On Sat, Oct 5, 2013 at 6:39 AM, Stephen Frost <sfr...@snowman.net> wrote:
> * Robert Haas (robertmh...@gmail.com) wrote: > > On Fri, Oct 4, 2013 at 11:28 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > > > David Rowley <dgrowle...@gmail.com> writes: > > >> Here's a small patch which greatly increases the speed of > > >> pg_dump --column-inserts. > > > > > > The reason why no one's paid any attention to the speed of that code > path > > > is that if you care about dump/restore speed, you should be using the > COPY > > > code paths instead. Is it really worth adding code and complexity to > > > pg_dump for this? > > > > One possible reason to care about this is if you're trying to move > > data to another database. The INSERT format is more portable. > > > > Also, this isn't really adding any net code or complexity AFAICS. > > Agreed- this looks more like a "gee, that makes a lot of sense" than a > "wow, that's way more complicated". Not a whole lot of point in > building up a known-to-be-constant string on every iteration of the > loop. > > These words made me think that the changes I made were not quite enough to satisfy this what you said. I understand that most people won't use the --column-inserts feature, but that's not really a great reason to have not very clever and wasteful code in there. This fruit was so low hanging it was pretty much touching the ground, so I couldn't resist fixing it when I saw it. The attached revised patch goes a little further and prepares everything that is constant on processing the first row, this now includes the "INSERT INTO tablename " part. I don't think the changes make the code any harder to read, the code which builds the staticStmt fits into my small laptop screen. The timings with my benchmark look something like: Unpatched: 9200 ms Version 0.1: 5700 ms Version 0.2: 5250 ms So it does shave off a bit more, for what it's worth. David > Thanks, > > Stephen >
pg_dump_colinsert_v0.2.patch
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