Hi Aleksander,

On Tue, 28 Feb 2017 18:05:36 +0300
Aleksander Alekseev <a.aleks...@postgrespro.ru> wrote:

> Hi, Yugo.
> 
> Looks like a great feature! I'm going to take a closer look on your code
> and write a feedback shortly. For now I can only tell that you forgot
> to include some documentation in the patch.

Thank you for looking into it. I'm forward to your feedback.
This is a proof of concept patch and additional documentation
is not included. I'll add this after reaching a consensus
on the specification of the feature.

> 
> I've added a corresponding entry to current commitfest [1]. Hope you
> don't mind. If it's not too much trouble could you please register on a
> commitfest site and add yourself to this entry as an author? I'm pretty
> sure someone is using this information for writing release notes or
> something like this.

Thank you for registering it to the commitfest. I have added me as an auther.

> 
> [1] https://commitfest.postgresql.org/13/1059/
> 
> On Tue, Feb 28, 2017 at 11:33:13PM +0900, Yugo Nagata wrote:
> > Hi all,
> > 
> > Now we have a declarative partitioning, but hash partitioning is not
> > implemented yet. Attached is a POC patch to add the hash partitioning
> > feature. I know we will need more discussions about the syntax and other
> > specifications before going ahead the project, but I think this runnable
> > code might help to discuss what and how we implement this.
> > 
> > * Description
> > 
> > In this patch, the hash partitioning implementation is basically based
> > on the list partitioning mechanism. However, partition bounds cannot be
> > specified explicitly, but this is used internally as hash partition
> > index, which is calculated when a partition is created or attached.
> > 
> > The tentative syntax to create a partitioned table is as bellow;
> > 
> >  CREATE TABLE h (i int) PARTITION BY HASH(i) PARTITIONS 3 USING hashint4;
> > 
> > The number of partitions is specified by PARTITIONS, which is currently
> > constant and cannot be changed, but I think this is needed to be changed in
> > some manner. A hash function is specified by USING. Maybe, specifying hash
> > function may be ommitted, and in this case, a default hash function
> > corresponding to key type will be used.
> > 
> > A partition table can be create as bellow;
> > 
> >  CREATE TABLE h1 PARTITION OF h;
> >  CREATE TABLE h2 PARTITION OF h;
> >  CREATE TABLE h3 PARTITION OF h;
> > 
> > FOR VALUES clause cannot be used, and the partition bound is
> > calclulated automatically as partition index of single integer value.
> > 
> > When trying create partitions more than the number specified
> > by PARTITIONS, it gets an error.
> > 
> > postgres=# create table h4 partition of h;
> > ERROR:  cannot create hash partition more than 3 for h
> > 
> > An inserted record is stored in a partition whose index equals
> > abs(hashfunc(key)) % <number_of_partitions>. In the above
> > example, this is abs(hashint4(i))%3.
> > 
> > postgres=# insert into h (select generate_series(0,20));
> > INSERT 0 21
> > 
> > postgres=# select *,tableoid::regclass from h;
> >  i  | tableoid 
> > ----+----------
> >   0 | h1
> >   1 | h1
> >   2 | h1
> >   4 | h1
> >   8 | h1
> >  10 | h1
> >  11 | h1
> >  14 | h1
> >  15 | h1
> >  17 | h1
> >  20 | h1
> >   5 | h2
> >  12 | h2
> >  13 | h2
> >  16 | h2
> >  19 | h2
> >   3 | h3
> >   6 | h3
> >   7 | h3
> >   9 | h3
> >  18 | h3
> > (21 rows)
> > 
> > * Todo / discussions
> > 
> > In this patch, we cannot change the number of partitions specified
> > by PARTITIONS. I we can change this, the partitioning rule
> > (<partition index> = abs(hashfunc(key)) % <number_of_partitions>)
> > is also changed and then we need reallocatiing records between
> > partitions.
> > 
> > In this patch, user can specify a hash function USING. However,
> > we migth need default hash functions which are useful and
> > proper for hash partitioning. 
> > 
> > Currently, even when we issue SELECT query with a condition,
> > postgres looks into all partitions regardless of each partition's
> > constraint, because this is complicated such like "abs(hashint4(i))%3 = 0".
> > 
> > postgres=# explain select * from h where i = 10;
> >                         QUERY PLAN                        
> > ----------------------------------------------------------
> >  Append  (cost=0.00..125.62 rows=40 width=4)
> >    ->  Seq Scan on h  (cost=0.00..0.00 rows=1 width=4)
> >          Filter: (i = 10)
> >    ->  Seq Scan on h1  (cost=0.00..41.88 rows=13 width=4)
> >          Filter: (i = 10)
> >    ->  Seq Scan on h2  (cost=0.00..41.88 rows=13 width=4)
> >          Filter: (i = 10)
> >    ->  Seq Scan on h3  (cost=0.00..41.88 rows=13 width=4)
> >          Filter: (i = 10)
> > (9 rows)
> > 
> > However, if we modify a condition into a same expression
> > as the partitions constraint, postgres can exclude unrelated
> > table from search targets. So, we might avoid the problem
> > by converting the qual properly before calling predicate_refuted_by().
