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authorRobert Haas <rhaas@postgresql.org>2017-11-09 18:07:25 -0500
committerRobert Haas <rhaas@postgresql.org>2017-11-09 18:07:44 -0500
commit1aba8e651ac3e37e1d2d875842de1e0ed22a651e (patch)
tree0668a250bea6bd7d872f466cb653c4cbd378e7b5 /src/backend/parser/parse_utilcmd.c
parente7397f015c9589f95f5f5b48d7a274b2f1628971 (diff)
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Add hash partitioning.
Hash partitioning is useful when you want to partition a growing data set evenly. This can be useful to keep table sizes reasonable, which makes maintenance operations such as VACUUM faster, or to enable partition-wise join. At present, we still depend on constraint exclusion for partitioning pruning, and the shape of the partition constraints for hash partitioning is such that that doesn't work. Work is underway to fix that, which should both improve performance and make partitioning pruning work with hash partitioning. Amul Sul, reviewed and tested by Dilip Kumar, Ashutosh Bapat, Yugo Nagata, Rajkumar Raghuwanshi, Jesper Pedersen, and by me. A few final tweaks also by me. Discussion: http://postgr.es/m/CAAJ_b96fhpJAP=ALbETmeLk1Uni_GFZD938zgenhF49qgDTjaQ@mail.gmail.com
Diffstat (limited to 'src/backend/parser/parse_utilcmd.c')
-rw-r--r--src/backend/parser/parse_utilcmd.c29
1 files changed, 27 insertions, 2 deletions
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 30fc2d9ff84..8461da490ac 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -3310,6 +3310,11 @@ transformPartitionBound(ParseState *pstate, Relation parent,
if (spec->is_default)
{
+ if (strategy == PARTITION_STRATEGY_HASH)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+ errmsg("a hash-partitioned table may not have a default partition")));
+
/*
* In case of the default partition, parser had no way to identify the
* partition strategy. Assign the parent's strategy to the default
@@ -3320,7 +3325,27 @@ transformPartitionBound(ParseState *pstate, Relation parent,
return result_spec;
}
- if (strategy == PARTITION_STRATEGY_LIST)
+ if (strategy == PARTITION_STRATEGY_HASH)
+ {
+ if (spec->strategy != PARTITION_STRATEGY_HASH)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+ errmsg("invalid bound specification for a hash partition"),
+ parser_errposition(pstate, exprLocation((Node *) spec))));
+
+ if (spec->modulus <= 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+ errmsg("modulus for hash partition must be a positive integer")));
+
+ Assert(spec->remainder >= 0);
+
+ if (spec->remainder >= spec->modulus)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+ errmsg("remainder for hash partition must be less than modulus")));
+ }
+ else if (strategy == PARTITION_STRATEGY_LIST)
{
ListCell *cell;
char *colname;
@@ -3485,7 +3510,7 @@ transformPartitionBound(ParseState *pstate, Relation parent,
static void
validateInfiniteBounds(ParseState *pstate, List *blist)
{
- ListCell *lc;
+ ListCell *lc;
PartitionRangeDatumKind kind = PARTITION_RANGE_DATUM_VALUE;
foreach(lc, blist)