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modes_kml: fix case where KML generation thread dies

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SQLite does not deal well with concurrency.  Avoid database locked
errors by synchronizing database access using a threading.Lock().
This commit is contained in:
Johnathan Corgan
2012-10-06 08:44:33 -07:00
parent d88d21f672
commit c0d24f12c9
2 changed files with 19 additions and 12 deletions
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8
python/modes_kml.py
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@@ -93,14 +93,14 @@ class modes_kml(threading.Thread, modes_output_sql):
#read the database and add KML
q = "select distinct icao from positions where seen > datetime('now', '-5 minute')"
c = self._db.cursor()
c.execute(q)
self.locked_execute(c, q)
icaolist = c.fetchall()
#now we have a list icaolist of all ICAOs seen in the last 5 minutes
for icao in icaolist:
#print "ICAO: %x" % icao
q = "select * from positions where icao=%i and seen > datetime('now', '-2 hour') ORDER BY seen DESC" % icao
c.execute(q)
self.locked_execute(c, q)
track = c.fetchall()
#print "Track length: %i" % len(track)
if len(track) != 0:
@@ -128,7 +128,7 @@ class modes_kml(threading.Thread, modes_output_sql):
#now get metadata
q = "select ident from ident where icao=%i" % icao
c.execute(q)
self.locked_execute(c, q)
r = c.fetchall()
if len(r) != 0:
ident = r[0][0]
@@ -136,7 +136,7 @@ class modes_kml(threading.Thread, modes_output_sql):
#if ident is None: ident = ""
#get most recent speed/heading/vertical
q = "select seen, speed, heading, vertical from vectors where icao=%i order by seen desc limit 1" % icao
c.execute(q)
self.locked_execute(c, q)
r = c.fetchall()
if len(r) != 0:
seen = r[0][0]