> > 
> > postgres=# explain select * from h where abs(hashint4(i))%3 = 
> > abs(hashint4(10))%3;
> >                         QUERY PLAN                        
> > ----------------------------------------------------------
> >  Append  (cost=0.00..61.00 rows=14 width=4)
> >    ->  Seq Scan on h  (cost=0.00..0.00 rows=1 width=4)
> >          Filter: ((abs(hashint4(i)) % 3) = 2)
> >    ->  Seq Scan on h3  (cost=0.00..61.00 rows=13 width=4)
> >          Filter: ((abs(hashint4(i)) % 3) = 2)
> > (5 rows)
> > 
> > Best regards,
> > Yugo Nagata
> > 
> > -- 
> > Yugo Nagata <nag...@sraoss.co.jp>
> 
> > diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
> > index 41c0056..3820920 100644
> > --- a/src/backend/catalog/heap.c
> > +++ b/src/backend/catalog/heap.c
> > @@ -3074,7 +3074,7 @@ StorePartitionKey(Relation rel,
> >                               AttrNumber *partattrs,
> >                               List *partexprs,
> >                               Oid *partopclass,
> > -                             Oid *partcollation)
> > +                             Oid *partcollation, int16 partnparts, Oid 
> > hashfunc)
> >  {
> >     int                     i;
> >     int2vector *partattrs_vec;
> > @@ -3121,6 +3121,8 @@ StorePartitionKey(Relation rel,
> >     values[Anum_pg_partitioned_table_partrelid - 1] = 
> > ObjectIdGetDatum(RelationGetRelid(rel));
> >     values[Anum_pg_partitioned_table_partstrat - 1] = 
> > CharGetDatum(strategy);
> >     values[Anum_pg_partitioned_table_partnatts - 1] = 
> > Int16GetDatum(partnatts);
> > +   values[Anum_pg_partitioned_table_partnparts - 1] = 
> > Int16GetDatum(partnparts);
> > +   values[Anum_pg_partitioned_table_parthashfunc - 1] = 
> > ObjectIdGetDatum(hashfunc);
> >     values[Anum_pg_partitioned_table_partattrs - 1] = 
> > PointerGetDatum(partattrs_vec);
> >     values[Anum_pg_partitioned_table_partclass - 1] = 
> > PointerGetDatum(partopclass_vec);
> >     values[Anum_pg_partitioned_table_partcollation - 1] = 
> > PointerGetDatum(partcollation_vec);
> > diff --git a/src/backend/catalog/partition.c 
> > b/src/backend/catalog/partition.c
> > index 4bcef58..24e69c6 100644
> > --- a/src/backend/catalog/partition.c
> > +++ b/src/backend/catalog/partition.c
> > @@ -36,6 +36,8 @@
> >  #include "optimizer/clauses.h"
> >  #include "optimizer/planmain.h"
> >  #include "optimizer/var.h"
> > +#include "parser/parse_func.h"
> > +#include "parser/parse_oper.h"
> >  #include "rewrite/rewriteManip.h"
> >  #include "storage/lmgr.h"
> >  #include "utils/array.h"
> > @@ -120,6 +122,7 @@ static int32 qsort_partition_rbound_cmp(const void *a, 
> > const void *b,
> >  
> >  static List *get_qual_for_list(PartitionKey key, PartitionBoundSpec *spec);
> >  static List *get_qual_for_range(PartitionKey key, PartitionBoundSpec 
> > *spec);
> > +static List *get_qual_for_hash(PartitionKey key, PartitionBoundSpec *spec);
> >  static Oid get_partition_operator(PartitionKey key, int col,
> >                                        StrategyNumber strategy, bool 
> > *need_relabel);
> >  static List *generate_partition_qual(Relation rel);
> > @@ -236,7 +239,8 @@ RelationBuildPartitionDesc(Relation rel)
> >                     oids[i++] = lfirst_oid(cell);
> >  
> >             /* Convert from node to the internal representation */
> > -           if (key->strategy == PARTITION_STRATEGY_LIST)
> > +           if (key->strategy == PARTITION_STRATEGY_LIST ||
> > +                   key->strategy == PARTITION_STRATEGY_HASH)
> >             {
> >                     List       *non_null_values = NIL;
> >  
> > @@ -251,7 +255,7 @@ RelationBuildPartitionDesc(Relation rel)
> >                             ListCell   *c;
> >                             PartitionBoundSpec *spec = lfirst(cell);
> >  
> > -                           if (spec->strategy != PARTITION_STRATEGY_LIST)
> > +                           if (spec->strategy != key->strategy)
> >                                     elog(ERROR, "invalid strategy in 
> > partition bound spec");
> >  
> >                             foreach(c, spec->listdatums)
> > @@ -464,6 +468,7 @@ RelationBuildPartitionDesc(Relation rel)
> >             switch (key->strategy)
> >             {
> >                     case PARTITION_STRATEGY_LIST:
> > +                   case PARTITION_STRATEGY_HASH:
> >                             {
> >                                     boundinfo->has_null = found_null;
> >                                     boundinfo->indexes = (int *) 
> > palloc(ndatums * sizeof(int));
> > @@ -829,6 +834,18 @@ check_new_partition_bound(char *relname, Relation 
> > parent, Node *bound)
> >                             break;
> >                     }
> >  
> > +           case PARTITION_STRATEGY_HASH:
> > +                   {
> > +                           Assert(spec->strategy == 
> > PARTITION_STRATEGY_HASH);
> > +
> > +                           if (partdesc->nparts + 1 > key->partnparts)
> > +                                   ereport(ERROR,
> > +                                                   
> > (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
> > +                                   errmsg("cannot create hash partition 
> > more than %d for %s",
> > +                                                   key->partnparts, 
> > RelationGetRelationName(parent))));
> > +                           break;
> > +                   }
> > +
> >             default:
> >                     elog(ERROR, "unexpected partition strategy: %d",
> >                              (int) key->strategy);
> > @@ -916,6 +933,11 @@ get_qual_from_partbound(Relation rel, Relation parent, 
> > Node *bound)
> >                     my_qual = get_qual_for_range(key, spec);
> >                     break;
> >  
> > +           case PARTITION_STRATEGY_HASH:
> > +                   Assert(spec->strategy == PARTITION_STRATEGY_LIST);
> > +                   my_qual = get_qual_for_hash(key, spec);
> > +                   break;
> > +
> >             default:
> >                     elog(ERROR, "unexpected partition strategy: %d",
> >                              (int) key->strategy);
> > @@ -1146,6 +1168,84 @@ RelationGetPartitionDispatchInfo(Relation rel, int 
> > lockmode,
> >     return pd;
> >  }
> >  
> > +/*
> > + * convert_expr_for_hash
> > + *
> > + * Converts a expr for a hash partition's constraint.
