database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-05 07:21:24 +03:00
Code Activity

Reorganize partitioning code

Browse Source 
There's been a massive addition of partitioning code in PostgreSQL 11,
with little oversight on its placement, resulting in a
catalog/partition.c with poorly defined boundaries and responsibilities.
This commit tries to set a couple of distinct modules to separate things
a little bit.  There are no code changes here, only code movement.

There are three new files:
  src/backend/utils/cache/partcache.c
  src/include/partitioning/partdefs.h
  src/include/utils/partcache.h

The previous arrangement of #including catalog/partition.h almost
everywhere is no more.

Authors: Amit Langote and Álvaro Herrera
Discussion: https://postgr.es/m/98e8d509-790a-128c-be7f-e48a5b2d8d97@lab.ntt.co.jp
	https://postgr.es/m/11aa0c50-316b-18bb-722d-c23814f39059@lab.ntt.co.jp
	https://postgr.es/m/143ed9a4-6038-76d4-9a55-502035815e68@lab.ntt.co.jp
	https://postgr.es/m/20180413193503.nynq7bnmgh6vs5vm@alvherre.pgsql
This commit is contained in:
Alvaro Herrera
2018-04-14 21:12:14 -03:00
parent b39fd897e0
commit da6f3e45dd
32 changed files with 3587 additions and 3479 deletions
Download Patch File Download Diff File Expand all files Collapse all files

967
src/backend/utils/cache/partcache.c vendored Normal file
View File

@ -0,0 +1,967 @@
/*-------------------------------------------------------------------------
*
* partcache.c
* Support routines for manipulating partition information cached in
* relcache
*
* Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/utils/cache/partcache.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/hash.h"
#include "access/heapam.h"
#include "access/htup_details.h"
#include "access/nbtree.h"
#include "catalog/partition.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_partitioned_table.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/planner.h"
#include "partitioning/partbounds.h"
#include "utils/builtins.h"
#include "utils/datum.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/partcache.h"
#include "utils/rel.h"
#include "utils/syscache.h"
static List *generate_partition_qual(Relation rel);
static int32 qsort_partition_hbound_cmp(const void *a, const void *b);
static int32 qsort_partition_list_value_cmp(const void *a, const void *b,
void *arg);
static int32 qsort_partition_rbound_cmp(const void *a, const void *b,
void *arg);
/*
* RelationBuildPartitionKey
* Build and attach to relcache partition key data of relation
*
* Partitioning key data is a complex structure; to avoid complicated logic to
* free individual elements whenever the relcache entry is flushed, we give it
* its own memory context, child of CacheMemoryContext, which can easily be
* deleted on its own. To avoid leaking memory in that context in case of an
* error partway through this function, the context is initially created as a
* child of CurTransactionContext and only re-parented to CacheMemoryContext
* at the end, when no further errors are possible. Also, we don't make this
* context the current context except in very brief code sections, out of fear
* that some of our callees allocate memory on their own which would be leaked
* permanently.
*/
void
RelationBuildPartitionKey(Relation relation)
{
Form_pg_partitioned_table form;
HeapTuple tuple;
bool isnull;
int i;
PartitionKey key;
AttrNumber *attrs;
oidvector *opclass;
oidvector *collation;
ListCell *partexprs_item;
Datum datum;
MemoryContext partkeycxt,
oldcxt;
int16 procnum;
tuple = SearchSysCache1(PARTRELID,
ObjectIdGetDatum(RelationGetRelid(relation)));
/*
* The following happens when we have created our pg_class entry but not
* the pg_partitioned_table entry yet.
*/
if (!HeapTupleIsValid(tuple))
return;
partkeycxt = AllocSetContextCreate(CurTransactionContext,
"partition key",
ALLOCSET_SMALL_SIZES);
MemoryContextCopyAndSetIdentifier(partkeycxt,
RelationGetRelationName(relation));
key = (PartitionKey) MemoryContextAllocZero(partkeycxt,
sizeof(PartitionKeyData));
/* Fixed-length attributes */
form = (Form_pg_partitioned_table) GETSTRUCT(tuple);
key->strategy = form->partstrat;
key->partnatts = form->partnatts;
/*
* We can rely on the first variable-length attribute being mapped to the
* relevant field of the catalog's C struct, because all previous
* attributes are non-nullable and fixed-length.
