+++
date = "2015-11-23T17:00:57+03:00"
author = "Alan Orth"
title = "November, 2015"
tags = ["notes"]
image = "../images/bg.jpg"

+++
## 2015-11-22

- CGSpace went down
- Looks like DSpace exhausted its PostgreSQL connection pool
- Last week I had increased the limit from 30 to 60, which seemed to help, but now there are many more idle connections:

```
$ psql -c 'SELECT * from pg_stat_activity;' | grep idle | grep -c cgspace
78
```

- For now I have increased the limit from 60 to 90, run updates, and rebooted the server

## 2015-11-24

- CGSpace went down again
- Getting emails from uptimeRobot and uptimeButler that it's down, and Google Webmaster Tools is sending emails that there is an increase in crawl errors
- Looks like there are still a bunch of idle PostgreSQL connections:

```
$ psql -c 'SELECT * from pg_stat_activity;' | grep idle | grep -c cgspace
96
```

- For some reason the number of idle connections is very high since we upgraded to DSpace 5

## 2015-11-25

- Troubleshoot the DSpace 5 OAI breakage caused by nginx routing config
- The OAI application requests stylesheets and javascript files with the path `/oai/static/css`, which gets matched here:

```
# static assets we can load from the file system directly with nginx
location ~ /(themes|static|aspects/ReportingSuite) {
    try_files $uri @tomcat;
...
```

- The document root is relative to the xmlui app, so this gets a 404—I'm not sure why it doesn't pass to `@tomcat`
- Anyways, I can't find any URIs with path `/static`, and the more important point is to handle all the static theme assets, so we can just remove `static` from the regex for now (who cares if we can't use nginx to send Etags for OAI CSS!)
- Also, I noticed we aren't setting CSP headers on the static assets, because in nginx headers are inherited in child blocks, but if you use `add_header` in a child block it doesn't inherit the others
- We simply need to add `include extra-security.conf;` to the above location block (but research and test first)
- We should add WOFF assets to the list of things to set expires for:

```
location ~* \.(?:ico|css|js|gif|jpe?g|png|woff)$ {
```

- We should also add `aspects/Statistics` to the location block for static assets (minus `static` from above):

```
location ~ /(themes|aspects/ReportingSuite|aspects/Statistics) {
```

- Need to check `/about` on CGSpace, as it's blank on my local test server and we might need to add something there
- CGSpace has been up and down all day due to PostgreSQL idle connections (current DSpace pool is 90):

```
$ psql -c 'SELECT * from pg_stat_activity;' | grep idle | grep -c cgspace
93
```

- I looked closer at the idle connections and saw that many have been idle for hours (current time on server is `2015-11-25T20:20:42+0000`):

```
$ psql -c 'SELECT * from pg_stat_activity;' | less -S
datid | datname  |  pid  | usesysid | usename  | application_name | client_addr | client_hostname | client_port |         backend_start         |          xact_start           |
-------+----------+-------+----------+----------+------------------+-------------+-----------------+-------------+-------------------------------+-------------------------------+---
20951 | cgspace  | 10966 |    18205 | cgspace  |                  | 127.0.0.1   |                 |       37731 | 2015-11-25 13:13:02.837624+00 |                               | 20
20951 | cgspace  | 10967 |    18205 | cgspace  |                  | 127.0.0.1   |                 |       37737 | 2015-11-25 13:13:03.069421+00 |                               | 20
...
```

- There is a relevant Jira issue about this: https://jira.duraspace.org/browse/DS-1458
- It seems there is some sense changing DSpace's default `db.maxidle` from unlimited (-1) to something like 8 (Tomcat default) or 10 (Confluence default)
- Change `db.maxidle` from -1 to 10, reduce `db.maxconnections` from 90 to 50, and restart postgres and tomcat7
- Also redeploy DSpace Test with a clean sync of CGSpace and mirror these database settings there as well
- Also deploy the nginx fixes for the `try_files` location block as well as the expires block

## 2015-11-26

- CGSpace behaving much better since changing `db.maxidle` yesterday, but still two up/down notices from monitoring this morning (better than 50!)
- CCAFS colleagues mentioned that the REST API is very slow, 24 seconds for one item
- Not as bad for me, but still unsustainable if you have to get many:

```
$ curl -o /dev/null -s -w %{time_total}\\n https://cgspace.cgiar.org/rest/handle/10568/32802?expand=all
8.415
```

- Monitoring e-mailed in the evening to say CGSpace was down
- Idle connections in PostgreSQL again:

```
$ psql -c 'SELECT * from pg_stat_activity;' | grep cgspace | grep -c idle
66
```

- At the time, the current DSpace pool size was 50...
- I reduced the pool back to the default of 30, and reduced the `db.maxidle` settings from 10 to 8

## 2015-11-29

- Still more alerts that CGSpace has been up and down all day
- Current database settings for DSpace:

```
db.maxconnections = 30
db.maxwait = 5000
db.maxidle = 8
db.statementpool = true
```

- And idle connections:

```
$ psql -c 'SELECT * from pg_stat_activity;' | grep cgspace | grep -c idle
49
```

- Perhaps I need to start drastically increasing the connection limits—like to 300—to see if DSpace's thirst can ever be quenched
- On another note, SUNScholar's notes suggest adjusting some other postgres variables: http://wiki.lib.sun.ac.za/index.php/SUNScholar/Optimisations/Database
- This might help with REST API speed (which I mentioned above and still need to do real tests)