> > + * expr is converted into 'abs(hashfunc(expr)) % npart".
> > + *
> > + * npart: number of partitions
> > + * hashfunc: OID of hash function
> > + */
> > +Expr *
> > +convert_expr_for_hash(Expr *expr, int npart, Oid hashfunc)
> > +{
> > +   FuncExpr   *func,
> > +                      *abs;
> > +   Expr       *modexpr;
> > +   Oid                     modoid;
> > +   Oid                     int4oid[1] = {INT4OID};
> > +
> > +   ParseState *pstate = make_parsestate(NULL);
> > +   Value      *val_npart = makeInteger(npart);
> > +   Node       *const_npart = (Node *) make_const(pstate, val_npart, -1);
> > +
> > +   /* hash function */
> > +   func = makeFuncExpr(hashfunc,
> > +                                           INT4OID,
> > +                                           list_make1(expr),
> > +                                           0,
> > +                                           0,
> > +                                           COERCE_EXPLICIT_CALL);
> > +
> > +   /* Abs */
> > +   abs = makeFuncExpr(LookupFuncName(list_make1(makeString("abs")), 1, 
> > int4oid, false),
> > +                                      INT4OID,
> > +                                      list_make1(func),
> > +                                      0,
> > +                                      0,
> > +                                      COERCE_EXPLICIT_CALL);
> > +
> > +   /* modulo by npart */
> > +   modoid = LookupOperName(pstate, list_make1(makeString("%")), INT4OID, 
> > INT4OID, false, -1);
> > +   modexpr = make_opclause(modoid, INT4OID, false, (Expr*)abs, 
> > (Expr*)const_npart, 0, 0);
> > +
> > +   return modexpr;
> > +}
> > +
> > +
> > +/*
> > + * get_next_hash_partition_index
> > + *
> > + * Returns the minimal index which is not used for hash partition.
> > + */
> > +int
> > +get_next_hash_partition_index(Relation parent)
> > +{
> > +   PartitionKey key = RelationGetPartitionKey(parent);
> > +   PartitionDesc partdesc = RelationGetPartitionDesc(parent);
> > +
> > +   int       i;
> > +   bool *used = palloc0(sizeof(int) * key->partnparts);
> > +
> > +   /* mark used for existing partition indexs */
> > +   for (i = 0; i < partdesc->boundinfo->ndatums; i++)
> > +   {
> > +           Datum* datum = partdesc->boundinfo->datums[i];
> > +           int idx = DatumGetInt16(datum[0]);
> > +
> > +           if (!used[idx])
> > +                   used[idx] = true;
> > +   }
> > +
> > +   /* find the minimal unused index */
> > +   for (i = 0; i < key->partnparts; i++)
> > +           if (!used[i])
> > +                   break;
> > +
> > +   return i;
> > +}
> > +
> >  /* Module-local functions */
> >  
> >  /*
> > @@ -1467,6 +1567,43 @@ get_qual_for_range(PartitionKey key, 
> > PartitionBoundSpec *spec)
> >  }
> >  
> >  /*
> > + * get_qual_for_hash
> > + *
> > + * Returns a list of expressions to use as a hash partition's constraint.
> > + */
> > +static List *
> > +get_qual_for_hash(PartitionKey key, PartitionBoundSpec *spec)
> > +{
> > +   List       *result;
> > +   Expr       *keyCol;
> > +   Expr       *expr;
> > +   Expr       *opexpr;
> > +   Oid                     operoid;
> > +   ParseState *pstate = make_parsestate(NULL);
> > +
> > +   /* Left operand */
> > +   if (key->partattrs[0] != 0)
> > +           keyCol = (Expr *) makeVar(1,
> > +                                                             
> > key->partattrs[0],
> > +                                                             
> > key->parttypid[0],
> > +                                                             
> > key->parttypmod[0],
> > +                                                             
> > key->parttypcoll[0],
> > +                                                             0);
> > +   else
> > +           keyCol = (Expr *) copyObject(linitial(key->partexprs));
> > +
> > +   expr = convert_expr_for_hash(keyCol, key->partnparts, 
> > key->parthashfunc);
> > +
> > +   /* equals the listdaums value */
> > +   operoid = LookupOperName(pstate, list_make1(makeString("=")), INT4OID, 
> > INT4OID, false, -1);
> > +   opexpr = make_opclause(operoid, BOOLOID, false, expr, 
> > linitial(spec->listdatums), 0, 0);
> > +
> > +   result = list_make1(opexpr);
> > +
> > +   return result;
> > +}
> > +
> > +/*
> >   * get_partition_operator
> >   *
> >   * Return oid of the operator of given strategy for a given partition key
> > @@ -1730,6 +1867,11 @@ get_partition_for_tuple(PartitionDispatch *pd,
> >                                                     
> > (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
> >                                             errmsg("range partition key of 
> > row contains null")));
> >             }
> > +           else if (key->strategy == PARTITION_STRATEGY_HASH)
> > +           {
> > +                   values[0] = OidFunctionCall1(key->parthashfunc, 
> > values[0]);
> > +                   values[0] = Int16GetDatum(Abs(DatumGetInt16(values[0])) 
> > % key->partnparts);
> > +           }
> >  
> >             if (partdesc->boundinfo->has_null && isnull[0])
> >                     /* Tuple maps to the null-accepting list partition */
> > @@ -1744,6 +1886,7 @@ get_partition_for_tuple(PartitionDispatch *pd,
> >                     switch (key->strategy)
> >                     {
> >                             case PARTITION_STRATEGY_LIST:
> > +                           case PARTITION_STRATEGY_HASH:
> >                                     if (cur_offset >= 0 && equal)
> >                                             cur_index = 
> > partdesc->boundinfo->indexes[cur_offset];
> >                                     else
> > @@ -1968,6 +2111,7 @@ partition_bound_cmp(PartitionKey key, 
> > PartitionBoundInfo boundinfo,
