Comment on GatherPath.single_copy

Hello.

The comment on GatherPath.single_copy is the following.

===
/*
* GatherPath runs several copies of a plan in parallel and collects the
* results. The parallel leader may also execute the plan, unless the
* single_copy flag is set.
*/
typedef struct GatherPath
{
Path path;
Path *subpath; /* path for each worker */
bool single_copy; /* path must not be executed >1x */
} GatherPath;
===

The ">1x" looks to me as a kind of typo but looking the comment
above the struct it came to look as "more than once (or one
copy)". But it seems to me that it would be better to be in
ordinary words.

> bool single_copy; /* path must not be executed multiply */

If anyone feel that it is confusing with a verb form, the
following might be better.

> bool single_copy; /* path must not span on multiple processes */

Since anyway I cannot find a comfortable expression for this, I
attached a patch that does the last one.

regards,

--
Kyotaro Horiguchi
NTT Open Source Software Center