Re: [HACKERS] path toward faster partition pruning - Mailing list pgsql-hackers

From Beena Emerson
Subject Re: [HACKERS] path toward faster partition pruning
Date
Msg-id CAOG9ApHXqaOb0akH7hB4XePt2B6CU8T54kC7d9GS2S8Qs4sfDw@mail.gmail.com
Whole thread Raw
In response to Re: [HACKERS] path toward faster partition pruning  (Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>)
List 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


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