branch-3.1 : [Fix](Variant) Fix null value handling when serializing to JSON string #55876

[eldenmoon]

cherry-pick #55876

[hello-stephen]

Thank you for your contribution to Apache Doris.
Don't know what should be done next? See How to process your PR.

Please clearly describe your PR:

1. What problem was fixed (it's best to include specific error reporting information). How it was fixed.
2. Which behaviors were modified. What was the previous behavior, what is it now, why was it modified, and what possible impacts might there be.
3. What features were added. Why was this function added?
4. Which code was refactored and why was this part of the code refactored?
5. Which functions were optimized and what is the difference before and after the optimization?

[eldenmoon]

run buildall

[eldenmoon]

run buildall

[eldenmoon]

run buildall

[doris-robot]

TPC-H: Total hot run time: 32493 ms

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/tpch-tools
Tpch sf100 test result on commit a2c05e28be9e4346647e1b46785dcbe1ce41cd64, data reload: false

------ Round 1 ----------------------------------
q1	17600	5392	5405	5392
q2	2020	406	291	291
q3	11681	1263	738	738
q4	10547	860	452	452
q5	9733	2354	2097	2097
q6	196	161	133	133
q7	899	722	623	623
q8	9322	1425	1172	1172
q9	5181	4978	4888	4888
q10	6785	2254	1873	1873
q11	465	281	268	268
q12	329	358	214	214
q13	17796	3632	3005	3005
q14	226	218	210	210
q15	535	468	452	452
q16	412	416	378	378
q17	592	865	349	349
q18	6769	6399	6246	6246
q19	1323	953	553	553
q20	324	335	207	207
q21	2904	2161	1955	1955
q22	1024	1049	997	997
Total cold run time: 106663 ms
Total hot run time: 32493 ms

----- Round 2, with runtime_filter_mode=off -----
q1	5599	5516	5483	5483
q2	232	324	238	238
q3	2221	2615	2300	2300
q4	1365	1828	1373	1373
q5	4389	5035	4944	4944
q6	173	164	137	137
q7	2066	1982	1858	1858
q8	2654	2830	2724	2724
q9	7302	7241	7318	7241
q10	3067	3251	2744	2744
q11	589	515	505	505
q12	700	778	611	611
q13	3366	3750	3114	3114
q14	304	301	268	268
q15	515	470	457	457
q16	458	492	433	433
q17	1227	1728	1256	1256
q18	7696	7389	7283	7283
q19	771	1179	1072	1072
q20	2002	2020	1851	1851
q21	5384	4930	4610	4610
q22	1068	1066	995	995
Total cold run time: 53148 ms
Total hot run time: 51497 ms

[doris-robot]

TPC-DS: Total hot run time: 192696 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 a2c05e28be9e4346647e1b46785dcbe1ce41cd64, data reload: false

