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Use delayed commit for bulk operations.

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Delay compaction commit after range deletion.
Delay commit after search results deletion.
This commit is contained in:
Arun Prakash Jana 2016-10-29 00:01:52 +05:30
parent 1bc4ed2564
commit 96676a35bf
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GPG Key ID: A75979F35C080412
1 changed files with 32 additions and 12 deletions
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buku
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@ -745,11 +745,12 @@ class BukuDb:
return results
def compactdb(self, index):
def compactdb(self, index, delay_commit=False):
'''When an entry at index is deleted, move the last
entry in DB to index, if index is lesser.
Params: index of deleted entry
:param index: DB index of deleted entry
:param delay_commit: do not commit to DB, caller's responsibility
'''
self.cur.execute('SELECT MAX(id) from bookmarks')
@ -772,26 +773,39 @@ class BukuDb:
self.cur.execute(query2, (row[0],))
self.cur.execute(query3,
(index, row[1], row[2], row[3], row[4],))
self.conn.commit()
if not delay_commit:
self.conn.commit()
print('Index %d moved to %d' % (row[0], index))
def delete_bookmark(self, index, low=0, high=0, is_range=False):
def delete_bookmark(self, index, low=0, high=0, is_range=False,
delay_commit=False):
'''Delete a single record or remove the table if index is None
Params: index to delete
:param index: DB index of deleted entry
:param low: lower index of range
:param low: higher index of range
:param is_range: a range is passed using low and high arguments
:param delay_commit: do not commit to DB, caller's responsibility
'''
if is_range:
try:
query = 'DELETE from bookmarks where id BETWEEN ? AND ?'
self.cur.execute(query, (low, high))
self.conn.commit()
if not delay_commit:
self.conn.commit()
print('Bookmarks from index %s to %s deleted' % (low, high))
# Compact DB by ascending order of index to ensure
# the existing higher indices move only once
# Delayed commit is forced
for index in range(low, high + 1):
self.compactdb(index, delay_commit=True)
if not delay_commit:
self.conn.commit()
except IndexError:
logger.error('Index out of bound')
for index in range(low, high + 1):
self.compactdb(index)
elif index == 0: # Remove the table
resp = input('Remove ALL bookmarks? (y/n): ')
if resp != 'y':
@ -804,10 +818,11 @@ class BukuDb:
try:
query = 'DELETE FROM bookmarks WHERE id = ?'
self.cur.execute(query, (index,))
self.conn.commit()
if not delay_commit:
self.conn.commit()
if self.cur.rowcount == 1:
print('Removed index %d' % index)
self.compactdb(index)
self.compactdb(index, delay_commit)
else:
logger.error('No matching index')
except IndexError:
@ -818,6 +833,8 @@ class BukuDb:
def delete_resultset(self, results):
'''Delete search results in descending order of DB index.
Indices are expected to be unique and in ascending order.
This API forces a delayed commit.
'''
resp = input('Delete the search results? (y/n): ')
@ -828,9 +845,12 @@ class BukuDb:
pos = len(results) - 1
while pos >= 0:
idx = results[pos][0]
self.delete_bookmark(idx)
self.delete_bookmark(idx, delay_commit=True)
pos -= 1
if len(results) > 0:
self.conn.commit()
def delete_all_bookmarks(self):
'''Should be called only inside delete_bookmark
Drops the bookmark table if it exists