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Is there a timeout for idle PostgreSQL connections?
...ement an idle connection reaper. Have a cron job run something like this:
SELECT pg_terminate_backend(pid)
FROM pg_stat_activity
WHERE datname = 'regress'
AND pid <> pg_backend_pid()
AND state = 'idle'
AND state_change < current_timestamp - INTERVAL '5' MINUTE;
...
What is the opposite of :hover (on mouse leave)?
...fiddle.net/spacebeers/sELKu/3/
The definition of hover is:
The :hover selector is used to select elements when you mouse over
them.
By that definition the opposite of hover is any point at which the mouse is not over it. Someone far smarter than me has done this article, setting different t...
How do I force Postgres to use a particular index?
...d, client_id, date, and description. You want to run the following query:
SELECT client_id, SUM(amount)
FROM transactions
WHERE date >= 'yesterday'::timestamp AND date < 'today'::timestamp AND
description = 'Refund'
GROUP BY client_id
PostgreSQL may choose to use the index transaction...
When to use Hadoop, HBase, Hive and Pig?
...
Consider that you work with RDBMS and have to select what to use - full table scans, or index access - but only one of them.
If you select full table scan - use hive. If index access - HBase.
s...
Aggregate / summarize multiple variables per group (e.g. sum, mean)
...-date), sum)
# summarising a specific set of non-grouping variables using select_helpers
# see ?select_helpers for more options
df2 <- df1 %>% group_by(year, month) %>% summarise_at(vars(starts_with('x')), sum)
df2 <- df1 %>% group_by(year, month) %>% summarise_at(vars(matches('.*...
Enable 'xp_cmdshell' SQL Server
...gure calls:
declare @prevAdvancedOptions int
declare @prevXpCmdshell int
select @prevAdvancedOptions = cast(value_in_use as int) from sys.configurations where name = 'show advanced options'
select @prevXpCmdshell = cast(value_in_use as int) from sys.configurations where name = 'xp_cmdshell'
if (@...
Changing the resolution of a VNC session in linux [closed]
... a solution using TigerVNC which is the default these days.
xrandr allows selecting the display modes (a.k.a resolutions) however
due to modelines being hard
coded
any additional modeline such as "2560x1600" or "1600x900" would need to
be added into the
code. I
think the developers who wrote the co...
How can I create a unique constraint on my column (SQL Server 2008 R2)?
...the "General" tab.
Make sure you have the column you want to make unique selected in the "columns" box.
Change the "Type" box to "Unique Key".
Click "Close".
You see a little asterisk in the file window, this means changes are not yet saved.
Press Save or hit Ctrl+s. It should save, and your colu...
Facebook database design?
...O_INCREMENT=2 DEFAULT CHARSET=utf8;
Friends of Friends Query:
(
select friend_id
from friends
where user_id = 1
) union (
select distinct ff.friend_id
from
friends f
join friends ff on ff.user_id = f.friend_id
where f.use...
Eclipse debugger always blocks on ThreadPoolExecutor without any obvious exception, why?
...Debugging perspective
Go to its properties
Go to Filtering
In "Restrict to Selected Location(s)", click "Add Class"
Add java.util.concurrent.ThreadPoolExecutor
Untick the checkbox, meaning these will be ignored
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