*/
attrs = form->partattrs.values;
/* But use the hard way to retrieve further variable-length attributes */
/* Operator class */
datum = SysCacheGetAttr(PARTRELID, tuple,
Anum_pg_partitioned_table_partclass, &isnull);
Assert(!isnull);
opclass = (oidvector *) DatumGetPointer(datum);
/* Collation */
datum = SysCacheGetAttr(PARTRELID, tuple,
Anum_pg_partitioned_table_partcollation, &isnull);
Assert(!isnull);
collation = (oidvector *) DatumGetPointer(datum);
/* Expressions */
datum = SysCacheGetAttr(PARTRELID, tuple,
Anum_pg_partitioned_table_partexprs, &isnull);
if (!isnull)
{
char *exprString;
Node *expr;
exprString = TextDatumGetCString(datum);
expr = stringToNode(exprString);
pfree(exprString);
/*
* Run the expressions through const-simplification since the planner
* will be comparing them to similarly-processed qual clause operands,
* and may fail to detect valid matches without this step; fix
* opfuncids while at it. We don't need to bother with
* canonicalize_qual() though, because partition expressions should be
* in canonical form already (ie, no need for OR-merging or constant
* elimination).
*/
expr = eval_const_expressions(NULL, expr);
fix_opfuncids(expr);
oldcxt = MemoryContextSwitchTo(partkeycxt);
key->partexprs = (List *) copyObject(expr);
MemoryContextSwitchTo(oldcxt);
}
oldcxt = MemoryContextSwitchTo(partkeycxt);
key->partattrs = (AttrNumber *) palloc0(key->partnatts * sizeof(AttrNumber));
key->partopfamily = (Oid *) palloc0(key->partnatts * sizeof(Oid));
key->partopcintype = (Oid *) palloc0(key->partnatts * sizeof(Oid));
key->partsupfunc = (FmgrInfo *) palloc0(key->partnatts * sizeof(FmgrInfo));
key->partcollation = (Oid *) palloc0(key->partnatts * sizeof(Oid));
/* Gather type and collation info as well */
key->parttypid = (Oid *) palloc0(key->partnatts * sizeof(Oid));
key->parttypmod = (int32 *) palloc0(key->partnatts * sizeof(int32));
key->parttyplen = (int16 *) palloc0(key->partnatts * sizeof(int16));
key->parttypbyval = (bool *) palloc0(key->partnatts * sizeof(bool));
key->parttypalign = (char *) palloc0(key->partnatts * sizeof(char));
key->parttypcoll = (Oid *) palloc0(key->partnatts * sizeof(Oid));
MemoryContextSwitchTo(oldcxt);
/* determine support function number to search for */
procnum = (key->strategy == PARTITION_STRATEGY_HASH) ?
HASHEXTENDED_PROC : BTORDER_PROC;
/* Copy partattrs and fill other per-attribute info */
memcpy(key->partattrs, attrs, key->partnatts * sizeof(int16));
partexprs_item = list_head(key->partexprs);
for (i = 0; i < key->partnatts; i++)
{
AttrNumber attno = key->partattrs[i];
HeapTuple opclasstup;
Form_pg_opclass opclassform;
Oid funcid;
/* Collect opfamily information */
opclasstup = SearchSysCache1(CLAOID,
ObjectIdGetDatum(opclass->values[i]));
if (!HeapTupleIsValid(opclasstup))
elog(ERROR, "cache lookup failed for opclass %u", opclass->values[i]);
opclassform = (Form_pg_opclass) GETSTRUCT(opclasstup);
key->partopfamily[i] = opclassform->opcfamily;
key->partopcintype[i] = opclassform->opcintype;
/* Get a support function for the specified opfamily and datatypes */
funcid = get_opfamily_proc(opclassform->opcfamily,
opclassform->opcintype,
opclassform->opcintype,
procnum);
if (!OidIsValid(funcid))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("operator class \"%s\" of access method %s is missing support function %d for type %s",
NameStr(opclassform->opcname),
(key->strategy == PARTITION_STRATEGY_HASH) ?