> >     switch (key->strategy)
> >     {
> >             case PARTITION_STRATEGY_LIST:
> > +           case PARTITION_STRATEGY_HASH:
> >                     cmpval = 
> > DatumGetInt32(FunctionCall2Coll(&key->partsupfunc[0],
> >                                                                             
> >                          key->partcollation[0],
> >                                                                             
> >                          bound_datums[0],
> > diff --git a/src/backend/commands/tablecmds.c 
> > b/src/backend/commands/tablecmds.c
> > index 3cea220..5a28cc0 100644
> > --- a/src/backend/commands/tablecmds.c
> > +++ b/src/backend/commands/tablecmds.c
> > @@ -41,6 +41,7 @@
> >  #include "catalog/pg_inherits_fn.h"
> >  #include "catalog/pg_namespace.h"
> >  #include "catalog/pg_opclass.h"
> > +#include "catalog/pg_proc.h"
> >  #include "catalog/pg_tablespace.h"
> >  #include "catalog/pg_trigger.h"
> >  #include "catalog/pg_type.h"
> > @@ -77,6 +78,7 @@
> >  #include "parser/parse_oper.h"
> >  #include "parser/parse_relation.h"
> >  #include "parser/parse_type.h"
> > +#include "parser/parse_func.h"
> >  #include "parser/parse_utilcmd.h"
> >  #include "parser/parser.h"
> >  #include "pgstat.h"
> > @@ -450,7 +452,7 @@ static void RangeVarCallbackForAlterRelation(const 
> > RangeVar *rv, Oid relid,
> >                                                              Oid oldrelid, 
> > void *arg);
> >  static bool is_partition_attr(Relation rel, AttrNumber attnum, bool 
> > *used_in_expr);
> >  static PartitionSpec *transformPartitionSpec(Relation rel, PartitionSpec 
> > *partspec, char *strategy);
> > -static void ComputePartitionAttrs(Relation rel, List *partParams, 
> > AttrNumber *partattrs,
> > +static void ComputePartitionAttrs(Relation rel, List *partParams, 
> > AttrNumber *partattrs, Oid *partatttypes,
> >                                       List **partexprs, Oid *partopclass, 
> > Oid *partcollation);
> >  static void CreateInheritance(Relation child_rel, Relation parent_rel);
> >  static void RemoveInheritance(Relation child_rel, Relation parent_rel);
> > @@ -799,8 +801,10 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid 
> > ownerId,
> >             AttrNumber      partattrs[PARTITION_MAX_KEYS];
> >             Oid                     partopclass[PARTITION_MAX_KEYS];
> >             Oid                     partcollation[PARTITION_MAX_KEYS];
> > +           Oid                     partatttypes[PARTITION_MAX_KEYS];
> >             List       *partexprs = NIL;
> >             List       *cmds = NIL;
> > +           Oid hashfuncOid = InvalidOid;
> >  
> >             /*
> >              * We need to transform the raw parsetrees corresponding to 
> > partition
> > @@ -811,15 +815,40 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid 
> > ownerId,
> >             stmt->partspec = transformPartitionSpec(rel, stmt->partspec,
> >                                                                             
> >                 &strategy);
> >             ComputePartitionAttrs(rel, stmt->partspec->partParams,
> > -                                                     partattrs, 
> > &partexprs, partopclass,
> > +                                                     partattrs, 
> > partatttypes, &partexprs, partopclass,
> >                                                       partcollation);
> >  
> >             partnatts = list_length(stmt->partspec->partParams);
> > +
> > +           if (strategy == PARTITION_STRATEGY_HASH)
> > +           {
> > +                   Oid funcrettype;
> > +
> > +                   if (partnatts != 1)
> > +                           ereport(ERROR,
> > +                                           
> > (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
> > +                                           errmsg("number of partition key 
> > must be 1 for hash partition")));
> > +
> > +                   hashfuncOid = LookupFuncName(stmt->partspec->hashfunc, 
> > 1, partatttypes, false);
> > +                   funcrettype = get_func_rettype(hashfuncOid);
> > +                   if (funcrettype != INT4OID)
> > +                           ereport(ERROR,
> > +                                           
> > (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
> > +                                           errmsg("hash function for 
> > partitioning must return integer")));
> > +
> > +                   if (func_volatile(hashfuncOid) != PROVOLATILE_IMMUTABLE)
> > +                           ereport(ERROR,
> > +                                           
> > (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
> > +                                           errmsg("hash function for 
> > partitioning must be marked IMMUTABLE")));
> > +
> > +           }
> > +
> >             StorePartitionKey(rel, strategy, partnatts, partattrs, 
> > partexprs,
> > -                                             partopclass, partcollation);
> > +                                             partopclass, partcollation, 
> > stmt->partspec->partnparts, hashfuncOid);
> >  
> > -           /* Force key columns to be NOT NULL when using range 
> > partitioning */
> > -           if (strategy == PARTITION_STRATEGY_RANGE)
> > +           /* Force key columns to be NOT NULL when using range or hash 
> > partitioning */
> > +           if (strategy == PARTITION_STRATEGY_RANGE ||
> > +                   strategy == PARTITION_STRATEGY_HASH)
> >             {
> >                     for (i = 0; i < partnatts; i++)
> >                     {
> > @@ -12783,18 +12812,51 @@ transformPartitionSpec(Relation rel, 
> > PartitionSpec *partspec, char *strategy)
> >     newspec->strategy = partspec->strategy;
