"Zbyt wiele zmiennych SQL" Błąd w Django witih sqlite3

Question

dostaję ten błąd przy użyciu sqlite3 w Django:

Exception Value: too many SQL variables 

i myślę, że odpowiedź na to jest to, z http://www.sqlite.org/limits.html:

Many SQL programmers are familiar with using a question mark ("?") as a host parameter. SQLite also supports named host parameters prefaced by ":", "$", or "@" and numbered host parameters of the form "?123".

To prevent excessive memory allocations, the maximum value of a host parameter number is SQLITE_MAX_VARIABLE_NUMBER, which defaults to 999."

Jednak istnieje nieparzystość, której nie rozumiem. To samo dotyczy tego samego zapytania z sesji powłoki Django (uruchamianej z python manage.py shell), ale nie w przypadku wywołania z mojego views.py.

Są to linie kodu, które powodują, że błąd:

vals = Company.objects.filter(id__in=comp_ids).values('id', 'name').order_by('name') 
names_map = SortedDict(vals) 

gdzie comp_ids jest zestaw zawierający 1038 elementy całkowite.

Dokładne to samo zapytanie, z jeszcze większym nie. z comp_ids (3800+) działa dobrze w powłoka django (uruchomiona z python manage.py shell) - słownik otrzymuje utworzony i mógłbym iterować przez niego.

Próbowałem rozbić comp_ids na zestawy np. [:996] (który wydawał się być limitem , zanim został zablokowany), tj. filter(id__in=comp_ids[:996]), następnie reszta w następnej iteracji, która byłaby zgodna z wyjaśnieniem "nr parametrów hosta" .

Ale dlaczego miałoby działać w powłoce django, ale nie od views.py?

EDIT: Niektórzy więcej informacji: wpisaniu zapytania do sqlite powłoki (manage.py dbshell) zwraca pełną zestaw wyników bez błędów, tak samo jak w powłoce django (manage.py shell).

Oto dokładna lista parametrów (1039 elementów) oraz zapytania, gdybyś chciał znać szczegóły:

