[firebase-br] Ajuda para otimizar uma PLAN ( problemas com fb2 )

[Fernando Reis Guimarães]

Pessoal to tendo um problemão aqui com os planos gerados aqui.
Quando executo a query abaixo ( sem ordenar ) executa em 15ms

select
    MESANO,
    NOME
from v_cmi
where medidor = 'ABF024037490'

___________________________________________________________________________
Plan
PLAN JOIN (V_CMI CLL INDEX (C2H_CLL_MEDIDOR), V_CMI CMI INDEX (PK_C2H_CMI))

Adapted Plan
PLAN JOIN (V_CMI CLL INDEX (C2H_CLL_MEDIDOR), V_CMI CMI INDEX (PK_C2H_CMI))

------ Performance info ------
Prepare time = 0ms
Execute time = 16ms
Avg fetch time = 1,78 ms
Current memory = 1.551.240
Max memory = 5.875.368
Memory buffers = 2.048
Reads from disk to cache = 28
Writes from cache to disk = 0
Fetches from cache = 78







Mas quando ordeno leva quase 1 segundo.
Porque está ocorrendo isso?

select
    MESANO,
    NOME
from v_cmi
where medidor = 'ABF024037490'
order by mesano
___________________________________________________________________________
Plan
PLAN JOIN (V_CMI CLL ORDER C2H_CLL_MESANO INDEX (C2H_CLL_MEDIDOR), V_CMI CMI
INDEX (PK_C2H_CMI))

Adapted Plan
PLAN JOIN (V_CMI CLL ORDER C2H_CLL_MESANO INDEX (C2H_CLL_MEDIDOR), V_CMI CMI
INDEX (PK_C2H_CMI))

------ Performance info ------
Prepare time = 16ms
Execute time = 891ms
Avg fetch time = 99,00 ms
Current memory = 1.553.120
Max memory = 5.875.368
Memory buffers = 2.048
Reads from disk to cache = 4.500
Writes from cache to disk = 0
Fetches from cache = 4.563


-- 
Atenciosamente,
Fernando Reis Guimarães.

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