Takahiro, > PostgreSQL can treat variable-length data flexibly, but therefore > it consumes more spaces if we store short data. Headers of > variable-length types use 4 bytes regardless of the data length. > > My idea is to change the header itself to variable-length. > In order to reduce the size of short data, I wrote a patch to encode > lengths into the first several bits of structure. Also, the alignments > of the types were changed to 'char' from 'int'. > > I know my patch is still insufficient, for example, the types cannot > be TOASTed. But I guess this compression works well for short text.
Hmmm. Seems like these would be different data types from the standard ones we deal with. I can see the value for data warehousing, for example. Wouldn't this require creating, for example, a SHORTTEXT type? Or were you planning this to handle VARCHAR(6) and the like? If so, how would we deal with users who change the length via ALTER TABLE? -- Josh Berkus Aglio Database Solutions San Francisco ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