params

 
(2, 3, 4, 2053, 6, 7, 2732, 10, 3737, 13, 2063, 2064, 17, 18, 21, 2393, 2052, 29, 30, 32, 2456, 35, 36, 38, 40, 2396, 42, 2731, 45, 46, 2095, 3343, 49, 2098, 2252, 53, 54, 58, 59, 2058, 62, 63, 64, 66, 67, 72, 2123, 3426, 3344, 79, 80, 81, 85, 2134, 87, 91, 92, 95, 98, 2747, 2149, 102, 104, 106, 2155, 109, 110, 3773, 2455, 2165, 118, 122, 2171, 2172, 127, 134, 135, 137, 138, 2187, 2413, 145, 148, 2414, 2198, 2199, 152, 153, 154, 2204, 157, 2210, 163, 2417, 169, 170, 2219, 172, 173, 3279, 2077, 179, 180, 181, 2230, 2231, 184, 186, 187, 2237, 190, 191, 2240, 2241, 3787, 2245, 2246, 2247, 2248, 2249, 2251, 204, 205, 207, 208, 209, 210, 213, 214, 2263, 2265, 3450, 222, 2273, 2274, 2275, 228, 2277, 2811, 231, 234, 2283, 2284, 238, 240, 243, 248, 250, 2299, 2300, 254, 2303, 2305, 258, 2307, 2308, 2309, 2310, 2311, 2312, 2313, 267, 269, 2318, 271, 2320, 2321, 2322, 2323, 2325, 278, 2327, 280, 282, 283, 285, 286, 287, 290, 2342, 295, 298, 2347, 2348, 2349, 2350, 2351, 304, 2353, 307, 309, 312, 318, 320, 321, 323, 326, 327, 328, 332, 333, 334, 2385, 338, 2387, 2388, 2389, 2390, 2391, 2392, 345, 2394, 347, 348, 350, 352, 354, 355, 356, 357, 359, 360, 2410, 364, 365, 366, 2415, 2416, 369, 2451, 373, 2422, 375, 377, 2426, 2428, 2429, 2430, 2432, 2433, 387, 2454, 391, 2441, 2443, 398, 399, 400, 401, 2553, 403, 404, 405, 406, 407, 408, 409, 410, 411, 413, 2462, 3628, 418, 2459, 420, 2469, 2470, 2472, 425, 427, 2476, 2461, 2483, 2485, 440, 441, 2490, 443, 444, 445, 446, 2496, 2497, 2499, 2501, 2502, 455, 2504, 2505, 459, 460, 2466, 2510, 463, 465, 466, 467, 469, 470, 2519, 2520, 2468, 474, 2529, 2531, 484, 486, 487, 488, 490, 491, 493, 2542, 2543, 2544, 497, 498, 499, 500, 2549, 502, 2551, 504, 505, 2554, 2555, 2556, 509, 2558, 511, 2560, 2562, 2475, 2564, 517, 2566, 2567, 2568, 2569, 523, 2572, 526, 527, 529, 536, 538, 539, 2588, 2589, 2590, 2596, 550, 552, 556, 2605, 2607, 2608, 2612, 565, 566, 567, 568, 580, 2634, 587, 2636, 2638, 2639, 2270, 595, 598, 2489, 605, 606, 609, 610, 2407, 615, 618, 619, 620, 2669, 2670, 2493, 2672, 2152, 628, 629, 630, 2680, 2682, 2684, 640, 641, 642, 2691, 645, 648, 650, 2699, 2700, 2701, 2702, 2703, 2705, 659, 2708, 661, 2712, 667, 2718, 2719, 2720, 2721, 2723, 2724, 2725, 2728, 681, 2730, 2614, 684, 2733, 2735, 2736, 689, 2739, 2741, 2746, 699, 701, 706, 707, 2757, 2759, 2760, 2508, 2763, 2766, 721, 2771, 725, 730, 2511, 732, 2170, 734, 2343, 743, 749, 2798, 2799, 752, 753, 2515, 756, 2078, 2807, 2808, 2412, 763, 2813, 766, 769, 2818, 2821, 2822, 779, 2861, 2833, 2834, 2835, 2836, 2837, 790, 802, 2852, 2854, 2856, 2550, 810, 2860, 813, 2862, 2863, 817, 2869, 2870, 2871, 824, 826, 2876, 829, 830, 2882, 836, 2885, 2886, 3574, 2890, 2892, 2893, 847, 2896, 2872, 2899, 2902, 2546, 2909, 2256, 2912, 2913, 870, 2920, 2921, 2922, 876, 2930, 887, 2937, 3903, 892, 893, 894, 895, 896, 897, 898, 899, 900, 901, 903, 904, 905, 906, 907, 908, 909, 910, 911, 2884, 2970, 927, 