"hash" : "btree",
procnum,
format_type_be(opclassform->opcintype))));
fmgr_info_cxt(funcid, &key->partsupfunc[i], partkeycxt);
/* Collation */
key->partcollation[i] = collation->values[i];
/* Collect type information */
if (attno != 0)
{
Form_pg_attribute att = TupleDescAttr(relation->rd_att, attno - 1);
key->parttypid[i] = att->atttypid;
key->parttypmod[i] = att->atttypmod;
key->parttypcoll[i] = att->attcollation;
}
else
{
if (partexprs_item == NULL)
elog(ERROR, "wrong number of partition key expressions");
key->parttypid[i] = exprType(lfirst(partexprs_item));
key->parttypmod[i] = exprTypmod(lfirst(partexprs_item));
key->parttypcoll[i] = exprCollation(lfirst(partexprs_item));
partexprs_item = lnext(partexprs_item);
}
get_typlenbyvalalign(key->parttypid[i],
&key->parttyplen[i],
&key->parttypbyval[i],
&key->parttypalign[i]);
ReleaseSysCache(opclasstup);
}
ReleaseSysCache(tuple);
/*
* Success --- reparent our context and make the relcache point to the
* newly constructed key
*/
MemoryContextSetParent(partkeycxt, CacheMemoryContext);
relation->rd_partkeycxt = partkeycxt;
relation->rd_partkey = key;
}
/*
* RelationBuildPartitionDesc
* Form rel's partition descriptor
*
* Not flushed from the cache by RelationClearRelation() unless changed because
* of addition or removal of partition.
*/
void
RelationBuildPartitionDesc(Relation rel)
{
List *inhoids,
*partoids;
Oid *oids = NULL;
List *boundspecs = NIL;
ListCell *cell;
int i,
nparts;
PartitionKey key = RelationGetPartitionKey(rel);
PartitionDesc result;
MemoryContext oldcxt;
int ndatums = 0;
int default_index = -1;
/* Hash partitioning specific */
PartitionHashBound **hbounds = NULL;
/* List partitioning specific */
PartitionListValue **all_values = NULL;
int null_index = -1;
/* Range partitioning specific */
PartitionRangeBound **rbounds = NULL;
/* Get partition oids from pg_inherits */
inhoids = find_inheritance_children(RelationGetRelid(rel), NoLock);
/* Collect bound spec nodes in a list */
i = 0;
partoids = NIL;
foreach(cell, inhoids)
{
Oid inhrelid = lfirst_oid(cell);
HeapTuple tuple;
Datum datum;
bool isnull;
Node *boundspec;
tuple = SearchSysCache1(RELOID, inhrelid);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", inhrelid);
/*
* It is possible that the pg_class tuple of a partition has not been
* updated yet to set its relpartbound field. The only case where
* this happens is when we open the parent relation to check using its
* partition descriptor that a new partition's bound does not overlap
* some existing partition.
*/
if (!((Form_pg_class) GETSTRUCT(tuple))->relispartition)
{
ReleaseSysCache(tuple);
continue;
}
datum = SysCacheGetAttr(RELOID, tuple,
Anum_pg_class_relpartbound,
&isnull);
Assert(!isnull);
boundspec = (Node *) stringToNode(TextDatumGetCString(datum));
/*
* Sanity check: If the PartitionBoundSpec says this is the default
* partition, its OID should correspond to whatever's stored in
* pg_partitioned_table.partdefid; if not, the catalog is corrupt.
*/
if (castNode(PartitionBoundSpec, boundspec)->is_default)
{
Oid partdefid;
partdefid = get_default_partition_oid(RelationGetRelid(rel));
if (partdefid != inhrelid)
elog(ERROR, "expected partdefid %u, but got %u",
inhrelid, partdefid);
}
boundspecs = lappend(boundspecs, boundspec);
partoids = lappend_oid(partoids, inhrelid);
ReleaseSysCache(tuple);
}
nparts = list_length(partoids);
if (nparts > 0)
{
oids = (Oid *) palloc(nparts * sizeof(Oid));
i = 0;
foreach(cell, partoids)
oids[i++] = lfirst_oid(cell);
/* Convert from node to the internal representation */
if (key->strategy == PARTITION_STRATEGY_HASH)
{
ndatums = nparts;
hbounds = (PartitionHashBound **)
palloc(nparts * sizeof(PartitionHashBound *));
i = 0;
foreach(cell, boundspecs)
{
PartitionBoundSpec *spec = castNode(PartitionBoundSpec,
lfirst(cell));
if (spec->strategy != PARTITION_STRATEGY_HASH)
elog(ERROR, "invalid strategy in partition bound spec");
hbounds[i] = (PartitionHashBound *)
palloc(sizeof(PartitionHashBound));
hbounds[i]->modulus = spec->modulus;
hbounds[i]->remainder = spec->remainder;
hbounds[i]->index = i;
i++;
}
/* Sort all the bounds in ascending order */
qsort(hbounds, nparts, sizeof(PartitionHashBound *),
qsort_partition_hbound_cmp);
}
else if (key->strategy == PARTITION_STRATEGY_LIST)
{
List *non_null_values = NIL;
/*
* Create a unified list of non-null values across all partitions.
