8.1.2 Execution Plan
The Execution Plan shows the SQL optimizer's query execution path. Execution Plan output is generated using EXPLAIN PLAN and DBMS_XPLAN.
Yes, it is possible to have a different actual plan. Example:
create table t1 (c1 number);
insert into t1 ...
Taking into consideration all combinations of predicates can be used
One option would be a bitmap index on the non ID, non TIMESTAMP column.
One index per column.
Beware of its it's downsides.
possible slower DML
Luckily, the newer versions of Oracle allow you to experiment with indexing strategies.
I agree with @J.D. said about temp table variables. Because until SQL Server 2019 version, Query Engine thinks the estimate of temp table variables only returns one row.
Otherwise, I think you should leave also Clustered Index Scan on anotherbigtable. Because it cost 98%
I didn't know your indexes, but I recommend the index below.
CREATE INDEX ...
The first thing I would do is avoid using table variables in heavy SQL operations. You should use a temp table instead. Either initially or select your table variable @table1 into a temp table then use that temp table in your update statement.
Table variables are historically known to be bottlenecks because statistics aren't maintained on them, and even with ...
You might want to look into using Spark, and if are able to introduce AWS into the architecture, Kinesis Data Firehouse.
Another article on Spark: https://www.influxdata.com/blog/zeppelin-spark-and-influxdb-for-big-data-time-...
@Siva There's a lot of good information for determining memory pressure in this StackExchange question I asked in the past: What steps can I take to determine if my server is under-provisioned for memory?
In summary, on my server, looking at the DMV sys.dm_os_wait_stats to see the top wait types were memory related and then cross checking that with the ...
Use the MemoryManagerInfo stored procedure, which can be found here:
It provides nice breakdown of how SQL Server currently uses memory:
See example on this picture below - this is what my server is currently consuming:
Roughly, Total Server Memory = Database Cache Memory + Free Memory + Stolen ...
How do you define "utilized"? A page that was read into cache a second ago, would that be counted as utilized? A minute ago? An hour? A week?
The point is that there is no such things as "utilized". SQL server keep pages (and other stuff) in memory. When when there is memory pressure (internal or external) a traditional cache aging ...
how do we check/calculate the SQL memory that is currently consumed on the instance.
That is quite simple to do. You have DMV sys.dm_os_process_memory that will give you the information. It will give you physical memory used and total memory used (RAM+Page file)
select (physical_memory_in_use_kb/1024) as Phy_Mem_used_MB, (...