Re: Extending varlena - Mailing list pgsql-hackers

From Gregory Williamson
Subject Re: Extending varlena
Date
Msg-id 8B319E5A30FF4A48BE7EEAAF609DB233021F31FE@COMAIL01.digitalglobe.com
Whole thread Raw
In response to Extending varlena  (David Fetter <david@fetter.org>)
List pgsql-hackers
<p><font size="2">David Fetter wrote"<br /><br /> <...><br /> ><br /> > > This'd greatly simplify the<br
/>> > cleanup-dead-objects problem, and we could avoid addressing the<br /> > > permissions problem at all,
sinceregular SQL permissions on the table<br /> > > would serve fine.  But it's not clear what regular SQL fetch
andupdate<br /> > > behaviors should be like for such a thing.  (Fetching or storing the<br /> > > whole
blobvalue is right out, IMHO.)  ISTR hearing of concepts roughly<br /> > > like this in other DBs --- does it
ringa bell for anyone?<br /> ><br /> > Informix has some pretty good blob-handling:<br /> ><br /> > <a
href="http://publib.boulder.ibm.com/infocenter/idshelp/v10/index.jsp?topic=/com.ibm.sqlr.doc/sqlrmst101.htm">http://publib.boulder.ibm.com/infocenter/idshelp/v10/index.jsp?topic=/com.ibm.sqlr.doc/sqlrmst101.htm</a><br
/>><br /><br /> Agreed. I used Informix a few years back in a system that scanned both sides of multi-page financial
documents;we stored them in Informix' blobs, which IIRC could be tuned to be given number of bytes. We found that 90%
ofour images fit in a given size and since Informix raw disk access let them move up the whole blob in a single pass,
itwas quite fast, and gave us all the warmth and fuzziness of ACID functionality. But we didn't fetch parts of the BLOB
--metadata lived in its own table. There is/was an Illustra/Informix blade which let you in theory do some processing
ofimages (indexing) but that seems like a very specialized case.<br /><br /> Greg Williamson<br /> Senior DBA<br />
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