query1	957	407	410	407
query2	6310	1933	1903	1903
query3	8690	198	198	198
query4	33536	23870	23745	23745
query5	3662	609	466	466
query6	298	203	184	184
query7	4203	494	317	317
query8	294	248	244	244
query9	9173	2639	2600	2600
query10	481	337	258	258
query11	18156	15459	15392	15392
query12	160	111	108	108
query13	1552	531	419	419
query14	9237	6783	6630	6630
query15	240	190	178	178
query16	7865	634	543	543
query17	1568	761	603	603
query18	2094	416	348	348
query19	206	190	171	171
query20	123	123	114	114
query21	212	131	111	111
query22	4533	4650	4432	4432
query23	35519	34133	33858	33858
query24	8527	2725	2784	2725
query25	560	507	437	437
query26	1199	293	179	179
query27	2805	477	362	362
query28	5775	2223	2207	2207
query29	813	595	462	462
query30	245	189	176	176
query31	1039	931	848	848
query32	97	57	62	57
query33	527	375	321	321
query34	742	883	527	527
query35	800	824	742	742
query36	1020	1022	956	956
query37	112	94	69	69
query38	3990	4036	3991	3991
query39	1619	1489	1476	1476
query40	206	124	106	106
query41	50	44	49	44
query42	120	107	107	107
query43	517	528	489	489
query44	1325	818	826	818
query45	184	178	175	175
query46	880	1068	687	687
query47	1992	2001	1951	1951
query48	412	425	354	354
query49	805	490	495	490
query50	689	697	446	446
query51	7368	7281	7330	7281
query52	102	107	94	94
query53	233	262	200	200
query54	556	562	474	474
query55	74	79	81	79
query56	278	258	262	258
query57	1275	1302	1222	1222
query58	246	219	224	219
query59	3092	3180	3034	3034
query60	292	288	264	264
query61	118	112	125	112
query62	838	753	709	709
query63	248	215	205	205
query64	4972	994	633	633
query65	3433	3309	3306	3306
query66	982	416	305	305
query67	15919	15901	15627	15627
query68	7482	814	536	536
query69	506	306	260	260
query70	1226	1094	1125	1094
query71	393	298	267	267
query72	5787	3781	3803	3781
query73	629	751	349	349
query74	10293	9120	9186	9120
query75	3204	3185	2688	2688
query76	3245	1175	801	801
query77	595	368	268	268
query78	10495	10455	9576	9576
query79	3479	900	588	588
query80	798	524	444	444
query81	517	256	222	222
query82	649	126	91	91
query83	175	159	147	147
query84	286	104	82	82
query85	773	367	300	300
query86	389	307	270	270
query87	4352	4380	4249	4249
query88	5469	2442	2392	2392
query89	411	329	294	294
query90	1773	192	191	191
query91	144	142	112	112
query92	66	60	53	53
query93	2762	885	535	535
query94	680	416	315	315
query95	344	281	272	272
query96	485	613	280	280
query97	3218	3246	3142	3142
query98	226	209	203	203
query99	1557	1409	1321	1321
Total cold run time: 298553 ms
Total hot run time: 192696 ms

[doris-robot]

ClickBench: Total hot run time: 28.64 s

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/clickbench-tools
ClickBench test result on commit a2c05e28be9e4346647e1b46785dcbe1ce41cd64, data reload: false

query1	0.04	0.04	0.03
query2	0.07	0.03	0.02
query3	0.23	0.07	0.06
query4	1.62	0.11	0.10
query5	0.54	0.50	0.51
query6	1.14	0.72	0.72
query7	0.03	0.02	0.01
query8	0.04	0.03	0.03
query9	0.56	0.49	0.49
query10	0.55	0.56	0.58
query11	0.15	0.11	0.11
query12	0.14	0.11	0.10
query13	0.62	0.60	0.59
query14	0.79	0.78	0.81
query15	0.86	0.83	0.83
query16	0.40	0.42	0.40
query17	1.04	1.02	1.09
query18	0.24	0.23	0.24
query19	1.98	1.94	1.89
query20	0.02	0.02	0.01
query21	15.39	0.94	0.59
query22	0.73	0.73	0.62
query23	15.20	1.36	0.64
query24	3.48	0.77	0.50
query25	0.19	0.12	0.07
query26	0.36	0.14	0.14
query27	0.06	0.04	0.04
query28	13.11	1.03	0.44
query29	12.61	3.94	3.23
query30	0.25	0.09	0.06
query31	2.82	0.61	0.38
query32	3.22	0.54	0.46
query33	3.03	3.04	3.01
query34	16.56	5.13	4.63
query35	4.58	4.57	4.57
query36	0.64	0.52	0.47
query37	0.09	0.06	0.05
query38	0.04	0.03	0.04
query39	0.04	0.03	0.02
query40	0.17	0.13	0.13
query41	0.08	0.03	0.03
query42	0.03	0.03	0.02
query43	0.03	0.03	0.03
Total cold run time: 103.77 s
Total hot run time: 28.64 s

[hello-stephen]

BE UT Coverage Report

Increment line coverage 94.12% (32/34) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	45.57% (12782/28049)
Line Coverage	36.41% (114020/313193)
Region Coverage	34.01% (65170/191597)
Branch Coverage	31.04% (34202/110176)

[hello-stephen]

BE Regression && UT Coverage Report

Increment line coverage 94.12% (32/34) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	76.50% (21104/27586)
Line Coverage	69.89% (218218/312227)
Region Coverage	67.81% (130445/192374)
Branch Coverage	61.38% (67947/110690)

[eldenmoon]

run buildall

[doris-robot]