*/
i = 0;
null_index = -1;
foreach(cell, boundspecs)
{
PartitionBoundSpec *spec = castNode(PartitionBoundSpec,
lfirst(cell));
ListCell *c;
if (spec->strategy != PARTITION_STRATEGY_LIST)
elog(ERROR, "invalid strategy in partition bound spec");
/*
* Note the index of the partition bound spec for the default
* partition. There's no datum to add to the list of non-null
* datums for this partition.
*/
if (spec->is_default)
{
default_index = i;
i++;
continue;
}
foreach(c, spec->listdatums)
{
Const *val = castNode(Const, lfirst(c));
PartitionListValue *list_value = NULL;
if (!val->constisnull)
{
list_value = (PartitionListValue *)
palloc0(sizeof(PartitionListValue));
list_value->index = i;
list_value->value = val->constvalue;
}
else
{
/*
* Never put a null into the values array, flag
* instead for the code further down below where we
* construct the actual relcache struct.
*/
if (null_index != -1)
elog(ERROR, "found null more than once");
null_index = i;
}
if (list_value)
non_null_values = lappend(non_null_values,
list_value);
}
i++;
}
ndatums = list_length(non_null_values);
/*
* Collect all list values in one array. Alongside the value, we
* also save the index of partition the value comes from.
*/
all_values = (PartitionListValue **) palloc(ndatums *
sizeof(PartitionListValue *));
i = 0;
foreach(cell, non_null_values)
{
PartitionListValue *src = lfirst(cell);
all_values[i] = (PartitionListValue *)
palloc(sizeof(PartitionListValue));
all_values[i]->value = src->value;
all_values[i]->index = src->index;
i++;
}
qsort_arg(all_values, ndatums, sizeof(PartitionListValue *),
qsort_partition_list_value_cmp, (void *) key);
}
else if (key->strategy == PARTITION_STRATEGY_RANGE)
{
int k;
PartitionRangeBound **all_bounds,
*prev;
all_bounds = (PartitionRangeBound **) palloc0(2 * nparts *
sizeof(PartitionRangeBound *));
/*
* Create a unified list of range bounds across all the
* partitions.
*/
i = ndatums = 0;
foreach(cell, boundspecs)
{
PartitionBoundSpec *spec = castNode(PartitionBoundSpec,
lfirst(cell));
PartitionRangeBound *lower,
*upper;
if (spec->strategy != PARTITION_STRATEGY_RANGE)
elog(ERROR, "invalid strategy in partition bound spec");
/*
* Note the index of the partition bound spec for the default
* partition. There's no datum to add to the allbounds array
* for this partition.
*/
if (spec->is_default)
{
default_index = i++;
continue;
}
lower = make_one_range_bound(key, i, spec->lowerdatums,
true);
upper = make_one_range_bound(key, i, spec->upperdatums,
false);
all_bounds[ndatums++] = lower;
all_bounds[ndatums++] = upper;
i++;
}
Assert(ndatums == nparts * 2 ||
(default_index != -1 && ndatums == (nparts - 1) * 2));
/* Sort all the bounds in ascending order */
qsort_arg(all_bounds, ndatums,
sizeof(PartitionRangeBound *),
qsort_partition_rbound_cmp,
(void *) key);
/* Save distinct bounds from all_bounds into rbounds. */
rbounds = (PartitionRangeBound **)
palloc(ndatums * sizeof(PartitionRangeBound *));
k = 0;
prev = NULL;
for (i = 0; i < ndatums; i++)
{
PartitionRangeBound *cur = all_bounds[i];
bool is_distinct = false;
int j;
/* Is the current bound distinct from the previous one? */
for (j = 0; j < key->partnatts; j++)
{
Datum cmpval;
if (prev == NULL || cur->kind[j] != prev->kind[j])
{
is_distinct = true;
break;
}
/*
* If the bounds are both MINVALUE or MAXVALUE, stop now
* and treat them as equal, since any values after this
* point must be ignored.