> >     newspec->location = partspec->location;
> >     newspec->partParams = NIL;
> > +   newspec->partnparts = partspec->partnparts;
> > +   newspec->hashfunc = partspec->hashfunc;
> >  
> >     /* Parse partitioning strategy name */
> >     if (!pg_strcasecmp(partspec->strategy, "list"))
> >             *strategy = PARTITION_STRATEGY_LIST;
> >     else if (!pg_strcasecmp(partspec->strategy, "range"))
> >             *strategy = PARTITION_STRATEGY_RANGE;
> > +   else if (!pg_strcasecmp(partspec->strategy, "hash"))
> > +           *strategy = PARTITION_STRATEGY_HASH;
> >     else
> >             ereport(ERROR,
> >                             (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
> >                              errmsg("unrecognized partitioning strategy 
> > \"%s\"",
> >                                             partspec->strategy)));
> >  
> > +   if (*strategy == PARTITION_STRATEGY_HASH)
> > +   {
> > +           if (partspec->partnparts < 0)
> > +                   ereport(ERROR,
> > +                                   
> > (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
> > +                                    errmsg("number of partitions must be 
> > specified for hash partition")));
> > +           else if (partspec->partnparts == 0)
> > +                   ereport(ERROR,
> > +                                   
> > (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
> > +                                    errmsg("number of partitions must be 
> > greater than 0")));
> > +
> > +           if (list_length(partspec->hashfunc) == 0)
> > +                   ereport(ERROR,
> > +                                   
> > (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
> > +                                    errmsg("hash function must be 
> > specified for hash partition")));
> > +   }
> > +   else
> > +   {
> > +           if (partspec->partnparts >= 0)
> > +                   ereport(ERROR,
> > +                                   
> > (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
> > +                                    errmsg("number of partitions can be 
> > specified only for hash partition")));
> > +
> > +           if (list_length(partspec->hashfunc) > 0)
> > +                   ereport(ERROR,
> > +                                   
> > (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
> > +                                    errmsg("hash function can be specified 
> > only for hash partition")));
> > +   }
> > +
> >     /*
> >      * Create a dummy ParseState and insert the target relation as its sole
> >      * rangetable entry.  We need a ParseState for transformExpr.
> > @@ -12843,7 +12905,7 @@ transformPartitionSpec(Relation rel, PartitionSpec 
> > *partspec, char *strategy)
> >   * Compute per-partition-column information from a list of PartitionElem's
> >   */
> >  static void
> > -ComputePartitionAttrs(Relation rel, List *partParams, AttrNumber 
> > *partattrs,
> > +ComputePartitionAttrs(Relation rel, List *partParams, AttrNumber 
> > *partattrs, Oid *partatttypes,
> >                                       List **partexprs, Oid *partopclass, 
> > Oid *partcollation)
> >  {
> >     int                     attn;
> > @@ -13010,6 +13072,7 @@ ComputePartitionAttrs(Relation rel, List 
> > *partParams, AttrNumber *partattrs,
> >                                                                             
> >            "btree",
> >                                                                             
> >            BTREE_AM_OID);
> >  
> > +           partatttypes[attn] = atttype;
> >             attn++;
> >     }
> >  }
> > diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
> > index 05d8538..f4febc9 100644
> > --- a/src/backend/nodes/copyfuncs.c
> > +++ b/src/backend/nodes/copyfuncs.c
> > @@ -4232,6 +4232,8 @@ _copyPartitionSpec(const PartitionSpec *from)
> >  
> >     COPY_STRING_FIELD(strategy);
> >     COPY_NODE_FIELD(partParams);
> > +   COPY_SCALAR_FIELD(partnparts);
> > +   COPY_NODE_FIELD(hashfunc);
> >     COPY_LOCATION_FIELD(location);
> >  
> >     return newnode;
> > diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
> > index d595cd7..d589eac 100644
> > --- a/src/backend/nodes/equalfuncs.c
> > +++ b/src/backend/nodes/equalfuncs.c
> > @@ -2725,6 +2725,8 @@ _equalPartitionSpec(const PartitionSpec *a, const 
> > PartitionSpec *b)
> >  {
> >     COMPARE_STRING_FIELD(strategy);
> >     COMPARE_NODE_FIELD(partParams);
> > +   COMPARE_SCALAR_FIELD(partnparts);
> > +   COMPARE_NODE_FIELD(hashfunc);
> >     COMPARE_LOCATION_FIELD(location);
> >  
> >     return true;
> > diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
> > index b3802b4..d6db80e 100644
> > --- a/src/backend/nodes/outfuncs.c
> > +++ b/src/backend/nodes/outfuncs.c
> > @@ -3318,6 +3318,8 @@ _outPartitionSpec(StringInfo str, const PartitionSpec 
> > *node)
> >  
> >     WRITE_STRING_FIELD(strategy);
> >     WRITE_NODE_FIELD(partParams);
> > +   WRITE_INT_FIELD(partnparts);
> > +   WRITE_NODE_FIELD(hashfunc);
> >     WRITE_LOCATION_FIELD(location);
> >  }
> >  
> > diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
> > index e833b2e..b67140d 100644
> > --- a/src/backend/parser/gram.y
> > +++ b/src/backend/parser/gram.y
> > @@ -574,6 +574,8 @@ static Node *makeRecursiveViewSelect(char *relname, 
> > List *aliases, Node *query);
> >  %type <list>               partbound_datum_list
> >  %type <partrange_datum>    PartitionRangeDatum
> >  %type <list>               range_datum_list
> > +%type <ival>               hash_partitions
> > +%type <list>               hash_function
> >  
> >  /*
> >   * Non-keyword token types.  These are hard-wired into the "flex" lexer.