TPC-H: Total hot run time: 32510 ms

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/tpch-tools
Tpch sf100 test result on commit 7c118f144625dc7125e801ed3247c82e14cd9efb, data reload: false

------ Round 1 ----------------------------------
q1	17597	5511	5397	5397
q2	2050	333	167	167
q3	10389	1313	736	736
q4	10207	879	467	467
q5	7646	2373	2120	2120
q6	179	165	137	137
q7	902	764	621	621
q8	9343	1430	1122	1122
q9	5410	4901	4986	4901
q10	6744	2291	1818	1818
q11	464	276	280	276
q12	335	356	211	211
q13	17783	3588	3028	3028
q14	220	227	211	211
q15	529	462	463	462
q16	405	416	372	372
q17	600	861	364	364
q18	7076	6406	6471	6406
q19	1197	944	553	553
q20	333	331	201	201
q21	2897	2191	1965	1965
q22	1055	1042	975	975
Total cold run time: 103361 ms
Total hot run time: 32510 ms

----- Round 2, with runtime_filter_mode=off -----
q1	5504	5434	5428	5428
q2	233	338	230	230
q3	2247	2597	2276	2276
q4	1387	1817	1366	1366
q5	4358	4797	5030	4797
q6	175	179	133	133
q7	2058	2021	1788	1788
q8	2627	2810	2715	2715
q9	7179	7138	7086	7086
q10	3054	3270	2758	2758
q11	566	500	492	492
q12	640	751	590	590
q13	3404	3773	3202	3202
q14	273	297	264	264
q15	532	476	468	468
q16	441	491	451	451
q17	1228	1778	1276	1276
q18	7549	7402	7310	7310
q19	763	1044	1100	1044
q20	2004	2045	1903	1903
q21	5409	4969	4721	4721
q22	1127	1135	1055	1055
Total cold run time: 52758 ms
Total hot run time: 51353 ms

[doris-robot]

TPC-DS: Total hot run time: 190577 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 7c118f144625dc7125e801ed3247c82e14cd9efb, data reload: false

query1	977	384	374	374
query2	6555	1954	1961	1954
query3	6708	218	222	218
query4	33724	23760	23341	23341
query5	4413	642	456	456
query6	278	193	183	183
query7	4629	497	325	325
query8	312	253	243	243
query9	9622	2609	2600	2600
query10	483	319	272	272
query11	18429	15942	15164	15164
query12	160	106	106	106
query13	1658	569	422	422
query14	10996	7243	6693	6693
query15	226	198	189	189
query16	7944	682	505	505
query17	1630	762	628	628
query18	2091	435	340	340
query19	242	190	189	189
query20	123	126	116	116
query21	214	126	105	105
query22	4596	4447	4668	4447
query23	35033	33788	33626	33626
query24	7222	2630	2630	2630
query25	515	486	428	428
query26	1219	283	172	172
query27	1950	480	348	348
query28	5171	2205	2144	2144
query29	758	603	467	467
query30	258	188	160	160
query31	991	867	804	804
query32	77	59	54	54
query33	511	353	293	293
query34	734	829	507	507
query35	778	772	725	725
query36	974	1026	942	942
query37	98	90	70	70
query38	3873	3900	3870	3870
query39	1473	1440	1458	1440
query40	200	115	97	97
query41	49	47	43	43
query42	113	102	106	102
query43	517	537	474	474
query44	1372	818	813	813
query45	182	170	168	168
query46	867	1046	668	668
query47	1874	1892	1821	1821
query48	435	421	367	367
query49	776	544	390	390
query50	673	670	434	434
query51	7283	7090	7127	7090
query52	108	101	93	93
query53	234	262	187	187
query54	553	537	466	466
query55	84	78	79	78
query56	276	270	260	260
query57	1230	1231	1160	1160
query58	233	216	219	216
query59	3028	3040	2979	2979
query60	309	286	259	259
query61	117	116	118	116
query62	779	729	720	720
query63	229	194	194	194
query64	4372	977	664	664
query65	3313	3220	3176	3176
query66	1055	410	307	307
query67	15830	15553	15553	15553
query68	4481	872	567	567
query69	493	310	268	268
query70	1189	1126	1079	1079
query71	470	300	255	255
query72	5587	3753	3846	3753
query73	661	729	358	358
query74	10337	9203	8972	8972
query75	3177	3120	2649	2649
query76	3154	1166	773	773
query77	508	374	289	289
query78	10364	10361	9547	9547
query79	2845	915	612	612
query80	665	529	430	430
query81	507	252	229	229
query82	173	124	93	93
query83	170	172	149	149
query84	242	108	83	83
query85	751	360	302	302
query86	390	312	311	311
query87	4350	4387	4251	4251
query88	5317	2421	2404	2404
query89	391	331	292	292
query90	1966	190	188	188
query91	139	149	113	113
query92	72	56	55	55
query93	2494	934	563	563
query94	675	419	296	296
query95	356	275	275	275
query96	492	607	292	292
query97	3177	3240	3157	3157
query98	240	213	196	196
query99	1350	1460	1331	1331
Total cold run time: 290919 ms
Total hot run time: 190577 ms

