0 toast blocks
New patch, v2, since one line in the docs failed to apply because of recent changes. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
toast_tuple_target.v2.patch
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