> > @@ -627,7 +629,7 @@ static Node *makeRecursiveViewSelect(char *relname, 
> > List *aliases, Node *query);
> >  
> >     GLOBAL GRANT GRANTED GREATEST GROUP_P GROUPING
> >  
> > -   HANDLER HAVING HEADER_P HOLD HOUR_P
> > +   HANDLER HASH HAVING HEADER_P HOLD HOUR_P
> >  
> >     IDENTITY_P IF_P ILIKE IMMEDIATE IMMUTABLE IMPLICIT_P IMPORT_P IN_P
> >     INCLUDING INCREMENT INDEX INDEXES INHERIT INHERITS INITIALLY INLINE_P
> > @@ -651,7 +653,7 @@ static Node *makeRecursiveViewSelect(char *relname, 
> > List *aliases, Node *query);
> >     OBJECT_P OF OFF OFFSET OIDS OLD ON ONLY OPERATOR OPTION OPTIONS OR
> >     ORDER ORDINALITY OUT_P OUTER_P OVER OVERLAPS OVERLAY OWNED OWNER
> >  
> > -   PARALLEL PARSER PARTIAL PARTITION PASSING PASSWORD PLACING PLANS POLICY
> > +   PARALLEL PARSER PARTIAL PARTITION PARTITIONS PASSING PASSWORD PLACING 
> > PLANS POLICY
> >     POSITION PRECEDING PRECISION PRESERVE PREPARE PREPARED PRIMARY
> >     PRIOR PRIVILEGES PROCEDURAL PROCEDURE PROGRAM PUBLICATION
> >  
> > @@ -2587,6 +2589,16 @@ ForValues:
> >  
> >                                     $$ = (Node *) n;
> >                             }
> > +
> > +                   /* a HASH partition */
> > +                   | /*EMPTY*/
> > +                           {
> > +                                   PartitionBoundSpec *n = 
> > makeNode(PartitionBoundSpec);
> > +
> > +                                   n->strategy = PARTITION_STRATEGY_HASH;
> > +
> > +                                   $$ = (Node *) n;
> > +                           }
> >             ;
> >  
> >  partbound_datum:
> > @@ -3666,7 +3678,7 @@ OptPartitionSpec: PartitionSpec       { $$ = $1; }
> >                     | /*EMPTY*/                     { $$ = NULL; }
> >             ;
> >  
> > -PartitionSpec: PARTITION BY part_strategy '(' part_params ')'
> > +PartitionSpec: PARTITION BY part_strategy '(' part_params ')' 
> > hash_partitions hash_function
> >                             {
> >                                     PartitionSpec *n = 
> > makeNode(PartitionSpec);
> >  
> > @@ -3674,10 +3686,21 @@ PartitionSpec: PARTITION BY part_strategy '(' 
> > part_params ')'
> >                                     n->partParams = $5;
> >                                     n->location = @1;
> >  
> > +                                   n->partnparts = $7;
> > +                                   n->hashfunc = $8;
> > +
> >                                     $$ = n;
> >                             }
> >             ;
> >  
> > +hash_partitions: PARTITIONS Iconst { $$ = $2; }
> > +                                   | /*EMPTY*/   { $$ = -1; }
> > +           ;
> > +
> > +hash_function: USING handler_name { $$ = $2; }
> > +                                   | /*EMPTY*/ { $$ = NULL; }
> > +           ;
> > +
> >  part_strategy:     IDENT                                   { $$ = $1; }
> >                             | unreserved_keyword    { $$ = pstrdup($1); }
> >             ;
> > @@ -14377,6 +14400,7 @@ unreserved_keyword:
> >                     | GLOBAL
> >                     | GRANTED
> >                     | HANDLER
> > +                   | HASH
> >                     | HEADER_P
> >                     | HOLD
> >                     | HOUR_P
> > @@ -14448,6 +14472,7 @@ unreserved_keyword:
> >                     | PARSER
> >                     | PARTIAL
> >                     | PARTITION
> > +                   | PARTITIONS
> >                     | PASSING
> >                     | PASSWORD
> >                     | PLANS
> > diff --git a/src/backend/parser/parse_utilcmd.c 
> > b/src/backend/parser/parse_utilcmd.c
> > index ff2bab6..8e1be31 100644
> > --- a/src/backend/parser/parse_utilcmd.c
> > +++ b/src/backend/parser/parse_utilcmd.c
> > @@ -40,6 +40,7 @@
> >  #include "catalog/pg_opclass.h"
> >  #include "catalog/pg_operator.h"
> >  #include "catalog/pg_type.h"
> > +#include "catalog/partition.h"
> >  #include "commands/comment.h"
> >  #include "commands/defrem.h"
> >  #include "commands/tablecmds.h"
> > @@ -3252,6 +3253,24 @@ transformPartitionBound(ParseState *pstate, Relation 
> > parent, Node *bound)
> >                     ++i;
> >             }
> >     }
> > +   else if (strategy == PARTITION_STRATEGY_HASH)
> > +   {
> > +           Value    *conval;
> > +           Node     *value;
> > +           int               index;
> > +
> > +           if (spec->strategy != PARTITION_STRATEGY_HASH)
> > +                   ereport(ERROR,
> > +                                   
> > (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
> > +                            errmsg("invalid bound specification for a hash 
> > partition")));
> > +
> > +           index = get_next_hash_partition_index(parent);
> > +
> > +           /* store the partition index as a listdatums value */
> > +           conval = makeInteger(index);
> > +           value = (Node *) make_const(pstate, conval, -1);
> > +           result_spec->listdatums = list_make1(value);
> > +   }
> >     else
> >             elog(ERROR, "unexpected partition strategy: %d", (int) 
> > strategy);
> >  
> > diff --git a/src/backend/utils/adt/ruleutils.c 
> > b/src/backend/utils/adt/ruleutils.c
> > index b27b77d..fab6eea 100644
> > --- a/src/backend/utils/adt/ruleutils.c
> > +++ b/src/backend/utils/adt/ruleutils.c
> > @@ -1423,7 +1423,7 @@ pg_get_indexdef_worker(Oid indexrelid, int colno,
> >   *
> >   * Returns the partition key specification, ie, the following:
> >   *
> > - * PARTITION BY { RANGE | LIST } (column opt_collation opt_opclass [, ...])
