[fix](connection)Add more log for Reach limit of connections

[Jibing-Li]

What problem does this PR solve?

Add more log to investigate Reach limit of connections exception.

Issue Number: close #xxx

Related PR: #xxx

Problem Summary:

Release note

None

Check List (For Author)

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:
    • This is a refactor/code format and no logic has been changed.
    • Previous test can cover this change.
    • No code files have been changed.
    • Other reason

• Behavior changed:

  • No.
  • Yes.

• Does this need documentation?

  • No.
  • Yes.

Check List (For Reviewer who merge this PR)

• Confirm the release note
• Confirm test cases
• Confirm document
• Add branch pick label

[Thearas]

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?

[Jibing-Li]

run buildall

[github-actions]

PR approved by at least one committer and no changes requested.

[github-actions]

PR approved by anyone and no changes requested.

[doris-robot]

TPC-H: Total hot run time: 32753 ms

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/tpch-tools
Tpch sf100 test result on commit 49259b1cec0cab09df1aecdc739d45169e7073ae, data reload: false

------ Round 1 ----------------------------------
q1	17560	6053	6001	6001
q2	2050	309	175	175
q3	10427	1248	756	756
q4	10317	877	437	437
q5	8020	2187	2004	2004
q6	211	186	146	146
q7	886	749	604	604
q8	9227	1331	1171	1171
q9	5196	4942	4957	4942
q10	6779	2337	1872	1872
q11	486	277	255	255
q12	352	366	213	213
q13	17899	3613	3030	3030
q14	250	248	217	217
q15	564	518	497	497
q16	633	616	578	578
q17	567	851	325	325
q18	6942	6469	6420	6420
q19	1941	1046	574	574
q20	317	323	199	199
q21	2977	2228	2016	2016
q22	388	344	321	321
Total cold run time: 103989 ms
Total hot run time: 32753 ms

----- Round 2, with runtime_filter_mode=off -----
q1	6218	6190	6282	6190
q2	266	347	247	247
q3	2530	2885	2561	2561
q4	1506	2023	1477	1477
q5	4621	4991	4996	4991
q6	194	176	139	139
q7	2135	1996	1788	1788
q8	2642	2781	2708	2708
q9	7422	7294	7333	7294
q10	3090	3376	2783	2783
q11	595	516	497	497
q12	645	777	599	599
q13	3365	3671	3118	3118
q14	287	305	282	282
q15	583	524	503	503
q16	646	678	661	661
q17	1234	1721	1269	1269
q18	7764	7558	7221	7221
q19	842	1158	1087	1087
q20	1966	2075	1910	1910
q21	5684	5234	5065	5065
q22	649	655	608	608
Total cold run time: 54884 ms
Total hot run time: 52998 ms

[doris-robot]

TPC-DS: Total hot run time: 196951 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 49259b1cec0cab09df1aecdc739d45169e7073ae, data reload: false