2977, 2978, 2979, 2980, 2981, 2545, 941, 942, 2205, 948, 949, 950, 951, 952, 953, 954, 955, 956, 957, 958, 959, 960, 961, 962, 963, 964, 965, 3014, 967, 968, 969, 970, 971, 3234, 2552, 980, 981, 982, 983, 985, 2895, 3038, 995, 996, 998, 2897, 2538, 2761, 3051, 1012, 1013, 3062, 3063, 3066, 2559, 3073, 1027, 1028, 1029, 1030, 2421, 3080, 1036, 1038, 1039, 1040, 1041, 3092, 3246, 3853, 1050, 3099, 1057, 3109, 3112, 1067, 1068, 1073, 1074, 1075, 1076, 1078, 1081, 2491, 1086, 2229, 1088, 1089, 1090, 1091, 1092, 1093, 1095, 1096, 1097, 1098, 1099, 1100, 1101, 1102, 1103, 1104, 1105, 1106, 1107, 1108, 1109, 1110, 1111, 1112, 3161, 1119, 3170, 2235, 3174, 3176, 3177, 1132, 1133, 1134, 1135, 1136, 3186, 1141, 3192, 3193, 3194, 3195, 3197, 3198, 2425, 1152, 1155, 1156, 3205, 2924, 3214, 1168, 1169, 1171, 1172, 1173, 1174, 1175, 1176, 3225, 1178, 3230, 1186, 1189, 1193, 1194, 1195, 1196, 3245, 1198, 1199, 1200, 1202, 2541, 3273, 1210, 3259, 1213, 1225, 1226, 1228, 1230, 2253, 3280, 3281, 1234, 1235, 1238, 1243, 1244, 1248, 1249, 3298, 3299, 1253, 3302, 2257, 3304, 3305, 3306, 3308, 1262, 2838, 3315, 3317, 3381, 1277, 1278, 3327, 3331, 3332, 1285, 2945, 1288, 1289, 1292, 1295, 1296, 1298, 3347, 3348, 3349, 1302, 3351, 3352, 3353, 1306, 1307, 3356, 1312, 3364, 1320, 3370, 3371, 3372, 3374, 3375, 1328, 3377, 3378, 3380, 1333, 1334, 3388, 3390, 3296, 3394, 3395, 2227, 1350, 2615, 1357, 1361, 1362, 3411, 3412, 3413, 1368, 2276, 1371, 1372, 3105, 1378, 2228, 3428, 3430, 3433, 1400, 1402, 1404, 3453, 3455, 3808, 1409, 3458, 3459, 1412, 1414, 1416, 1417, 1418, 1419, 1420, 2093, 3470, 1437, 3486, 1439, 2571, 3491, 3492, 3493, 1446, 2435, 1454, 1463, 3663, 3523, 1477, 1478, 1479, 1480, 1481, 1482, 3531, 1484, 1488, 1489, 1490, 3540, 1494, 1495, 1496, 3546, 3547, 2298, 1510, 1512, 3666, 1520, 1523, 2302, 1526, 1527, 3584, 1539, 1540, 1542, 1543, 1548, 1549, 3393, 1554, 1555, 1560, 1561, 3079, 1565, 2507, 3616, 3617, 1570, 3619, 3620, 3621, 3622, 1575, 3624, 2817, 3629, 3630, 1583, 1590, 1591, 1592, 2996, 3643, 3645, 2997, 3649, 2781, 3653, 3655, 1608, 3657, 2317, 1618, 3667, 1620, 3669, 1625, 2319, 3002, 2782, 1633, 1634, 3199, 3691, 3346, 3688, 1650, 1656, 3007, 3709, 3008, 1666, 2616, 3009, 2668, 2306, 3723, 3010, 2238, 1681, 1682, 1683, 1687, 3012, 3738, 2671, 1693, 3013, 1697, 1698, 2548, 3749, 3755, 3757, 3758, 2333, 1714, 1718, 3770, 3018, 1729, 3778, 3783, 1739, 1744, 3793, 1746, 1752, 1753, 1755, 3741, 3707, 1771, 1774, 2514, 1779, 2494, 3831, 1788, 2346, 3029, 3840, 3182, 2689, 1802, 1803, 2690, 1811, 1815, 1817, 3011, 2352, 1827, 2467, 1832, 3881, 1839, 1840, 2107, 1848, 1849, 2698, 2653, 1855, 1857, 1864, 1867, 1872, 1873, 3923, 1878, 1882, 1889, 3354, 1903, 1904, 2366, 1915, 1920, 1921, 1927, 1928, 1930, 1931, 3133, 1943, 1947, 1957, 1958, 1959, 1964, 1967, 1968, 1976, 2809, 3612, 1987, 1988, 1989, 3745, 1994, 2000, 2003, 2382, 2008, 3613, 2021, 2022, 3410, 3464, 2033, 2034, 2037, 2038, 2729, 2044) 

