Re: Difference in temp table insert performance

In both the queries SQL monitor which you posted, are you inserting rows into same global temporary table?

 As because if they are different then it's not a fair comparison . Even you mentioned second one having indexes on it but still load is faster . What would be the diff in avg rowlength of the data which you are inserting into those two? I think that should also play a role in data load performance.

On Fri, 7 Jan 2022, 10:45 pm Pap, <oracle.developer35_at_gmail.com> wrote:

> Hello Listers, Its version 11.2.0.4 of Oracle. And is planned to move to
> 19C soon.
>
> For one of the third party applications , we see direct path insert into
> the global temporary temp table is taking significant time. Below is sql
> monitor from two of the queries , both of them are loading data into global
> temporary tables and in the first case it's inserting ~500million and in
> second case it's inserting ~700million rows. But what we see is even the
> first case global temporary table holds no indexes in it , it's still
> showing ~84% of the activity in the data load step(plan_line_id - 1). And
> the activity section in the sql monitor showing significant time samples
> for 'direct path read temp' and 'direct path write temp'.
>
> In the second case it's inserting ~747million rows but is not spending
> that much time in the data load part i.e. plan_line_id-1 and also i am not
> seeing those 'direct path read temp' and 'direct path write temp' samples
> there. Even this global temporary has 3- indexes in it.
>
> So we wanted to understand what must be causing this ? and if we could
> make the data load into the global temporary table faster in the first
> case? In the second case I understand it's the HASH join part where we are
> spending a lot of time as it spills to temp and we may not have much option
> at hand but we were expecting at least the data load should not take this
> amount of time.
>
>
> Global Stats
>
> =========================================================================================================================
> | Elapsed | Cpu | IO | Application | Concurrency | Cluster |
> Buffer | Read | Read | Write | Write | Cell |
> | Time(s) | Time(s) | Waits(s) | Waits(s) | Waits(s) | Waits(s) |
> Gets | Reqs | Bytes | Reqs | Bytes | Offload |
>
> =========================================================================================================================
> | 8310 | 5655 | 2655 | 0.02 | 0.00 | 0.01 |
> 209M | 2M | 922GB | 666K | 146GB | 17.36% |
>
> =========================================================================================================================
>
> SQL Plan Monitoring Details (Plan Hash Value=3240266454)
>
> ============================================================================================================================================================================================================================
> | Id | Operation | Name | Rows
> | Cost | Time | Start | Execs | Rows | Read | Read | Write |
> Write | Cell | Mem | Activity | Activity Detail |
> | | | | (Estim)
> | | Active(s) | Active | | (Actual) | Reqs | Bytes | Reqs |
> Bytes | Offload | (Max) | (%) | (# samples) |
>
> ============================================================================================================================================================================================================================
> | 0 | INSERT STATEMENT | |
> | | 7764 | +21 | 1 | 1 | | | |
> | | | 0.16 | Cpu (10) |
> | | | |
> | | | | | | | | |
> | | | | enq: US - contention (1) |
> | | | |
> | | | | | | | | |
> | | | | reliable message (2) |
> | 1 | LOAD AS SELECT | |
> | | 8275 | +21 | 1 | 1 | 336K | 66GB | 666K |
> 146GB | | 543K | 84.93 | Cpu (4325) |
> | | | |
> | | | | | | | | |
> | | | | direct path read temp (1277) |
> | | | |
> | | | | | | | | |
> | | | | direct path write temp (1266) |
> | 2 | FILTER | |
> | | 5380 | +21 | 1 | 545M | | | |
> | | | 0.01 | Cpu (1) |
> | 3 | HASH JOIN | | 1
> | 45M | 5398 | +3 | 1 | 545M | | | |
> | | 21M | 2.94 | Cpu (238) |
> | 4 | PARTITION RANGE ITERATOR | | 761
> | 441 | 1 | +3 | 1 | 270K | | | |
> | | | | |
> | 5 | TABLE ACCESS STORAGE FULL | TSF | 761
> | 441 | 1 | +3 | 2 | 270K | | | |
> | | 7M | | |
> | 6 | HASH JOIN | | 3187
> | 45M | 5398 | +3 | 1 | 557M | | | |
> | | 2M | 4.07 | Cpu (329) |
> | 7 | TABLE ACCESS STORAGE FULL | TTNI | 20
> | 19 | 1 | +3 | 1 | 2430 | | | |
> | | 1M | | |
> | 8 | PARTITION RANGE ITERATOR | | 177M
> | 45M | 5398 | +3 | 1 | 4G | | | |
> | | | | |
> | 9 | TABLE ACCESS STORAGE FULL | TSFE | 177M
> | 45M | 5400 | +1 | 32 | 4G | 1M | 852GB | |
> | 38.65% | 7M | 7.89 | Cpu (565) |
> | | | |
> | | | | | | | | |
> | | | | cell single block physical read (1) |
> | | | |
> | | | | | | | | |
> | | | | cell smart table scan (72) |
>
