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Use access() to check file existence in GetNewRelFileNode()

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Previous code used BasicOpenFile() and close() just to check for a file
collision, while there is no need to hold open a file descriptor but
that's an overkill here.

Author: Paul Guo
Reviewed-by: Peter Eisentraut, Michael Paquier
Discussion: https://postgr.es/m/CABQrizcUtiHaquxK=d4etBX8GF9kbZB50Nt1gO9_aN-e9SptyQ@mail.gmail.com
This commit is contained in:
Michael Paquier 2018-07-08 18:53:20 +09:00
parent 0903bbdad2
commit 677da8c15d
1 changed files with 4 additions and 11 deletions
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15
src/backend/catalog/catalog.c
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@ -397,7 +397,6 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
{
RelFileNodeBackend rnode;
char *rpath;
int fd;
bool collides;
BackendId backend;
@ -445,12 +444,10 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
/* Check for existing file of same name */
rpath = relpath(rnode, MAIN_FORKNUM);
fd = BasicOpenFile(rpath, O_RDONLY | PG_BINARY);
if (fd >= 0)
if (access(rpath, F_OK) == 0)
{
/* definite collision */
close(fd);
collides = true;
}
else
@ -458,13 +455,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
/*
* Here we have a little bit of a dilemma: if errno is something
* other than ENOENT, should we declare a collision and loop? In
* particular one might think this advisable for, say, EPERM.
* However there really shouldn't be any unreadable files in a
* tablespace directory, and if the EPERM is actually complaining
* that we can't read the directory itself, we'd be in an infinite
* loop. In practice it seems best to go ahead regardless of the
* errno. If there is a colliding file we will get an smgr
* failure when we attempt to create the new relation file.
* practice it seems best to go ahead regardless of the errno. If
* there is a colliding file we will get an smgr failure when we
* attempt to create the new relation file.
*/
collides = false;
}