query1	1306	954	950	950
query2	6536	2300	2362	2300
query3	11069	4840	4894	4840
query4	32675	23851	23567	23567
query5	4369	615	453	453
query6	281	200	195	195
query7	3998	484	307	307
query8	303	252	233	233
query9	9503	2776	2725	2725
query10	474	322	264	264
query11	18058	15734	15141	15141
query12	157	108	104	104
query13	1665	547	427	427
query14	11568	7490	7402	7402
query15	249	219	188	188
query16	7137	652	472	472
query17	1560	757	612	612
query18	1239	378	333	333
query19	240	195	167	167
query20	121	118	112	112
query21	209	135	113	113
query22	4735	4643	4817	4643
query23	34245	33445	33456	33445
query24	6398	2296	2392	2296
query25	466	455	389	389
query26	717	273	159	159
query27	2087	476	327	327
query28	5679	2506	2509	2506
query29	545	558	437	437
query30	217	185	150	150
query31	994	926	838	838
query32	88	65	57	57
query33	476	348	286	286
query34	747	886	515	515
query35	821	849	747	747
query36	1041	1064	981	981
query37	111	97	78	78
query38	4301	4110	4194	4110
query39	1505	1500	1470	1470
query40	200	109	107	107
query41	44	42	44	42
query42	115	107	101	101
query43	531	525	488	488
query44	1279	829	835	829
query45	179	172	165	165
query46	882	1071	664	664
query47	2013	2040	1985	1985
query48	381	426	331	331
query49	697	498	396	396
query50	642	701	379	379
query51	7268	7346	7045	7045
query52	104	113	90	90
query53	228	248	179	179
query54	473	486	415	415
query55	84	91	84	84
query56	277	275	265	265
query57	1255	1252	1163	1163
query58	237	229	233	229
query59	3237	3205	3045	3045
query60	272	259	254	254
query61	119	105	109	105
query62	860	842	754	754
query63	236	193	195	193
query64	2831	1104	649	649
query65	3286	3230	3245	3230
query66	822	414	306	306
query67	16287	15865	15583	15583
query68	9017	746	526	526
query69	471	294	242	242
query70	1212	1205	1137	1137
query71	436	294	255	255
query72	5917	3812	3805	3805
query73	647	746	361	361
query74	10290	9351	8782	8782
query75	4722	3140	2655	2655
query76	5052	1172	760	760
query77	922	355	288	288
query78	10102	10149	9662	9662
query79	3536	840	590	590
query80	808	513	425	425
query81	489	278	225	225
query82	493	151	124	124
query83	181	160	141	141
query84	279	88	75	75
query85	760	368	295	295
query86	353	320	305	305
query87	4615	4471	4366	4366
query88	3199	2298	2233	2233
query89	424	338	289	289
query90	2047	186	178	178
query91	144	129	101	101
query92	64	58	50	50
query93	1781	877	530	530
query94	673	378	293	293
query95	331	263	246	246
query96	477	608	277	277
query97	2714	2834	2681	2681
query98	228	204	189	189
query99	1615	1545	1450	1450
Total cold run time: 296728 ms
Total hot run time: 196951 ms

[doris-robot]

ClickBench: Total hot run time: 31.7 s

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/clickbench-tools
ClickBench test result on commit 49259b1cec0cab09df1aecdc739d45169e7073ae, data reload: false

query1	0.04	0.03	0.03
query2	0.08	0.03	0.04
query3	0.23	0.08	0.07
query4	1.62	0.10	0.10
query5	0.42	0.43	0.40
query6	1.17	0.65	0.65
query7	0.02	0.02	0.01
query8	0.03	0.04	0.03
query9	0.58	0.50	0.53
query10	0.56	0.57	0.56
query11	0.15	0.10	0.11
query12	0.14	0.11	0.10
query13	0.61	0.61	0.59
query14	2.83	2.85	2.85
query15	0.91	0.82	0.81
query16	0.38	0.39	0.38
query17	1.06	1.02	1.05
query18	0.22	0.22	0.21
query19	1.92	1.86	2.00
query20	0.01	0.01	0.02
query21	15.36	0.91	0.59
query22	0.75	0.82	0.69
query23	15.21	1.44	0.55
query24	2.58	2.29	1.15
query25	0.23	0.11	0.13
query26	0.23	0.16	0.15
query27	0.06	0.05	0.07
query28	14.45	1.50	1.05
query29	12.55	3.96	3.28
query30	0.24	0.09	0.06
query31	2.84	0.60	0.39
query32	3.23	0.55	0.46
query33	3.15	3.03	3.20
query34	16.82	5.14	4.54
query35	4.51	4.51	4.50
query36	0.64	0.49	0.49
query37	0.09	0.05	0.05
query38	0.04	0.03	0.04
query39	0.04	0.02	0.02
query40	0.17	0.14	0.13
query41	0.08	0.03	0.02
query42	0.03	0.03	0.02
query43	0.04	0.03	0.03
Total cold run time: 106.32 s
Total hot run time: 31.7 s

[shuke987]

LGTM