221
221
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
222
222
show status like 'Last_query_cost';
223
223
Variable_name Value
224
Last_query_cost 817.599000
225
225
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
226
226
id select_type table type possible_keys key key_len ref rows Extra
227
1 # t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
228
1 # t2 ALL NULL NULL NULL NULL 6
229
1 # t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
230
1 # t4 ALL NULL NULL NULL NULL 12 Using join buffer
231
1 # t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
232
1 # t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer
233
1 # t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
227
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
228
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using join buffer
229
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
230
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
231
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
232
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer
233
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
234
234
show status like 'Last_query_cost';
235
235
Variable_name Value
236
Last_query_cost 286.199000
237
237
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
238
238
id select_type table type possible_keys key key_len ref rows Extra
239
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
240
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using join buffer
239
241
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
240
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
241
242
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
242
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using join buffer
243
243
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
244
244
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer
245
245
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
246
246
show status like 'Last_query_cost';
247
247
Variable_name Value
248
Last_query_cost 286.199000
249
249
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
250
250
id select_type table type possible_keys key key_len ref rows Extra
251
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
252
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer
251
253
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
252
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
253
254
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
254
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer
255
255
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
256
256
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer
257
257
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
258
258
show status like 'Last_query_cost';
259
259
Variable_name Value
260
Last_query_cost 286.199000
261
261
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
262
262
id select_type table type possible_keys key key_len ref rows Extra
263
263
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
297
297
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
298
298
show status like 'Last_query_cost';
299
299
Variable_name Value
300
Last_query_cost 817.599000
301
301
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
302
302
id select_type table type possible_keys key key_len ref rows Extra
303
303
1 SIMPLE t1 ALL PRIMARY NULL NULL NULL 3
304
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
305
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
306
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
304
307
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join buffer
305
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
306
308
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer
307
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
308
309
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer
309
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
310
310
show status like 'Last_query_cost';
311
311
Variable_name Value
312
Last_query_cost 790.599000
313
313
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
314
314
id select_type table type possible_keys key key_len ref rows Extra
315
315
1 SIMPLE t1 ALL PRIMARY NULL NULL NULL 3
321
321
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer
322
322
show status like 'Last_query_cost';
323
323
Variable_name Value
324
Last_query_cost 790.599000
325
325
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
326
326
id select_type table type possible_keys key key_len ref rows Extra
327
327
1 SIMPLE t1 ALL PRIMARY NULL NULL NULL 3
328
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1
329
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
330
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
328
331
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join buffer
329
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1
330
332
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer
331
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
332
333
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer
333
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
334
334
show status like 'Last_query_cost';
335
335
Variable_name Value
336
Last_query_cost 790.599000
337
337
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
338
338
id select_type table type possible_keys key key_len ref rows Extra
339
339
1 SIMPLE t1 ALL PRIMARY NULL NULL NULL 3
373
373
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
374
374
show status like 'Last_query_cost';
375
375
Variable_name Value
376
Last_query_cost 817.599000
377
377
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
378
378
id select_type table type possible_keys key key_len ref rows Extra
379
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
380
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using join buffer
379
381
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
380
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
381
382
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
382
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using join buffer
383
383
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
384
384
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer
385
385
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
386
386
show status like 'Last_query_cost';
387
387
Variable_name Value
388
Last_query_cost 286.199000
389
389
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
390
390
id select_type table type possible_keys key key_len ref rows Extra
391
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
392
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using join buffer
391
393
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
392
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
393
394
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
394
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using join buffer
395
395
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
396
396
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer
397
397
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
398
398
show status like 'Last_query_cost';
399
399
Variable_name Value
400
Last_query_cost 286.199000
401
401
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
402
402
id select_type table type possible_keys key key_len ref rows Extra
403
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
404
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer
403
405
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
404
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
405
406
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
406
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer
407
407
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
408
408
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer
409
409
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
410
410
show status like 'Last_query_cost';
411
411
Variable_name Value
412
Last_query_cost 286.199000
413
413
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
414
414
id select_type table type possible_keys key key_len ref rows Extra
415
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
416
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer
415
417
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
416
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
417
418
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
418
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer
419
419
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
420
420
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer
421
421
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
422
422
show status like 'Last_query_cost';
423
423
Variable_name Value
424
Last_query_cost 286.199000
425
425
set optimizer_prune_level=1;
426
426
select @@optimizer_prune_level;
427
427
@@optimizer_prune_level