Re: Review Request 68474: HIVE-20440: Create better cache eviction policy for SmallTableCache

[Sahil Takiar]

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ql/src/java/org/apache/hadoop/hive/ql/exec/spark/SmallTableCache.java
Line 60 (original), 69 (patched)


keep the explicit cache method and call it in `MapJoinOperator#closeOp`. 
This way when a task finishes, we still keep the small table around for at 
least 30 seconds, which gives any tasks scheduled in the future a chance to 
re-use the small table.



ql/src/java/org/apache/hadoop/hive/ql/exec/spark/SmallTableCache.java
Lines 75 (patched)


can u add some javadocs to this class explaining what it is doing



ql/src/java/org/apache/hadoop/hive/ql/exec/spark/SmallTableCache.java
Lines 82 (patched)


rename to something like `cleanupService`



ql/src/java/org/apache/hadoop/hive/ql/exec/spark/SmallTableCache.java
Lines 90 (patched)


nit: make `INTEGER_ONE` a static import



ql/src/java/org/apache/hadoop/hive/ql/exec/spark/SmallTableCache.java
Lines 91 (patched)


"SmallTableCache maintenance thread" -> "SmallTableCache Cleanup Thread"



ql/src/java/org/apache/hadoop/hive/ql/exec/spark/SmallTableCache.java
Lines 117 (patched)


replace with `cacheL1.get(key, valueLoader)` where `valueLoader` loads from 
`cacheL2`


- Sahil Takiar


On Sept. 19, 2018, 11:14 p.m., Antal Sinkovits wrote:
> 
> ---
> This is an automatically generated e-mail. To reply, visit:
> https://reviews.apache.org/r/68474/
> ---
> 
> (Updated Sept. 19, 2018, 11:14 p.m.)
> 
> 
> Review request for hive, Naveen Gangam, Sahil Takiar, Adam Szita, and Xuefu 
> Zhang.
> 
> 
> Repository: hive-git
> 
> 
> Description
> ---
> 
> I've modified the SmallTableCache to use guava cache, with soft references.
> By using a value loader, I've also eliminated the synchronization on the 
> intern-ed string of the path.
> 
> 
> Diffs
> -
> 
>   ql/pom.xml d73deba440702ec39fc5610df28e0fe54baef025 
>   ql/src/java/org/apache/hadoop/hive/ql/exec/spark/HashTableLoader.java 
> cf27e92bafdc63096ec0fa8c3106657bab52f370 
>   ql/src/java/org/apache/hadoop/hive/ql/exec/spark/SmallTableCache.java 
> 3293100af96dc60408c53065fa89143ead98f818 
>   ql/src/test/org/apache/hadoop/hive/ql/exec/spark/TestSmallTableCache.java 
> PRE-CREATION 
> 
> 
> Diff: https://reviews.apache.org/r/68474/diff/2/
> 
> 
> Testing
> ---
> 
> 
> Thanks,
> 
> Antal Sinkovits
> 
>

Re: Review Request 68474: HIVE-20440: Create better cache eviction policy for SmallTableCache

[denys kuzmenko via Review Board]

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ql/src/java/org/apache/hadoop/hive/ql/exec/spark/SmallTableCache.java
Lines 94 (patched)


Just a remark, note from google documentation:
"Because of the performance implications of using soft references, we 
generally recommend using the more predictable maximum cache size instead."


- denys kuzmenko


On Sept. 19, 2018, 11:14 p.m., Antal Sinkovits wrote:
> 
> ---
> This is an automatically generated e-mail. To reply, visit:
> https://reviews.apache.org/r/68474/
> ---
> 
> (Updated Sept. 19, 2018, 11:14 p.m.)
> 
> 
> Review request for hive, Naveen Gangam, Sahil Takiar, Adam Szita, and Xuefu 
> Zhang.
> 
> 
> Repository: hive-git
> 
> 
> Description
> ---
> 
> I've modified the SmallTableCache to use guava cache, with soft references.
> By using a value loader, I've also eliminated the synchronization on the 
> intern-ed string of the path.
> 
> 
> Diffs
> -
> 
>   ql/pom.xml d73deba440702ec39fc5610df28e0fe54baef025 
>   ql/src/java/org/apache/hadoop/hive/ql/exec/spark/HashTableLoader.java 
> cf27e92bafdc63096ec0fa8c3106657bab52f370 
>   ql/src/java/org/apache/hadoop/hive/ql/exec/spark/SmallTableCache.java 
> 3293100af96dc60408c53065fa89143ead98f818 
>   ql/src/test/org/apache/hadoop/hive/ql/exec/spark/TestSmallTableCache.java 
> PRE-CREATION 
> 
> 
> Diff: https://reviews.apache.org/r/68474/diff/2/
> 
> 
> Testing
> ---
> 
> 
> Thanks,
> 
> Antal Sinkovits
> 
>

Re: Review Request 68474: HIVE-20440: Create better cache eviction policy for SmallTableCache

[Antal Sinkovits via Review Board]

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(Updated szept. 19, 2018, 11:14 du)


Review request for hive, Naveen Gangam, Sahil Takiar, Adam Szita, and Xuefu 
Zhang.


Repository: hive-git


Description (updated)
---

I've modified the SmallTableCache to use guava cache, with soft references.
By using a value loader, I've also eliminated the synchronization on the 
intern-ed string of the path.


Diffs (updated)
-

  ql/pom.xml d73deba440702ec39fc5610df28e0fe54baef025 
  ql/src/java/org/apache/hadoop/hive/ql/exec/spark/HashTableLoader.java 
cf27e92bafdc63096ec0fa8c3106657bab52f370 
  ql/src/java/org/apache/hadoop/hive/ql/exec/spark/SmallTableCache.java 
3293100af96dc60408c53065fa89143ead98f818 
  ql/src/test/org/apache/hadoop/hive/ql/exec/spark/TestSmallTableCache.java 
PRE-CREATION 


Diff: https://reviews.apache.org/r/68474/diff/2/

Changes: https://reviews.apache.org/r/68474/diff/1-2/


Testing
---


Thanks,

Antal Sinkovits

Review Request 68474: HIVE-20440: Create better cache eviction policy for SmallTableCache

[Antal Sinkovits via Review Board]

---
This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/68474/
---

Review request for hive, Naveen Gangam, Sahil Takiar, Adam Szita, and Xuefu 
Zhang.


Repository: hive-git


Description
---

I've modified the SmallTableCache to use guava cache, with soft references. 
By using a value loader, I've also eliminated the synchronization on the 
intern-ed string of the path.


Diffs
-

  ql/src/java/org/apache/hadoop/hive/ql/exec/spark/HashTableLoader.java 
cf27e92bafdc63096ec0fa8c3106657bab52f370 
  ql/src/java/org/apache/hadoop/hive/ql/exec/spark/SmallTableCache.java 
3293100af96dc60408c53065fa89143ead98f818 


Diff: https://reviews.apache.org/r/68474/diff/1/


Testing
---


Thanks,

Antal Sinkovits