oracle /*+ no_parallel(t)相关问题
在检查磁盘读取较多的SQL语句时
select disk_reads,sql_text from (select sql_text,disk_reads,dense_rank() ov
er(order by disk_reads desc) disk_reads_rank from v$sql) where disk_reads_rank <
=10;
发现如下的SQL:
220
select /*+ no_parallel(t) no_parallel_index(t) dbms_stats cursor_sharing_exact u
se_weak_name_resl dynamic_sampling(0) no_monitoring */ count(*),sum(sys_op_opnsi
ze("LOG_ID")),substrb(dump(min("LOG_ID"),16,0,32),1,120),substrb(dump(max("LOG_I
D"),16,0,32),1,120),count("TITLE"),count(distinct "TITLE"),sum(sys_op_opnsize("T
ITLE")),substrb(dump(min(substrb("TITLE",1,32)),16,0,32),1,120),substrb(dump(max
(substrb("TITLE",1,32)),16,0,32),1,120),count(distinct "CONTENT"),sum(sys_op_opn
size("CONTENT")),substrb(dump(min(substrb("CONTENT",1,32)),16,0,32),1,120),subst
rb(dump(max(substrb("CONTENT",1,32)),16,0,32),1,120),count("MEMBER_ID"),count(di
stinct "MEMBER_ID"),sum(sys_op_opnsize("MEMBER_ID")),substrb(dump(min("MEMBER_ID
"),16,0,32),1,120),substrb(dump(max("MEMBER_ID"),16,0,32),1,120),count(distinct
"CREATETIME"),substrb(dump(min("CREATETIME"),16,0,32),1,120),substrb(dump(max("C
REATETIME"),16,0,32),1,120),count(distinct "CREATEID"),sum(sys_op_opnsize("CREAT
EID")),substrb(dump(min("CREATEID"),16,0
小妹对于这些刚接触,不了解这个SQL语句里的
no_parallel(t) no_parallel_index(t) dbms_stats cursor_sharing_exact u
se_weak_name_resl dynamic_sampling(0) no_monitoring
是什么含义,结合上下还是不了解这句SQL是什么意思,希望各位能指点一二,在此先谢谢各位!