问题
Recently, I've started playing around with an old Raspberry Pi 3 b+, and I thought it would be good practice to host a Postgres database on my local network and use it for whatever I want to work through. I understand that running Postgres on a Raspberry Pi with 1GB of memory is not ideal and can take a toll on the SDcard, but I've updated the postgresql.conf file and specified that the data directory path is to utilize a 1TB SSD. Additionally, I've installed zram and log2ram to try and curb some of the overhead on SDcard.
Overview of tech I'm working with:
- Raspberry Pi 3 B+
- Postgres 12
- Ubuntu server 20.04 (no gui, only working from terminal)
- 1TB SSD
Yesterday, I was writing to the Postgres db from a python notebook without any issue, but once I restarted the Raspberry Pi, I was unable to reach the db from DataGrip and would receive the following error from my terminal in Ubuntu:
psql: error: could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
I checked the status of the postgres server and that seemed to be alright...:
● postgresql.service - PostgreSQL RDBMS
Loaded: loaded (/lib/systemd/system/postgresql.service; enabled; vendor preset: enabled)
Active: active (exited) since Thu 2021-01-28 13:34:41 UTC; 20min ago
Process: 1895 ExecStart=/bin/true (code=exited, status=0/SUCCESS)
Main PID: 1895 (code=exited, status=0/SUCCESS)
Jan 28 13:34:41 ubuntu systemd[1]: Starting PostgreSQL RDBMS...
Jan 28 13:34:41 ubuntu systemd[1]: Finished PostgreSQL RDBMS.
This is what is provided in the postgresql-12-main.log:
2021-01-28 13:17:23.344 UTC [1889] LOG: starting PostgreSQL 12.5 (Ubuntu 12.5-0ubuntu0.20.04.1) on aarch64-unknown-linux-gnu, compiled by gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0, 64-bit
2021-01-28 13:17:23.362 UTC [1889] LOG: listening on IPv4 address "0.0.0.0", port 5432
2021-01-28 13:17:23.362 UTC [1889] LOG: listening on IPv6 address "::", port 5432
2021-01-28 13:17:23.365 UTC [1889] LOG: listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
2021-01-28 13:17:23.664 UTC [1899] LOG: database system was shut down at 2021-01-28 01:43:38 UTC
2021-01-28 13:17:24.619 UTC [1899] LOG: could not link file "pg_wal/xlogtemp.1899" to "pg_wal/000000010000000000000002": Operation not permitted
2021-01-28 13:17:24.670 UTC [1899] FATAL: could not open file "pg_wal/000000010000000000000002": No such file or directory
2021-01-28 13:17:24.685 UTC [1889] LOG: startup process (PID 1899) exited with exit code 1
2021-01-28 13:17:24.686 UTC [1889] LOG: aborting startup due to startup process failure
2021-01-28 13:17:24.708 UTC [1889] LOG: database system is shut down
pg_ctl: could not start server
Examine the log output.
Please let me know if you have any questions or if you would like for me to include any additional information. I appreciate any pointers you may have for head ahead of time.
回答1:
This is what the /etc/init.d/postgres file looks like:::
#!/bin/sh
set -e
### BEGIN INIT INFO
# Provides: postgresql
# Required-Start: $local_fs $remote_fs $network $time
# Required-Stop: $local_fs $remote_fs $network $time
# Should-Start: $syslog
# Should-Stop: $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: PostgreSQL RDBMS server
### END INIT INFO
# Setting environment variables for the postmaster here does not work; please
# set them in /etc/postgresql/<version>/<cluster>/environment instead.
[ -r /usr/share/postgresql-common/init.d-functions ] || exit 0
. /usr/share/postgresql-common/init.d-functions
# versions can be specified explicitly
if [ -n "$2" ]; then
versions="$2 $3 $4 $5 $6 $7 $8 $9"
else
get_versions
fi
case "$1" in
start|stop|restart|reload)
if [ "$1" = "start" ]; then
create_socket_directory
fi
if [ -z "`pg_lsclusters -h`" ]; then
log_warning_msg 'No PostgreSQL clusters exist; see "man pg_createcluster"'
exit 0
fi
for v in $versions; do
$1 $v || EXIT=$?
done
exit ${EXIT:-0}
;;
status)
LS=`pg_lsclusters -h`
# no clusters -> unknown status
[ -n "$LS" ] || exit 4
echo "$LS" | awk 'BEGIN {rc=0} {if (match($4, "down")) rc=3; printf ("%s/%s (port %s): %s\n", $1, $2, $3, $4)}; END {exit rc}'
;;
force-reload)
for v in $versions; do
reload $v
done
;;
*)
echo "Usage: $0 {start|stop|restart|reload|force-reload|status} [version ..]"
exit 1
;;
esac
exit 0
回答2:
config file (partly):
#------------------------------------------------------------------------------
# FILE LOCATIONS
#------------------------------------------------------------------------------
# The default values of these variables are driven from the -D command-line
# option or PGDATA environment variable, represented here as ConfigDir.
#data_directory = 'ConfigDir' # use data in another directory
# (change requires restart)
#hba_file = 'ConfigDir/pg_hba.conf' # host-based authentication file
# (change requires restart)
#ident_file = 'ConfigDir/pg_ident.conf' # ident configuration file
# (change requires restart)
# If external_pid_file is not explicitly set, no extra PID file is written.
#external_pid_file = '' # write an extra PID file
# (change requires restart)
/etc/init.d/postgresql (partly):
NOTE: this is from a non-standard installation. YMMV
# Data directory
#PGDATA="/data/db/postgres"
#PGDATA="/data/db/postgres/pgdata"
#PGDATA="/data/db/postgres-12/pgdata"
PGDATA="/data/db/postgres-11/pgdata"
(when upgrading, I tend to keep the commented-out older setting for reference)
Note: the config-file is not edited, every path refers to the ConfigDir (by default)
Additionally, for Postgres on a Pi, I set:
random_page_cost = 1.1
shared_buffers = 128MB
#work_mem = 4MB # keep the low default
effective_cache_size = 3GB # This is for a RaspberryPi-4
# for a Pi-3, I'd use ~700M
来源：https://stackoverflow.com/questions/65938577/why-is-my-postgres-database-working-for-a-while-and-then-not-able-to-start-serv