Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>I've arrived rather late to this party, but I don't see my favorite trick listed in the answers.</p> <p>Under *NIX, an <code>alarm(2)</code> is inherited across an <code>execve(2)</code> and SIGALRM is fatal by default. So, you can often simply:</p> <pre><code>$ doalarm () { perl -e 'alarm shift; exec @ARGV' "$@"; } # define a helper function $ doalarm 300 ./foo.sh args </code></pre> <p>or install a <a href="http://www.pilcrow.madison.wi.us/" rel="noreferrer">trivial C wrapper</a> to do that for you.</p> <p><strong>Advantages</strong> Only one PID is involved, and the mechanism is simple. You won't kill the wrong process if, for example, <code>./foo.sh</code> exited "too quickly" and its PID was re-used. You don't need several shell subprocesses working in concert, which can be done correctly but is rather race-prone.</p> <p><strong>Disadvantages</strong> The time-constrained process cannot manipulate its alarm clock (e.g., <code>alarm(2)</code>, <code>ualarm(2)</code>, <code>setitimer(2)</code>), since this would likely clear the inherited alarm. Obviously, neither can it block or ignore SIGALRM, though the same can be said of SIGINT, SIGTERM, etc. for some other approaches.</p> <p>Some (very old, I think) systems implement <code>sleep(2)</code> in terms of <code>alarm(2)</code>, and, even today, some programmers use <code>alarm(2)</code> as a crude internal timeout mechanism for I/O and other operations. In my experience, however, this technique is applicable to the vast majority of processes you want to time limit.</p>
    singulars
    1. This table or related slice is empty.
    1. POCommand line command to auto-kill a command after a certain amount of time
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USCommunity
    1. USpilcrow
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POCommand line command to auto-kill a command after a certain amount of time
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COI tried this and it works beautifully. This may be my new favorite.
      singulars
      1. PO
      1. USdreeves
    2. COI have been using the perl script one liner. I have encountered an odd difficulty: it does not seem to work when the command is a bash function. `doalarm 7200 echo "Cool"` works perfectly, `testfun () { echo $1 } ; testfun "Cool"` works perfectly, but `doalarm 7200 testfun "Cool"` does not work. Thanks for any suggestions.
      singulars
      1. PO
      1. USEtienne Low-Décarie
    3. CO@EtienneLow-Décarie, yes, the this style of wrapper will only work on commands that are exec()d as separate processes. So, shell functions and builtins won't be doalarm-able.
      singulars
      1. PO
      1. USpilcrow
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload