Horton

Re: path toward faster partition pruning

Beena Emerson <memissemerson@gmail.com>

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From: Beena Emerson <memissemerson@gmail.com>
To: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Cc: Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, David Rowley <david.rowley@2ndquadrant.com>, Dilip Kumar <dilipbalaut@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2017-10-26T04:40:21Z
Lists: pgsql-hackers 
Hello,

On Wed, Oct 25, 2017 at 1:07 PM, Amit Langote
<Langote_Amit_f8@lab.ntt.co.jp> wrote:
> On 2017/10/25 15:47, Amit Langote wrote:
>> On 2017/10/24 1:38, Beena Emerson wrote:
>>> I had noticed this and also that this crash:
>>>
>>> tprt PARTITION BY RANGE(Col1)
>>>        tprt_1 FOR VALUES FROM (1) TO (50001) PARTITION BY RANGE(Col1)
>>>               tprt_11 FOR VALUES FROM (1) TO (10000),
>>>               tprt_1d DEFAULT
>>>        tprt_2 FOR VALUES FROM (50001) TO (100001)
>>>
>>> EXPLAIN (COSTS OFF) SELECT * FROM tprt WHERE col1 BETWEEN 20000 AND 70000;
>>> server closed the connection unexpectedly
>>> This probably means the server terminated abnormally
>>> before or while processing the request.
>>> The connection to the server was lost. Attempting reset: Failed.
>>> !>
>>
>> ...and this (crash) were due to bugs in the 0005 patch.
>
> [ .... ]
>
>> Should be fixed in the attached updated version.
>
> Oops, not quite.  The crash that Beena reported wasn't fixed (or rather
> reintroduced by some unrelated change after once confirming it was fixed).
>
> Really fixed this time.

Some minor comments:

1. wrong function name (0003)

The comment on function get_partitions_from_clauses_guts uses wrong name:
instead of "_from_", "_using_" is written.

 /*
+ * get_partitions_using_clauses_guts
+ *     Determine relation's partitions that satisfy *all* of the clauses
+ *     in the list (return value describes the set of such partitions)
+ *

2. typo information (0003)

+/*
+ * classify_partition_bounding_keys
+ *     Classify partition clauses into equal, min, max keys, along with any
+ *     Nullness constraints and return that informatin in the output argument

3. misspell admissible (0003)
+    * columns, whereas a prefix of all partition key columns is addmissible
+    * as min and max keys.

4. double and? (0002)
+                * as part of the operator family, check if its negator
+                * exists and and that the latter is compatible with

5. typo inequality (0002)
+                * (key < val OR key > val), if the partitioning method
+                * supports such notion of inequlity.


6. typo output (0005)
+    * return it as the only scannable partition, that means the query
+    * doesn't want null values in its outout.

7. typo provide (0005)
+   /* Valid keys->eqkeys must provoide all partition keys. */
+   Assert(keys->n_eqkeys == 0 || keys->n_eqkeys == partkey->partnatts);

8. comment of struct PartClause (0003)
+/*
+ * Information about a clause matched with a partition key column kept to
+ * avoid repeated recomputation in remove_redundant_clauses().
+ */

Instead of repeated recomputation, we can use just  " repeated
computation" or just " recomputation"



-- 

Beena Emerson

EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Fix assorted partition pruning bugs

  2. Make gen_partprune_steps static

  3. Remove useless 'default' clause

  4. Reorganize partitioning code

  5. Use custom hash opclass for hash partition pruning

  6. Blindly attempt to fix sepgsql tests broken due to 9fdb675fc5.

  7. Attempt to fix endianess issues in new hash partition test.

  8. Faster partition pruning

  9. For partitionwise join, match on partcollation, not parttypcoll.

  10. Revise API for partition bound search functions.

  11. Revise API for partition_rbound_cmp/partition_rbound_datum_cmp.

  12. Fix possible crash in partition-wise join.

  13. Refactor code for partition bound searching

  14. New C function: bms_add_range

  15. Add extensive tests for partition pruning.

  16. Add null test to partition constraint for default range partitions.

  17. Remove BufFile's isTemp flag.

  18. Make OWNER TO subcommand mention consistent

  19. Fix index matching for operators with mixed collatable/noncollatable inputs.