[doris-robot]

ClickBench: Total hot run time: 28.8 s

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/clickbench-tools
ClickBench test result on commit 7c118f144625dc7125e801ed3247c82e14cd9efb, data reload: false

query1	0.03	0.04	0.03
query2	0.07	0.03	0.03
query3	0.23	0.07	0.06
query4	1.62	0.10	0.11
query5	0.53	0.51	0.52
query6	1.13	0.72	0.72
query7	0.02	0.01	0.01
query8	0.05	0.03	0.04
query9	0.58	0.49	0.51
query10	0.56	0.55	0.54
query11	0.14	0.11	0.10
query12	0.14	0.10	0.10
query13	0.63	0.59	0.61
query14	0.78	0.80	0.79
query15	0.84	0.84	0.82
query16	0.40	0.38	0.38
query17	1.02	1.09	1.05
query18	0.25	0.23	0.21
query19	1.99	1.88	1.87
query20	0.01	0.01	0.01
query21	15.41	0.87	0.56
query22	0.75	0.71	0.70
query23	15.13	1.40	0.51
query24	3.85	0.70	1.28
query25	0.14	0.15	0.08
query26	0.22	0.16	0.14
query27	0.05	0.04	0.05
query28	13.40	0.98	0.43
query29	12.66	4.03	3.30
query30	0.25	0.09	0.07
query31	2.82	0.58	0.40
query32	3.22	0.54	0.47
query33	3.01	3.07	3.04
query34	16.38	5.11	4.52
query35	4.60	4.62	4.62
query36	0.63	0.49	0.48
query37	0.09	0.06	0.07
query38	0.05	0.04	0.03
query39	0.03	0.02	0.02
query40	0.16	0.13	0.12
query41	0.08	0.02	0.02
query42	0.03	0.03	0.02
query43	0.04	0.03	0.03
Total cold run time: 104.02 s
Total hot run time: 28.8 s

[doris-robot]

BE UT Coverage Report

Increment line coverage 94.12% (32/34) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	45.57% (12782/28049)
Line Coverage	36.40% (114003/313195)
Region Coverage	34.02% (65177/191597)
Branch Coverage	31.05% (34211/110176)

[hello-stephen]

BE Regression && UT Coverage Report

Increment line coverage 94.12% (32/34) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	66.16% (18251/27586)
Line Coverage	57.78% (180419/312229)
Region Coverage	55.48% (106735/192374)
Branch Coverage	49.83% (55161/110690)

[hello-stephen]

BE Regression && UT Coverage Report

Increment line coverage 94.12% (32/34) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	66.16% (18251/27586)
Line Coverage	57.78% (180419/312229)
Region Coverage	55.48% (106735/192374)
Branch Coverage	49.83% (55161/110690)

[hello-stephen]

BE Regression && UT Coverage Report

Increment line coverage 94.12% (32/34) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	66.16% (18251/27586)
Line Coverage	57.78% (180419/312229)
Region Coverage	55.48% (106735/192374)
Branch Coverage	49.83% (55161/110690)

[hello-stephen]

BE Regression && UT Coverage Report

Increment line coverage 94.12% (32/34) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	66.16% (18251/27586)
Line Coverage	57.78% (180419/312229)
Region Coverage	55.48% (106735/192374)
Branch Coverage	49.83% (55161/110690)