Solution : https://service.sap.com/sap/support/notes/1224682 (SAP Service marketplace login required)
Key words : 
paket tabname clu_size  com_block task_numb job_numb parabclu xparlock150   bkpf    00300000  00060000  04        04      0020since, paket tabname clu_size  com_block task_numb job_numb parabclu xparlock150   bkpf    00000020  00000004  04        04      0020, tab_name glpca clu_size 99990000 com_block 00100000 task_numb 04 job_numb 04 parabclu 0020 xparlock, fields- clu_size- task_numb- job_numb- parabclu- xparlockcan, test system production system data volume 181209319 183415423 number, table ewuclstat field high-limit, 'select count' takes place, deactivate parallel processing explicitly, task_numb = '00' - selection task, ewuclstat-limit-high
Related Notes : 
       
| 1539473 | LCC optimization - General questions/answers (FAQ) | 
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| 433167 | Cluster euro: REUCLDOC does not write any clusters | 
| 400488 | Changes in EWUCLCT during the conversion phase? | 
| 397398 | Cluster: enqueue problem in the syslog is recognizable | 
| 384167 | Buffer synchronization; deactivate buffering for table ... | 
| 315196 | Cluster: Restart after system shutdown in Conversion phase | 
| 204338 | Problems with table EWUCLU after upgrade/euro changeover | 
| 202780 | Termin. VBAK, VBRK, EIKP, EKKO, AUAK due to memory overflow | 
| 189908 | Cluster: Change by means of program ZEWUCLCT | 
| 183158 | LC changeover to euro: Cluster functions | 
| 181476 | Cluster:Parallel processing on table level, performance | 
| 173993 | Cluster: System settings during Euro LC changeover | 
| 173846 | Cluster: Deadlock occurred in phase CONVERSION | 
| 168728 | Cluster: No. of clusters exceeds maximum |