问题
I use postgres from homebrew in my OS X, but when I reboot my system, sometimes the postgres doesn\'t start after the reboot, and so I manually tried to start it with postgres -D /usr/local/var/postgres, but then the error occurred with the following message: FATAL: could not open directory \"pg_tblspc\": No such file or directory.
The last time it occurred, I couldn\'t get it to the original state, so I decided to uninstall the whole postgres system and then re-installed it and created users, tables, datasets, etc... It was so disgusting, but it frequently occurs on my system, say once in a few months.
So why does it lose the pg_tblspc file frequently? And is there anything that I can do to avoid the loss of the file?
I haven\'t upgraded my homebrew and postgres to the latest version (i.e. I\'ve been using the same version). Also, all the things that I did on the postgres database is delete the table and populate the new data every day. I haven\'t changed the user, password, etc...
EDIT (mbannert): I felt the need to add this, since the thread is the top hit on google for this issue and for many the symptom is different. Homebrewers likely will encounter this error message:
No such file or directory
Is the server running locally and accepting
connections on Unix domain socket \"/tmp/.s.PGSQL.5432\"?
So, if you just experienced this after the Yosemite upgrade you now you\'re covered for now reading this thread.
回答1:
Solved... in part.
Apparently, Installing the latest versions of OS X (e.g. Yosemite or El Capitan) removes some directories in /usr/local/var/postgres.
To fix this you simply recreate the missing directories:
mkdir /usr/local/var/postgres/pg_tblspc
mkdir /usr/local/var/postgres/pg_twophase
mkdir /usr/local/var/postgres/pg_stat
mkdir /usr/local/var/postgres/pg_stat_tmp
mkdir /usr/local/var/postgres/pg_replslot
mkdir /usr/local/var/postgres/pg_snapshots
Or, more concisely (thanks to Nate):
mkdir /usr/local/var/postgres/{pg_tblspc,pg_twophase,pg_stat,pg_stat_tmp,pg_replslot,pg_snapshots}/
Rerunning pg_ctl start -D /usr/local/var/postgres now starts the server normally and, at least for me, without any data loss.
UPDATE
On my system, some of those directories are empty even when Postgres is running. Maybe, as part of some "cleaning" operation, Yosemite removes any empty directories? In any case, I went ahead and created a '.keep' file in each directory to prevent future deletion.
touch /usr/local/var/postgres/{pg_tblspc,pg_twophase,pg_stat,pg_stat_tmp,pg_replslot,pg_snapshots}/.keep
Note: Creating the .keep file in those directories will create some noise in your logfile, but doesn't appear to negatively affect anything else.
回答2:
Donavan's answer is spot on, I just wanted to add that as i did different things with the database (e.g. rake db:test), it went looking for different directories that haven't been mentioned above and would choke when they weren't present, in my case pg_logical/mappings, so you may want to setup a terminal running:
tail -f /usr/local/var/postgres/server.log
and watch it for missing folders while you go thru your typical database activities.
回答3:
This is slightly off-topic but worth noting here as part of the PostgreSQL Yosemite recovery process. I had the same issue as above AND I had an issue with PostgreSQL "seemingly" running in the background so even after adding directories I couldn't restart. I tried using pg_ctl stop -m fast to kill the PostgreSQL server but no luck. I also tried going after the process directly with kill PID but as soon as I did that a PostgreSQL process re-appeared with a different PID.
The key ended up being a .plist file that Homebrew had loaded... The fix for me ended up being:
launchctl unload /Users/me/Library/LaunchAgents/homebrew.mxcl.postgresql92.plist
After that I was able to start PostgreSQL normally.
回答4:
The missing directories need to be present in your PostgreSQL data directory. The default data directory is /usr/local/var/postgres/. If you have set up a different data directory, you need to re-create the missing directories there. If you modified the homebrew-recommended .plist file that starts PostgreSQL, you can find the data directory there:
cat ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
(it's the -D option you started postgres with:)
<key>ProgramArguments</key>
<array>
<string>/usr/local/bin/postgres</string>
<string>-D</string>
<string>/usr/local/pgsql/data</string>
In the example above, you'd create the missing directories in /usr/local/pgsql/data, like so:
cd /usr/local/pgsql/data
mkdir {pg_tblspc,pg_twophase,pg_stat,pg_stat_tmp,pg_replslot,pg_snapshots,pg_logical}
mkdir pg_logical/{snapshots,mappings}
回答5:
Creating the missing directories certainly works but I fixed it by reinititializing postgres db, this is a cleaner approach to avoid future problems.
NOTE: This approach will delete existing databases
$ rm -r /usr/local/var/postgres
$ initdb -D /usr/local/var/postgres
来源：https://stackoverflow.com/questions/25970132/pg-tblspc-missing-after-installation-of-latest-version-of-os-x-yosemite-or-el