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我有一個700K +記錄的表,其中有一個簡單的GROUP BY查詢需要超過35+秒才能執行。我沒有關於如何優化這個的想法。在hsqldb中優化GROUP BY
SELECT TOP 10 called_dn, COUNT(called_dn) FROM reportview.calls_out GROUP BY called_dn;
- 在這裏我想補充
TOP 10
限制網絡傳輸引起的延遲。 - 我有一個索引
called_dn
(hsqldb似乎沒有使用這個)。 called_dn
不可空。reportview.calls_out
是一個緩存表。
這裏的表腳本:
CREATE TABLE calls_out (
pk_global_call_id INTEGER GENERATED BY DEFAULT AS SEQUENCE seq_global_call_id NOT NULL,
sys_global_call_id VARCHAR(65),
call_start TIMESTAMP WITH TIME ZONE NOT NULL,
call_end TIMESTAMP WITH TIME ZONE NOT NULL,
duration_interval INTERVAL HOUR TO SECOND(0),
duration_seconds INTEGER,
call_segments INTEGER,
calling_dn VARCHAR(25) NOT NULL,
called_dn VARCHAR(25) NOT NULL,
called_via_dn VARCHAR(25),
fk_end_status INTEGER NOT NULL,
fk_incoming_queue INTEGER,
call_start_year INTEGER,
call_start_month INTEGER,
call_start_week INTEGER,
call_start_day INTEGER,
call_start_hour INTEGER,
call_start_minute INTEGER,
call_start_second INTEGER,
utc_created TIMESTAMP WITH TIME ZONE,
created_by VARCHAR(25),
utc_modified TIMESTAMP WITH TIME ZONE,
modified_by VARCHAR(25),
PRIMARY KEY (pk_global_call_id),
FOREIGN KEY (fk_incoming_queue)
REFERENCES lookup_incoming_queue(pk_id),
FOREIGN KEY (fk_end_status)
REFERENCES lookup_end_status(pk_id));
我我堅持這樣的表現或者是有什麼我可以嘗試加快這個查詢?
編輯:這裏的查詢計劃,如果有幫助:
isDistinctSelect=[false]
isGrouped=[true]
isAggregated=[true]
columns=[ COLUMN: REPORTVIEW.CALLS_OUT.CALLED_DN not nullable
COUNT arg=[ COLUMN: REPORTVIEW.CALLS_OUT.CALLED_DN nullable]
[range variable 1
join type=INNER
table=CALLS_OUT
cardinality=771855
access=FULL SCAN
join condition = [index=SYS_IDX_SYS_PK_10173_10177]]]
groupColumns=[COLUMN: REPORTVIEW.CALLS_OUT.CALLED_DN]
offset=[VALUE = 0, TYPE = INTEGER]
limit=[VALUE = 10, TYPE = INTEGER]
PARAMETERS=[]
SUBQUERIES[]