Thread: large object regression tests
I noticed when I was working on a patch quite a while back that there are no regression tests for large object support. I know, large objects are not the most sexy part of the code-base, and I think they tend to be ignored/forgotten most of the time. Which IMHO is all the more reason they should have some regression tests. Otherwise, if someone managed to break them somehow, it is quite likely not to be noticed for quite some time. So in this vein, I have recently found myself with some free time, and a desire to contribute something, and decided this would be the perfect place to get my feet wet without stepping on any toes. I guess what I should ask is, would a patch to add a test for large objects to the regression suite be well received? And, is there any advice for how to go about making these tests? I am considering, and I think that in order to get a real test of the large objects, I would need to load data into a large object which would be sufficient to be loaded into more than one block (large object blocks were 1 or 2K IIRC) so that the block boundary case could be tested. Is there any precedent on where to grab such a large chunk of data from? I was thinking about using an excerpt from a public domain text such as Moby Dick, but on second thought binary data may be better to test things with. My current efforts, and probably the preliminary portion of the final test, involves loading a small amount (less than one block) of text into a large object inline from a sql script and calling the various functions against it to verify that they do what they should. In the course of doing so, I find that it is necessary to stash certain values across statements (large object ids, large object 'handles'), and so far I am using a temporary table to store these. Is this reasonable, or is there a cleaner way to do that? -- Even if you're on the right track, you'll get run over if you just sit there. -- Will Rogers
Jeremy Drake <jeremyd@jdrake.com> writes:
> I noticed when I was working on a patch quite a while back that there are
> no regression tests for large object support.
Yeah, this is bad :-(
> I am considering, and I think that in order to get a real test of the
> large objects, I would need to load data into a large object which would
> be sufficient to be loaded into more than one block (large object blocks
> were 1 or 2K IIRC) so that the block boundary case could be tested. Is
> there any precedent on where to grab such a large chunk of data from?
There's always plain old junk data, eg, repeat('xyzzy', 100000).
I doubt that Moby Dick would expose any unexpected bugs ...
> ... I find that it is necessary to stash certain values across
> statements (large object ids, large object 'handles'), and so far I am
> using a temporary table to store these. Is this reasonable, or is there a
> cleaner way to do that?
I think it's supposed to be possible to use psql variables for that;
if you can manage to test psql variables as well as large objects,
that'd be a double bonus.
regards, tom lane
Hi, Jeremy, Jeremy Drake wrote: > I am considering, and I think that in order to get a real test of the > large objects, I would need to load data into a large object which would > be sufficient to be loaded into more than one block (large object blocks > were 1 or 2K IIRC) so that the block boundary case could be tested. Is > there any precedent on where to grab such a large chunk of data from? You could generate such data on the fly, as part of the test scripts. E. G. a blob of zero bytes, blob of 0xff bytes, a blob of pseudo random data... Markus -- Markus Schaber | Logical Tracking&Tracing International AG Dipl. Inf. | Software Development GIS Fight against software patents in EU! www.ffii.org www.nosoftwarepatents.org
On Tuesday 05 September 2006 02:59, Jeremy Drake wrote: > I am considering, and I think that in order to get a real test of the > large objects, I would need to load data into a large object which would > be sufficient to be loaded into more than one block (large object blocks > were 1 or 2K IIRC) so that the block boundary case could be tested. Is > there any precedent on where to grab such a large chunk of data from? I > was thinking about using an excerpt from a public domain text such as Moby > Dick, but on second thought binary data may be better to test things with. A 5 or 6 megapixel JPEG image. Maybe a photograph of an elephant. -- Lamar Owen Director of Information Technology Pisgah Astronomical Research Institute 1 PARI Drive Rosman, NC 28772 (828)862-5554 www.pari.edu