*/
if (cur->kind[j] != PARTITION_RANGE_DATUM_VALUE)
break;
cmpval = FunctionCall2Coll(&key->partsupfunc[j],
key->partcollation[j],
cur->datums[j],
prev->datums[j]);
if (DatumGetInt32(cmpval) != 0)
{
is_distinct = true;
break;
}
}
/*
* Only if the bound is distinct save it into a temporary
* array i.e. rbounds which is later copied into boundinfo
* datums array.
*/
if (is_distinct)
rbounds[k++] = all_bounds[i];
prev = cur;
}
/* Update ndatums to hold the count of distinct datums. */
ndatums = k;
}
else
elog(ERROR, "unexpected partition strategy: %d",
(int) key->strategy);
}
/* Now build the actual relcache partition descriptor */
rel->rd_pdcxt = AllocSetContextCreate(CacheMemoryContext,
"partition descriptor",
ALLOCSET_DEFAULT_SIZES);
MemoryContextCopyAndSetIdentifier(rel->rd_pdcxt, RelationGetRelationName(rel));
oldcxt = MemoryContextSwitchTo(rel->rd_pdcxt);
result = (PartitionDescData *) palloc0(sizeof(PartitionDescData));
result->nparts = nparts;
if (nparts > 0)
{
PartitionBoundInfo boundinfo;
int *mapping;
int next_index = 0;
result->oids = (Oid *) palloc0(nparts * sizeof(Oid));
boundinfo = (PartitionBoundInfoData *)
palloc0(sizeof(PartitionBoundInfoData));
boundinfo->strategy = key->strategy;
boundinfo->default_index = -1;
boundinfo->ndatums = ndatums;
boundinfo->null_index = -1;
boundinfo->datums = (Datum **) palloc0(ndatums * sizeof(Datum *));
/* Initialize mapping array with invalid values */
mapping = (int *) palloc(sizeof(int) * nparts);
for (i = 0; i < nparts; i++)
mapping[i] = -1;
switch (key->strategy)
{
case PARTITION_STRATEGY_HASH:
{
/* Modulus are stored in ascending order */
int greatest_modulus = hbounds[ndatums - 1]->modulus;
boundinfo->indexes = (int *) palloc(greatest_modulus *
sizeof(int));
for (i = 0; i < greatest_modulus; i++)
boundinfo->indexes[i] = -1;
for (i = 0; i < nparts; i++)
{
int modulus = hbounds[i]->modulus;
int remainder = hbounds[i]->remainder;
boundinfo->datums[i] = (Datum *) palloc(2 *
sizeof(Datum));
boundinfo->datums[i][0] = Int32GetDatum(modulus);
boundinfo->datums[i][1] = Int32GetDatum(remainder);
while (remainder < greatest_modulus)
{
/* overlap? */
Assert(boundinfo->indexes[remainder] == -1);
boundinfo->indexes[remainder] = i;
remainder += modulus;
}
mapping[hbounds[i]->index] = i;
pfree(hbounds[i]);
}
pfree(hbounds);
break;
}
case PARTITION_STRATEGY_LIST:
{
boundinfo->indexes = (int *) palloc(ndatums * sizeof(int));
/*
* Copy values. Indexes of individual values are mapped
* to canonical values so that they match for any two list
* partitioned tables with same number of partitions and
* same lists per partition. One way to canonicalize is
* to assign the index in all_values[] of the smallest
* value of each partition, as the index of all of the
* partition's values.
