Peter T Mount wrote:
> Quoting Joe Conway <joseph.conway@home.com>:
>
> > TEXT is a datatype which stores character data of unspecified length (up
> > to
> > the max value of a 4 byte integer in length, although I've seen
> > comments
> > indicating that the practical limit is closer to 1 GB -- not sure why).
>
> It may be something to do with the 1Gb splitting of the physical files
> representing a table... Unless it changed recently, a table was split over
> multiple files at the 1Gb mark.
No, it's because the upper two bits of the variable size field are used as flags.
But in practice there are other limits that force you to keep the objects you throw into text or bytea fields alot
smaller. When your INSERT query is received, parsed, planned and a heap tuple created, there are at least
fourcopies of that object in the backends memory. How much virtual memory does your OS support for one single
process?
And by the way, TOAST is not only used for character data types. All variable size data types in the base
system are toastable. Well, arrays might be considered sort of pop-tarts here, but anyway, they get toasted.
Jan
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