fix the comments of the class MetaCache in the MetaCache.java

[zhangm365]

The correct comment is:
The refreshAfterWriteSec is only used for namesCache, not for metaObjCache.

Proposed changes

The source code is:

CacheFactory namesCacheFactory = new CacheFactory(
    expireAfterWriteSec,
    refreshAfterWriteSec,
    1, // names cache has one and only one entry
    true,
    null);
CacheFactory objCacheFactory = new CacheFactory(
    expireAfterWriteSec,
    OptionalLong.empty(),
    maxSize,
    true,
    null);
        
// buildCache.
namesCache = namesCacheFactory.buildCache(namesCacheLoader, null, executor);
metaObjCache = objCacheFactory.buildCache(metaObjCacheLoader, removalListener, executor);

I have debugged the source code and the debugging information is:

[doris-robot]

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[zhangm365]

run buildall

[doris-robot]

TPC-H: Total hot run time: 38017 ms

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/tpch-tools
Tpch sf100 test result on commit b31f4fe1448304cf70dc1790e052c67fe3f262af, data reload: false

------ Round 1 ----------------------------------
q1	17675	4390	4331	4331
q2	2020	194	183	183
q3	11739	991	1060	991
q4	10509	768	739	739
q5	7758	2849	2815	2815
q6	225	141	137	137
q7	960	606	611	606
q8	9344	2052	2070	2052
q9	6949	6538	6559	6538
q10	7013	2251	2254	2251
q11	456	247	241	241
q12	398	228	241	228
q13	18221	3088	3056	3056
q14	281	240	237	237
q15	541	494	466	466
q16	579	505	490	490
q17	984	692	753	692
q18	7352	6865	6765	6765
q19	1387	1045	1032	1032
q20	684	330	343	330
q21	3980	3060	2833	2833
q22	1092	1023	1004	1004
Total cold run time: 110147 ms
Total hot run time: 38017 ms

----- Round 2, with runtime_filter_mode=off -----
q1	4381	4271	4310	4271
q2	375	277	273	273
q3	2909	2672	2697	2672
q4	1941	1711	1753	1711
q5	5709	5800	5879	5800
q6	231	139	139	139
q7	2309	1838	1845	1838
q8	3303	3415	3483	3415
q9	8876	8868	8949	8868
q10	3593	3387	3356	3356
q11	624	531	530	530
q12	826	659	642	642
q13	13627	3256	3300	3256
q14	340	299	290	290
q15	544	503	493	493
q16	615	577	590	577
q17	1873	1611	1588	1588
q18	8089	7830	7826	7826
q19	1769	1631	1626	1626
q20	2225	1920	1909	1909
q21	5667	5548	5419	5419
q22	1122	1033	1021	1021
Total cold run time: 70948 ms
Total hot run time: 57520 ms

[doris-robot]

TPC-DS: Total hot run time: 192704 ms

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/tpcds-tools
TPC-DS sf100 test result on commit b31f4fe1448304cf70dc1790e052c67fe3f262af, data reload: false

