database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-04 20:11:56 +03:00
Code Activity

Use MINVALUE/MAXVALUE instead of UNBOUNDED for range partition bounds.

Browse Source 
Previously, UNBOUNDED meant no lower bound when used in the FROM list,
and no upper bound when used in the TO list, which was OK for
single-column range partitioning, but problematic with multiple
columns. For example, an upper bound of (10.0, UNBOUNDED) would not be
collocated with a lower bound of (10.0, UNBOUNDED), thus making it
difficult or impossible to define contiguous multi-column range
partitions in some cases.

Fix this by using MINVALUE and MAXVALUE instead of UNBOUNDED to
represent a partition column that is unbounded below or above
respectively. This syntax removes any ambiguity, and ensures that if
one partition's lower bound equals another partition's upper bound,
then the partitions are contiguous.

Also drop the constraint prohibiting finite values after an unbounded
column, and just document the fact that any values after MINVALUE or
MAXVALUE are ignored. Previously it was necessary to repeat UNBOUNDED
multiple times, which was needlessly verbose.

Note: Forces a post-PG 10 beta2 initdb.

Report by Amul Sul, original patch by Amit Langote with some
additional hacking by me.

Discussion: https://postgr.es/m/CAAJ_b947mowpLdxL3jo3YLKngRjrq9+Ej4ymduQTfYR+8=YAYQ@mail.gmail.com
This commit is contained in:
Dean Rasheed
2017-07-21 09:20:47 +01:00
parent 866f4a7c21
commit d363d42bb9
18 changed files with 378 additions and 238 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
src/include/nodes/parsenodes.h
View File

@@ -809,16 +809,24 @@ typedef struct PartitionBoundSpec
} PartitionBoundSpec;
/*
* PartitionRangeDatum - can be either a value or UNBOUNDED
* PartitionRangeDatum - one of the values in a range partition bound
*
* "value" is an A_Const in raw grammar output, a Const after analysis
* This can be MINVALUE, MAXVALUE or a specific bounded value.
*/
typedef enum PartitionRangeDatumKind
{
PARTITION_RANGE_DATUM_MINVALUE = -1, /* less than any other value */
PARTITION_RANGE_DATUM_VALUE = 0, /* a specific (bounded) value */
PARTITION_RANGE_DATUM_MAXVALUE = 1 /* greater than any other value */
} PartitionRangeDatumKind;
typedef struct PartitionRangeDatum
{
NodeTag type;
bool infinite; /* true if UNBOUNDED */
Node *value; /* null if UNBOUNDED */
PartitionRangeDatumKind kind;
Node *value; /* Const (or A_Const in raw tree), if kind is
* PARTITION_RANGE_DATUM_VALUE, else NULL */
int location; /* token location, or -1 if unknown */
} PartitionRangeDatum;