> > + * PARTITION BY { RANGE | LIST | HASH } (column opt_collation opt_opclass 
> > [, ...])
> >   */
> >  Datum
> >  pg_get_partkeydef(PG_FUNCTION_ARGS)
> > @@ -1513,6 +1513,9 @@ pg_get_partkeydef_worker(Oid relid, int prettyFlags)
> >             case PARTITION_STRATEGY_RANGE:
> >                     appendStringInfo(&buf, "RANGE");
> >                     break;
> > +           case PARTITION_STRATEGY_HASH:
> > +                   appendStringInfo(&buf, "HASH");
> > +                   break;
> >             default:
> >                     elog(ERROR, "unexpected partition strategy: %d",
> >                              (int) form->partstrat);
> > @@ -8520,6 +8523,9 @@ get_rule_expr(Node *node, deparse_context *context,
> >                                             appendStringInfoString(buf, 
> > ")");
> >                                             break;
> >  
> > +                                   case PARTITION_STRATEGY_HASH:
> > +                                           break;
> > +
> >                                     default:
> >                                             elog(ERROR, "unrecognized 
> > partition strategy: %d",
> >                                                      (int) spec->strategy);
> > diff --git a/src/backend/utils/cache/relcache.c 
> > b/src/backend/utils/cache/relcache.c
> > index 9001e20..829e4d2 100644
> > --- a/src/backend/utils/cache/relcache.c
> > +++ b/src/backend/utils/cache/relcache.c
> > @@ -855,6 +855,9 @@ RelationBuildPartitionKey(Relation relation)
> >     key->strategy = form->partstrat;
> >     key->partnatts = form->partnatts;
> >  
> > +   key->partnparts = form->partnparts;
> > +   key->parthashfunc = form->parthashfunc;
> > +
> >     /*
> >      * We can rely on the first variable-length attribute being mapped to 
> > the
> >      * relevant field of the catalog's C struct, because all previous
> > @@ -999,6 +1002,9 @@ copy_partition_key(PartitionKey fromkey)
> >     newkey->strategy = fromkey->strategy;
> >     newkey->partnatts = n = fromkey->partnatts;
> >  
> > +   newkey->partnparts = fromkey->partnparts;
> > +   newkey->parthashfunc = fromkey->parthashfunc;
> > +
> >     newkey->partattrs = (AttrNumber *) palloc(n * sizeof(AttrNumber));
> >     memcpy(newkey->partattrs, fromkey->partattrs, n * sizeof(AttrNumber));
> >  
> > diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
> > index 1187797..367e2f8 100644
> > --- a/src/include/catalog/heap.h
> > +++ b/src/include/catalog/heap.h
> > @@ -141,7 +141,7 @@ extern void StorePartitionKey(Relation rel,
> >                               AttrNumber *partattrs,
> >                               List *partexprs,
> >                               Oid *partopclass,
> > -                             Oid *partcollation);
> > +                             Oid *partcollation, int16 partnparts, Oid 
> > hashfunc);
> >  extern void RemovePartitionKeyByRelId(Oid relid);
> >  extern void StorePartitionBound(Relation rel, Relation parent, Node 
> > *bound);
> >  
> > diff --git a/src/include/catalog/partition.h 
> > b/src/include/catalog/partition.h
> > index b195d1a..80f4b0e 100644
> > --- a/src/include/catalog/partition.h
> > +++ b/src/include/catalog/partition.h
> > @@ -89,4 +89,6 @@ extern int get_partition_for_tuple(PartitionDispatch *pd,
> >                                             TupleTableSlot *slot,
> >                                             EState *estate,
> >                                             Oid *failed_at);
> > +extern Expr *convert_expr_for_hash(Expr *expr, int npart, Oid hashfunc);
> > +extern int get_next_hash_partition_index(Relation parent);
> >  #endif   /* PARTITION_H */
> > diff --git a/src/include/catalog/pg_partitioned_table.h 
> > b/src/include/catalog/pg_partitioned_table.h
> > index bdff36a..69e509c 100644
> > --- a/src/include/catalog/pg_partitioned_table.h
> > +++ b/src/include/catalog/pg_partitioned_table.h
> > @@ -33,6 +33,9 @@ CATALOG(pg_partitioned_table,3350) BKI_WITHOUT_OIDS
> >     char            partstrat;              /* partitioning strategy */
> >     int16           partnatts;              /* number of partition key 
> > columns */
> >  
> > +   int16           partnparts;
> > +   Oid                     parthashfunc;
> > +
> >     /*
> >      * variable-length fields start here, but we allow direct access to
> >      * partattrs via the C struct.  That's because the first variable-length