zapytań

 
'SELECT "screen_company"."id", "screen_company"."name" FROM "screen_company" WHERE "screen_company"."id" IN (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) ORDER BY "screen_company"."name" ASC' 

(Nawiasem mówiąc, nie musisz używać pdb do tego - django bardzo pomocnie wyświetla ślad w przeglądarce (w render_to_response()?), Gdy wystąpi błąd, z pełną listę zmiennych lokalnych na każdym kroku, dzięki czemu można zobaczyć pełną kwerendę tam.)

miałem jednak wcześniej próbował wkraczającego w kodzie Django z WPB i znaleziono błąd został faktycznie pochodzący z pysqlite2.dbapi2 Pythona (lub sqlite3.dbapi2) modułu, na linii 200 z django/db/backendy/sqlite3/base.py:

return Database.Cursor.execute(self, query, params) 

(który był również w pomocne śledzenie pokazane na stronie błędu), gdzie Baza danych jest aliasem dla pysqlite2.dbapi2 lub sqlite3.dbapi2, w zależności od wersji w swojej wersji python.

Ale myślałem, że był zbyt daleko w dół stosu wywołań zachować debugowanie (na razie), więc postanowiliśmy zatrzymać się i zaczął myśleć o obejściach i googlowania dla zamiast odpowiedzi. :)

Answer 1

Nie ma sposobu, aby ominąć to, jest to ograniczenie SQLITE. Twoje zapytanie będzie jednak działało poprawnie na MySQL. Ale jeśli musisz zrobić tego rodzaju zapytanie, najprawdopodobniej zrobisz to źle. Twój schemat mysql powinien zostać przerobiony. A jeśli nie możesz, możesz podzielić to zapytanie na 100 małych zapytań.

Answer 2

Uwaga: Nie jestem Django Problem ekspert

jest to, że w zapytaniu

vals = Company.objects.filter(id__in=comp_ids)... 

zdać nadęty zbiór wartości i pod nią silnik nie może wykonać zapytania. Na szczęście sqlalchemy, które wykonujesz w tym wierszu, jest lazy. Wykonujesz SELECT, a następnie filtrujesz wpisy "ręcznie" bez dużych kar za wydajność.

będzie to wyglądać mniej więcej, tak:

# here you should do a proper session.query(CompanyTable) 
vals_all = Company.objects 

vals_filtered = (item for item in vals_all if item.id in comp_ids) 
vals_ordered = sorted(vals_filtered, key=attrgetter('name')) 
vals_final = [(v.id, v.name) for v in vals_ordered] 

Answer 3

Googling ten komunikat o błędzie przyniósł mi tu więc dodanie moje rozwiązanie.

W moim przypadku ten błąd był spowodowany line:

Event.objects.all().delete() 

Prawdopodobnie Django próbował "DELETE WHERE id IN (,,, ...??" I lista identyfikatorów było długo .

występ nie był to problem dla mnie, więc rozwiązać ten przez:

while Event.objects.count(): 
    ids = Event.objects.values_list('pk', flat=True)[:100] 
    Event.objects.filter(pk__in = ids).delete() 

Answer 4

I Hava znaleźć ten sam błąd po uruchomieniu linii:

Entry.objects.all().delete() 

I rozwiązać problem przez

while Entry.objects.count(): 
      Entry.objects.all()[0].delete() 

myślę, że to lepszy pomysł niż inni.

Answer 5

faktycznie te limity są podane tutaj: https://www.sqlite.org/c3ref/c_limit_attached.html#sqlitelimitvariablenumber

z wyjaśnieniem:

Maximum Number Of Host Parameters In A Single SQL Statement

A host parameter is a place-holder in an SQL statement that is filled in using one of the sqlite3_bind_XXXX() interfaces. Many SQL programmers are familiar with using a question mark ("?") as a host parameter. SQLite also supports named host parameters prefaced by ":", "$", or "@" and numbered host parameters of the form "?123".

Each host parameter in an SQLite statement is assigned a number. The numbers normally begin with 1 and increase by one with each new parameter. However, when the "?123" form is used, the host parameter number is the number that follows the question mark.

SQLite allocates space to hold all host parameters between 1 and the largest host parameter number used. Hence, an SQL statement that contains a host parameter like ?1000000000 would require gigabytes of storage. This could easily overwhelm the resources of the host machine. To prevent excessive memory allocations, the maximum value of a host parameter number is SQLITE_MAX_VARIABLE_NUMBER, which defaults to 999.

The maximum host parameter number can be lowered at run-time using the sqlite3_limit(db,SQLITE_LIMIT_VARIABLE_NUMBER,size) interface.

https://www.sqlite.org/limits.html