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Micro-optimizations when reading from the db

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Kovid Goyal 2013-07-22 13:17:10 +05:30
parent d336d75a81
commit e105493d78
1 changed files with 24 additions and 15 deletions
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35
src/calibre/db/tables.py
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@ -53,12 +53,10 @@ class Table(object):
self.sort_alpha = metadata.get('is_multiple', False) and metadata.get('display', {}).get('sort_alpha', False) self.sort_alpha = metadata.get('is_multiple', False) and metadata.get('display', {}).get('sort_alpha', False)
# self.unserialize() maps values from the db to python objects # self.unserialize() maps values from the db to python objects
self.unserialize = \ self.unserialize = {
{
'datetime': _c_convert_timestamp, 'datetime': _c_convert_timestamp,
'bool': bool 'bool': bool
}.get( }.get(metadata['datatype'], None)
metadata['datatype'], lambda x: x)
if name == 'authors': if name == 'authors':
# Legacy # Legacy
self.unserialize = lambda x: x.replace('|', ',') if x else None self.unserialize = lambda x: x.replace('|', ',') if x else None
@ -93,9 +91,13 @@ class OneToOneTable(Table):
def read(self, db): def read(self, db):
self.book_col_map = {} self.book_col_map = {}
idcol = 'id' if self.metadata['table'] == 'books' else 'book' idcol = 'id' if self.metadata['table'] == 'books' else 'book'
for row in db.conn.execute('SELECT {0}, {1} FROM {2}'.format(idcol, query = db.conn.execute('SELECT {0}, {1} FROM {2}'.format(idcol,
self.metadata['column'], self.metadata['table'])): self.metadata['column'], self.metadata['table']))
self.book_col_map[row[0]] = self.unserialize(row[1]) if self.unserialize is None:
self.book_col_map = {row[0]:row[1] for row in query}
else:
us = self.unserialize
self.book_col_map = {row[0]:us(row[1]) for row in query}
def remove_books(self, book_ids, db): def remove_books(self, book_ids, db):
clean = set() clean = set()
@ -119,7 +121,7 @@ class SizeTable(OneToOneTable):
for row in db.conn.execute( for row in db.conn.execute(
'SELECT books.id, (SELECT MAX(uncompressed_size) FROM data ' 'SELECT books.id, (SELECT MAX(uncompressed_size) FROM data '
'WHERE data.book=books.id) FROM books'): 'WHERE data.book=books.id) FROM books'):
self.book_col_map[row[0]] = self.unserialize(row[1]) self.book_col_map[row[0]] = row[1]
def update_sizes(self, size_map): def update_sizes(self, size_map):
self.book_col_map.update(size_map) self.book_col_map.update(size_map)
@ -180,9 +182,13 @@ class ManyToOneTable(Table):
self.read_maps(db) self.read_maps(db)
def read_id_maps(self, db): def read_id_maps(self, db):
for row in db.conn.execute('SELECT id, {0} FROM {1}'.format( query = db.conn.execute('SELECT id, {0} FROM {1}'.format(
self.metadata['column'], self.metadata['table'])): self.metadata['column'], self.metadata['table']))
self.id_map[row[0]] = self.unserialize(row[1]) if self.unserialize is None:
self.id_map = {row[0]:row[1] for row in query}
else:
us = self.unserialize
self.id_map = {row[0]:us(row[1]) for row in query}
def read_maps(self, db): def read_maps(self, db):
for row in db.conn.execute( for row in db.conn.execute(
@ -348,11 +354,14 @@ class AuthorsTable(ManyToManyTable):
def read_id_maps(self, db): def read_id_maps(self, db):
self.alink_map = {} self.alink_map = {}
self.asort_map = {} self.asort_map = {}
self.id_map = {}
us = self.unserialize
for row in db.conn.execute( for row in db.conn.execute(
'SELECT id, name, sort, link FROM authors'): 'SELECT id, name, sort, link FROM authors'):
self.id_map[row[0]] = self.unserialize(row[1]) val = us(row[1])
self.id_map[row[0]] = self.unserialize(val)
self.asort_map[row[0]] = (row[2] if row[2] else self.asort_map[row[0]] = (row[2] if row[2] else
author_to_author_sort(row[1])) author_to_author_sort(val))
self.alink_map[row[0]] = row[3] self.alink_map[row[0]] = row[3]
def set_sort_names(self, aus_map, db): def set_sort_names(self, aus_map, db):