*/
for (i = 0; i < ndatums; i++)
{
boundinfo->datums[i] = (Datum *) palloc(sizeof(Datum));
boundinfo->datums[i][0] = datumCopy(all_values[i]->value,
key->parttypbyval[0],
key->parttyplen[0]);
/* If the old index has no mapping, assign one */
if (mapping[all_values[i]->index] == -1)
mapping[all_values[i]->index] = next_index++;
boundinfo->indexes[i] = mapping[all_values[i]->index];
}
/*
* If null-accepting partition has no mapped index yet,
* assign one. This could happen if such partition
* accepts only null and hence not covered in the above
* loop which only handled non-null values.
*/
if (null_index != -1)
{
Assert(null_index >= 0);
if (mapping[null_index] == -1)
mapping[null_index] = next_index++;
boundinfo->null_index = mapping[null_index];
}
/* Assign mapped index for the default partition. */
if (default_index != -1)
{
/*
* The default partition accepts any value not
* specified in the lists of other partitions, hence
* it should not get mapped index while assigning
* those for non-null datums.
*/
Assert(default_index >= 0 &&
mapping[default_index] == -1);
mapping[default_index] = next_index++;
boundinfo->default_index = mapping[default_index];
}
/* All partition must now have a valid mapping */
Assert(next_index == nparts);
break;
}
case PARTITION_STRATEGY_RANGE:
{
boundinfo->kind = (PartitionRangeDatumKind **)
palloc(ndatums *
sizeof(PartitionRangeDatumKind *));
boundinfo->indexes = (int *) palloc((ndatums + 1) *
sizeof(int));
for (i = 0; i < ndatums; i++)
{
int j;
boundinfo->datums[i] = (Datum *) palloc(key->partnatts *
sizeof(Datum));
boundinfo->kind[i] = (PartitionRangeDatumKind *)
palloc(key->partnatts *
sizeof(PartitionRangeDatumKind));
for (j = 0; j < key->partnatts; j++)
{
if (rbounds[i]->kind[j] == PARTITION_RANGE_DATUM_VALUE)
boundinfo->datums[i][j] =
datumCopy(rbounds[i]->datums[j],
key->parttypbyval[j],
key->parttyplen[j]);
boundinfo->kind[i][j] = rbounds[i]->kind[j];
}
/*
* There is no mapping for invalid indexes.
*
* Any lower bounds in the rbounds array have invalid
* indexes assigned, because the values between the
* previous bound (if there is one) and this (lower)
* bound are not part of the range of any existing
* partition.
*/
if (rbounds[i]->lower)
boundinfo->indexes[i] = -1;
else
{
int orig_index = rbounds[i]->index;
/* If the old index has no mapping, assign one */
if (mapping[orig_index] == -1)
mapping[orig_index] = next_index++;
boundinfo->indexes[i] = mapping[orig_index];
}
}
/* Assign mapped index for the default partition. */
if (default_index != -1)
{
Assert(default_index >= 0 && mapping[default_index] == -1);
mapping[default_index] = next_index++;
boundinfo->default_index = mapping[default_index];
}
boundinfo->indexes[i] = -1;
break;
}
default:
elog(ERROR, "unexpected partition strategy: %d",
(int) key->strategy);
}
result->boundinfo = boundinfo;
/*
* Now assign OIDs from the original array into mapped indexes of the
* result array. Order of OIDs in the former is defined by the
* catalog scan that retrieved them, whereas that in the latter is
* defined by canonicalized representation of the partition bounds.
*/
for (i = 0; i < nparts; i++)
result->oids[mapping[i]] = oids[i];
pfree(mapping);
}
MemoryContextSwitchTo(oldcxt);
rel->rd_partdesc = result;
}
/*
* RelationGetPartitionQual
*
* Returns a list of partition quals
*/
List *
RelationGetPartitionQual(Relation rel)
{
/* Quick exit */
if (!rel->rd_rel->relispartition)
return NIL;
return generate_partition_qual(rel);
}
/*
* get_partition_qual_relid
*
* Returns an expression tree describing the passed-in relation's partition
* constraint. If there is no partition constraint returns NULL; this can
* happen if the default partition is the only partition.