query1	1248	881	904	881
query2	6459	2024	1956	1956
query3	10602	3988	3838	3838
query4	59265	23892	23321	23321
query5	5419	500	534	500
query6	413	170	178	170
query7	5840	298	298	298
query8	327	236	230	230
query9	9132	2504	2484	2484
query10	508	290	256	256
query11	18067	15127	15327	15127
query12	155	110	110	110
query13	1590	413	409	409
query14	11332	6850	7814	6850
query15	250	180	186	180
query16	7566	467	477	467
query17	1186	571	586	571
query18	2061	319	298	298
query19	317	143	142	142
query20	122	113	111	111
query21	212	108	107	107
query22	4707	4606	4688	4606
query23	34154	33380	33379	33379
query24	5935	2918	2777	2777
query25	528	386	396	386
query26	677	154	157	154
query27	1781	276	276	276
query28	3842	2077	2050	2050
query29	692	410	404	404
query30	240	150	148	148
query31	892	771	739	739
query32	83	53	50	50
query33	453	279	291	279
query34	886	505	496	496
query35	857	737	718	718
query36	1073	919	891	891
query37	146	98	87	87
query38	4029	3952	3911	3911
query39	1437	1396	1381	1381
query40	198	116	111	111
query41	49	47	45	45
query42	118	94	97	94
query43	512	472	473	472
query44	1108	747	750	747
query45	193	167	163	163
query46	1092	743	795	743
query47	1906	1772	1793	1772
query48	375	295	299	295
query49	749	463	439	439
query50	849	421	419	419
query51	7056	6814	6868	6814
query52	104	90	93	90
query53	252	177	183	177
query54	587	480	472	472
query55	75	73	79	73
query56	290	251	260	251
query57	1186	1080	1097	1080
query58	222	264	266	264
query59	3001	2805	2670	2670
query60	292	261	267	261
query61	98	128	98	98
query62	751	658	629	629
query63	223	187	189	187
query64	2825	691	653	653
query65	3216	3141	3208	3141
query66	639	338	338	338
query67	15363	15220	15268	15220
query68	2963	594	598	594
query69	410	290	285	285
query70	1160	1175	1132	1132
query71	341	274	286	274
query72	5296	3737	3982	3737
query73	761	328	329	328
query74	9113	8969	8962	8962
query75	3318	2661	2708	2661
query76	1399	976	945	945
query77	537	320	325	320
query78	9794	9936	9339	9339
query79	1042	532	532	532
query80	674	499	522	499
query81	521	235	234	234
query82	245	150	152	150
query83	179	151	152	151
query84	265	78	82	78
query85	684	287	280	280
query86	307	274	292	274
query87	4468	4270	4242	4242
query88	3099	2406	2411	2406
query89	383	296	294	294
query90	2053	203	199	199
query91	137	113	178	113
query92	58	49	50	49
query93	1055	547	538	538
query94	723	290	297	290
query95	333	259	256	256
query96	604	278	280	278
query97	3217	3081	3044	3044
query98	212	214	200	200
query99	1542	1264	1283	1264
Total cold run time: 304705 ms
Total hot run time: 192704 ms

[doris-robot]

ClickBench: Total hot run time: 31.97 s

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/clickbench-tools
ClickBench test result on commit b31f4fe1448304cf70dc1790e052c67fe3f262af, data reload: false

query1	0.05	0.04	0.04
query2	0.08	0.04	0.04
query3	0.22	0.05	0.04
query4	1.68	0.09	0.07
query5	0.51	0.50	0.48
query6	1.14	0.73	0.72
query7	0.02	0.01	0.01
query8	0.05	0.05	0.04
query9	0.54	0.50	0.48
query10	0.54	0.56	0.55
query11	0.16	0.12	0.11
query12	0.15	0.13	0.13
query13	0.60	0.59	0.59
query14	2.06	2.09	2.10
query15	0.83	0.82	0.82
query16	0.38	0.38	0.38
query17	1.07	1.04	1.06
query18	0.22	0.20	0.21
query19	1.94	1.82	1.83
query20	0.01	0.01	0.01
query21	15.39	0.65	0.65
query22	4.28	7.25	1.76
query23	18.27	1.36	1.21
query24	2.13	0.22	0.21
query25	0.16	0.08	0.08
query26	0.27	0.18	0.17
query27	0.08	0.08	0.07
query28	13.23	1.02	1.01
query29	12.60	3.35	3.31
query30	0.24	0.06	0.06
query31	2.86	0.40	0.39
query32	3.26	0.48	0.48
query33	2.97	3.00	3.03
query34	17.02	4.37	4.43
query35	4.49	4.46	4.46
query36	0.65	0.49	0.50
query37	0.19	0.15	0.15
query38	0.15	0.14	0.14
query39	0.05	0.04	0.04
query40	0.15	0.12	0.12
query41	0.10	0.05	0.05
query42	0.05	0.05	0.06
query43	0.04	0.04	0.04
Total cold run time: 110.88 s
Total hot run time: 31.97 s