From db5b49cdd4f481828b227f03b373fbc9bde4301a Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Mon, 19 Aug 2013 17:48:17 -0400
Subject: [PATCH] Fix removal of files in pgstats directories
Instead of deleting all files in stats_temp_directory and the permanent
directory on a crash, only remove those files that match the pattern of
files we actually write in them, to avoid possibly clobbering existing
unrelated contents of the temporary directory. Per complaint from Jeff
Janes, and subsequent discussion, starting at message
CAMkU=1z9+7RsDODnT4=cDFBRBp8wYQbd_qsLcMtKEf-oFwuOdQ@mail.gmail.com
Also, fix a bug in the same routine to avoid removing files from the
permanent directory twice (instead of once from that directory and then
from the temporary directory), also per report from Jeff Janes, in
message
CAMkU=1wbk947=-pAosDMX5VC+sQw9W4ttq6RM9rXu=MjNeEQKA@mail.gmail.com
---
src/backend/postmaster/pgstat.c | 33 ++++++++++++++++++++++++++++-----
1 file changed, 28 insertions(+), 5 deletions(-)
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index dac5bca78aa..f42f1839c22 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -562,15 +562,37 @@ pgstat_reset_remove_files(const char *directory)
struct dirent *entry;
char fname[MAXPGPATH];
- dir = AllocateDir(pgstat_stat_directory);
- while ((entry = ReadDir(dir, pgstat_stat_directory)) != NULL)
+ dir = AllocateDir(directory);
+ while ((entry = ReadDir(dir, directory)) != NULL)
{
- if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
+ int nitems;
+ Oid tmp_oid;
+ char tmp_type[8];
+ char tmp_rest[2];
+
+ if (strncmp(entry->d_name, ".", 2) == 0 ||
+ strncmp(entry->d_name, "..", 3) == 0)
continue;
- /* XXX should we try to ignore files other than the ones we write? */
+ /*
+ * Skip directory entries that don't match the file names we write.
+ * See get_dbstat_filename for the database-specific pattern.
+ */
+ nitems = sscanf(entry->d_name, "db_%u.%5s%1s",
+ &tmp_oid, tmp_type, tmp_rest);
+ if (nitems != 2)
+ {
+ nitems = sscanf(entry->d_name, "global.%5s%1s",
+ tmp_type, tmp_rest);
+ if (nitems != 1)
+ continue;
+ }
+
+ if (strncmp(tmp_type, "tmp", 4) != 0 &&
+ strncmp(tmp_type, "stat", 5) != 0)
+ continue;
- snprintf(fname, MAXPGPATH, "%s/%s", pgstat_stat_directory,
+ snprintf(fname, MAXPGPATH, "%s/%s", directory,
entry->d_name);
unlink(fname);
}
@@ -3627,6 +3649,7 @@ get_dbstat_filename(bool permanent, bool tempname, Oid databaseid,
{
int printed;
+ /* NB -- pgstat_reset_remove_files knows about the pattern this uses */
printed = snprintf(filename, len, "%s/db_%u.%s",
permanent ? PGSTAT_STAT_PERMANENT_DIRECTORY :
pgstat_stat_directory,
--
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