> ============================================================================================================================================================================================================================
>
>
>
> **********************
>
>
> Global Stats
>
> =========================================================================================================================
> | Elapsed | Cpu | IO | Application | Concurrency | Cluster |
> Buffer | Read | Read | Write | Write | Cell |
> | Time(s) | Time(s) | Waits(s) | Waits(s) | Waits(s) | Waits(s) |
> Gets | Reqs | Bytes | Reqs | Bytes | Offload |
>
> =========================================================================================================================
> | 7620 | 4071 | 3523 | 0.10 | 13 | 12 |
> 2G | 6M | 1TB | 2M | 274GB | 8.26% |
>
> =========================================================================================================================
>
> SQL Plan Monitoring Details (Plan Hash Value=2073160275)
>
> ================================================================================================================================================================================================================================================
> | Id | Operation | Name
> | Rows | Cost | Time | Start | Execs | Rows | Read | Read |
> Write | Write | Cell | Mem | Temp | Activity | Activity
> Detail |
> | | |
> | (Estim) | | Active(s) | Active | | (Actual) | Reqs | Bytes |
> Reqs | Bytes | Offload | (Max) | (Max) | (%) | (#
> samples) |
>
> ================================================================================================================================================================================================================================================
> | 0 | INSERT STATEMENT |
> | | | 6995 | +625 | 1 | 1 | | |
> | | | | | 1.27 | gc buffer busy acquire
> (3) |
> | | |
> | | | | | | | | |
> | | | | | | gc current block busy
> (9) |
> | | |
> | | | | | | | | |
> | | | | | | buffer busy waits (11)
> |
> | | |
> | | | | | | | | |
> | | | | | | enq: SS - contention
> (6) |
> | | |
> | | | | | | | | |
> | | | | | | Cpu (5)
> |
> | | |
> | | | | | | | | |
> | | | | | | DFS lock handle (23)
> |
> | | |
> | | | | | | | | |
> | | | | | | cell single block
> physical read (2) |
> | | |
> | | | | | | | | |
> | | | | | | local write wait (32)
> |
> | | |
> | | | | | | | | |
> | | | | | | read by other session
> (3) |
> | 1 | LOAD AS SELECT |
> | | | 6749 | +871 | 1 | 1 | | |
> 497K | 121GB | | 543K | | 9.24 | Cpu (678)
> |
> | | |
> | | | | | | | | |
> | | | | | | direct path write temp
> (8) |
> | 2 | FILTER |
> | | | 6749 | +871 | 1 | 747M | | |
> | | | | | 0.07 | Cpu (5)
> |
> | 3 | HASH JOIN |
> | 1 | 22M | 7617 | +3 | 1 | 747M | | |
> | | | 2M | | 1.51 | Cpu (112)
> |
> | 4 | VIEW | index$_join$_006
> | 110 | 2 | 1 | +3 | 1 | 112 | | |
> | | | | | |
> |
> | 5 | HASH JOIN |
> | | | 1 | +3 | 1 | 112 | | |
> | | | 2M | | |
> |
> | 6 | INDEX STORAGE FAST FULL SCAN | MMC_IX1
> | 110 | 1 | 1 | +3 | 1 | 112 | | |
> | | | | | |
> |
> | 7 | INDEX STORAGE FAST FULL SCAN | MMC_IX2
> | 110 | 1 | 1 | +3 | 1 | 112 | | |
> | | | | | |
> |
> | 8 | NESTED LOOPS |
> | 1 | 22M | 6749 | +871 | 1 | 747M | | |
> | | | | | 0.39 | Cpu (29)
> |
> | 9 | NESTED LOOPS |
> | 1 | 22M | 6749 | +871 | 1 | 747M | | |
> | | | | | 0.55 | Cpu (41)
> |
> | 10 | HASH JOIN |
> | 1 | 22M | 7620 | +0 | 1 | 747M | 5M | 623GB |
> 1M | 153GB | | 675M | 175G | 69.88 | Cpu (1845)
> |
> | | |
> | | | | | | | | |
> | | | | | | direct path read temp
> (3275) |
> | | |
> | | | | | | | | |
> | | | | | | direct path write temp
> (71) |
> | 11 | HASH JOIN |
> | 1 | 22M | 503 | +1 | 1 | 540M | | |
> | | | 2M | | 2.41 | Cpu (179)
> |
> | 12 | TABLE ACCESS STORAGE FULL | TTFXI
> | 20 | 19 | 1 | +3 | 1 | 6199 | | |
> | | | 1M | | |
> |
> | 13 | PARTITION RANGE ITERATOR |
> | 93M | 22M | 501 | +3 | 1 | 4G | | |
> | | | | | |
> |
> | 14 | TABLE ACCESS STORAGE FULL | TSFEF
> | 93M | 22M | 501 | +3 | 32 | 4G | 582K | 458GB |
> | | 75.25% | 7M | | 1.08 | Cpu (77)
> |
> | | |
> | | | | | | | | |
> | | | | | | cell smart table scan
> (3) |
> | 15 | TABLE ACCESS STORAGE FULL | TTF
> | 1 | 19 | 367 | +503 | 1 | 747M | 238K | 136GB |
> | | 25.37% | 7M | | 0.90 | Cpu (60)
> |
> | | |
> | | | | | | | | |
> | | | | | | cell smart table scan
> (7) |
> | 16 | INDEX UNIQUE SCAN | TMFI_PK
> | 1 | 1 | 6749 | +871 | 747M | 747M | 110 | 880KB |
> | | | | | 8.70 | Cpu (646)
> |
> | 17 | TABLE ACCESS BY INDEX ROWID | TMFI
> | 1 | 2 | 6749 | +871 | 747M | 747M | 16 | 128KB |
> | | | | | 4.01 | Cpu (298)
> |
>
> ================================================================================================================================================================================================================================================
>

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