> > @@ -49,6 +52,8 @@ CATALOG(pg_partitioned_table,3350) BKI_WITHOUT_OIDS
> >     pg_node_tree partexprs;         /* list of expressions in the partition 
> > key;
> >                                                              * one item for 
> > each zero entry in partattrs[] */
> >  #endif
> > +
> > +
> >  } FormData_pg_partitioned_table;
> >  
> >  /* ----------------
> > @@ -62,13 +67,15 @@ typedef FormData_pg_partitioned_table 
> > *Form_pg_partitioned_table;
> >   *         compiler constants for pg_partitioned_table
> >   * ----------------
> >   */
> > -#define Natts_pg_partitioned_table                         7
> > +#define Natts_pg_partitioned_table                         9
> >  #define Anum_pg_partitioned_table_partrelid                1
> >  #define Anum_pg_partitioned_table_partstrat                2
> >  #define Anum_pg_partitioned_table_partnatts                3
> > -#define Anum_pg_partitioned_table_partattrs                4
> > -#define Anum_pg_partitioned_table_partclass                5
> > -#define Anum_pg_partitioned_table_partcollation 6
> > -#define Anum_pg_partitioned_table_partexprs                7
> > +#define Anum_pg_partitioned_table_partnparts       4
> > +#define Anum_pg_partitioned_table_parthashfunc     5
> > +#define Anum_pg_partitioned_table_partattrs                6
> > +#define Anum_pg_partitioned_table_partclass                7
> > +#define Anum_pg_partitioned_table_partcollation 8
> > +#define Anum_pg_partitioned_table_partexprs                9
> >  
> >  #endif   /* PG_PARTITIONED_TABLE_H */
> > diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
> > index 5afc3eb..1c3474f 100644
> > --- a/src/include/nodes/parsenodes.h
> > +++ b/src/include/nodes/parsenodes.h
> > @@ -730,11 +730,14 @@ typedef struct PartitionSpec
> >     NodeTag         type;
> >     char       *strategy;           /* partitioning strategy ('list' or 
> > 'range') */
> >     List       *partParams;         /* List of PartitionElems */
> > +   int                 partnparts;
> > +   List       *hashfunc;
> >     int                     location;               /* token location, or 
> > -1 if unknown */
> >  } PartitionSpec;
> >  
> >  #define PARTITION_STRATEGY_LIST            'l'
> >  #define PARTITION_STRATEGY_RANGE   'r'
> > +#define PARTITION_STRATEGY_HASH            'h'
> >  
> >  /*
> >   * PartitionBoundSpec - a partition bound specification
> > diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
> > index 985d650..0597939 100644
> > --- a/src/include/parser/kwlist.h
> > +++ b/src/include/parser/kwlist.h
> > @@ -180,6 +180,7 @@ PG_KEYWORD("greatest", GREATEST, COL_NAME_KEYWORD)
> >  PG_KEYWORD("group", GROUP_P, RESERVED_KEYWORD)
> >  PG_KEYWORD("grouping", GROUPING, COL_NAME_KEYWORD)
> >  PG_KEYWORD("handler", HANDLER, UNRESERVED_KEYWORD)
> > +PG_KEYWORD("hash", HASH, UNRESERVED_KEYWORD)
> >  PG_KEYWORD("having", HAVING, RESERVED_KEYWORD)
> >  PG_KEYWORD("header", HEADER_P, UNRESERVED_KEYWORD)
> >  PG_KEYWORD("hold", HOLD, UNRESERVED_KEYWORD)
> > @@ -291,6 +292,7 @@ PG_KEYWORD("parallel", PARALLEL, UNRESERVED_KEYWORD)
> >  PG_KEYWORD("parser", PARSER, UNRESERVED_KEYWORD)
> >  PG_KEYWORD("partial", PARTIAL, UNRESERVED_KEYWORD)
> >  PG_KEYWORD("partition", PARTITION, UNRESERVED_KEYWORD)
> > +PG_KEYWORD("partitions", PARTITIONS, UNRESERVED_KEYWORD)
> >  PG_KEYWORD("passing", PASSING, UNRESERVED_KEYWORD)
> >  PG_KEYWORD("password", PASSWORD, UNRESERVED_KEYWORD)
> >  PG_KEYWORD("placing", PLACING, RESERVED_KEYWORD)
> > diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
> > index a617a7c..660adfb 100644
> > --- a/src/include/utils/rel.h
> > +++ b/src/include/utils/rel.h
> > @@ -62,6 +62,9 @@ typedef struct PartitionKeyData
> >     Oid                *partopcintype;      /* OIDs of opclass declared 
> > input data types */
> >     FmgrInfo   *partsupfunc;        /* lookup info for support funcs */
> >  
> > +   int16       partnparts;         /* number of hash partitions */
> > +   Oid                 parthashfunc;       /* OID of hash function */
> > +
> >     /* Partitioning collation per attribute */
> >     Oid                *partcollation;
> >  
> 
> > 
> > -- 
> > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
> > To make changes to your subscription:
> > http://www.postgresql.org/mailpref/pgsql-hackers
> 
> 
> -- 
> Best regards,
> Aleksander Alekseev


-- 
Yugo Nagata <nag...@sraoss.co.jp>


-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers

Reply via email to