*/
Expr *
get_partition_qual_relid(Oid relid)
{
Relation rel = heap_open(relid, AccessShareLock);
Expr *result = NULL;
List *and_args;
/* Do the work only if this relation is a partition. */
if (rel->rd_rel->relispartition)
{
and_args = generate_partition_qual(rel);
if (and_args == NIL)
result = NULL;
else if (list_length(and_args) > 1)
result = makeBoolExpr(AND_EXPR, and_args, -1);
else
result = linitial(and_args);
}
/* Keep the lock. */
heap_close(rel, NoLock);
return result;
}
/*
* generate_partition_qual
*
* Generate partition predicate from rel's partition bound expression. The
* function returns a NIL list if there is no predicate.
*
* Result expression tree is stored CacheMemoryContext to ensure it survives
* as long as the relcache entry. But we should be running in a less long-lived
* working context. To avoid leaking cache memory if this routine fails partway
* through, we build in working memory and then copy the completed structure
* into cache memory.
*/
static List *
generate_partition_qual(Relation rel)
{
HeapTuple tuple;
MemoryContext oldcxt;
Datum boundDatum;
bool isnull;
PartitionBoundSpec *bound;
List *my_qual = NIL,
*result = NIL;
Relation parent;
bool found_whole_row;
/* Guard against stack overflow due to overly deep partition tree */
check_stack_depth();
/* Quick copy */
if (rel->rd_partcheck != NIL)
return copyObject(rel->rd_partcheck);
/* Grab at least an AccessShareLock on the parent table */
parent = heap_open(get_partition_parent(RelationGetRelid(rel)),
AccessShareLock);
/* Get pg_class.relpartbound */
tuple = SearchSysCache1(RELOID, RelationGetRelid(rel));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u",
RelationGetRelid(rel));
boundDatum = SysCacheGetAttr(RELOID, tuple,
Anum_pg_class_relpartbound,
&isnull);
if (isnull) /* should not happen */
elog(ERROR, "relation \"%s\" has relpartbound = null",
RelationGetRelationName(rel));
bound = castNode(PartitionBoundSpec,
stringToNode(TextDatumGetCString(boundDatum)));
ReleaseSysCache(tuple);
my_qual = get_qual_from_partbound(rel, parent, bound);
/* Add the parent's quals to the list (if any) */
if (parent->rd_rel->relispartition)
result = list_concat(generate_partition_qual(parent), my_qual);
else
result = my_qual;
/*
* Change Vars to have partition's attnos instead of the parent's. We do
* this after we concatenate the parent's quals, because we want every Var
* in it to bear this relation's attnos. It's safe to assume varno = 1
* here.
*/
result = map_partition_varattnos(result, 1, rel, parent,
&found_whole_row);
/* There can never be a whole-row reference here */
if (found_whole_row)
elog(ERROR, "unexpected whole-row reference found in partition key");
/* Save a copy in the relcache */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
rel->rd_partcheck = copyObject(result);
MemoryContextSwitchTo(oldcxt);
/* Keep the parent locked until commit */
heap_close(parent, NoLock);
return result;
}
/*
* qsort_partition_hbound_cmp
*
* We sort hash bounds by modulus, then by remainder.
*/
static int32
qsort_partition_hbound_cmp(const void *a, const void *b)
{
PartitionHashBound *h1 = (*(PartitionHashBound *const *) a);
PartitionHashBound *h2 = (*(PartitionHashBound *const *) b);
return partition_hbound_cmp(h1->modulus, h1->remainder,
h2->modulus, h2->remainder);
}
/*
* qsort_partition_list_value_cmp
*
* Compare two list partition bound datums
*/
static int32
qsort_partition_list_value_cmp(const void *a, const void *b, void *arg)
{
Datum val1 = (*(const PartitionListValue **) a)->value,
val2 = (*(const PartitionListValue **) b)->value;
PartitionKey key = (PartitionKey) arg;
return DatumGetInt32(FunctionCall2Coll(&key->partsupfunc[0],
key->partcollation[0],
val1, val2));
}
/* Used when sorting range bounds across all range partitions */
static int32
qsort_partition_rbound_cmp(const void *a, const void *b, void *arg)
{
PartitionRangeBound *b1 = (*(PartitionRangeBound *const *) a);
PartitionRangeBound *b2 = (*(PartitionRangeBound *const *) b);
PartitionKey key = (PartitionKey) arg;
return partition_rbound_cmp(key->partnatts, key->partsupfunc,
key->partcollation, b1->datums, b1->kind,
b1->lower, b2);
}