upstream/postgresql
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2026-03-12 05:32:27 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions
postgresql/src/include/catalog/namespace.h
Tom Lane 8f59f6b9c0 Improve performance of "simple expressions" in PL/pgSQL. 
For relatively simple expressions (say, "x + 1" or "x > 0"), plpgsql's
management overhead exceeds the cost of evaluating the expression.
This patch substantially improves that situation, providing roughly
2X speedup for such trivial expressions.

First, add infrastructure in the plancache to allow fast re-validation
of cached plans that contain no table access, and hence need no locks.
Teach plpgsql to use this infrastructure for expressions that it's
already deemed "simple" (which in particular will never contain table
references).

The fast path still requires checking that search_path hasn't changed,
so provide a fast path for OverrideSearchPathMatchesCurrent by
counting changes that have occurred to the active search path in the
current session.  This is simplistic but seems enough for now, seeing
that PushOverrideSearchPath is not used in any performance-critical
cases.

Second, manage the refcounts on simple expressions' cached plans using
a transaction-lifespan resource owner, so that we only need to take
and release an expression's refcount once per transaction not once per
expression evaluation.  The management of this resource owner exactly
parallels the existing management of plpgsql's simple-expression EState.

Add some regression tests covering this area, in particular verifying
that expression caching doesn't break semantics for search_path changes.

Patch by me, but it owes something to previous work by Amit Langote,
who recognized that getting rid of plancache-related overhead would
be a useful thing to do here.  Also thanks to Andres Freund for review.

Discussion: https://postgr.es/m/CAFj8pRDRVfLdAxsWeVLzCAbkLFZhW549K+67tpOc-faC8uH8zw@mail.gmail.com
2020-03-26 18:58:57 -04:00

188 lines
7.1 KiB
C
Raw Blame History

/*-------------------------------------------------------------------------
*
* namespace.h
* prototypes for functions in backend/catalog/namespace.c
*
*
* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/catalog/namespace.h
*
*-------------------------------------------------------------------------
*/
#ifndef NAMESPACE_H
#define NAMESPACE_H
#include "nodes/primnodes.h"
#include "storage/lock.h"
/*
* This structure holds a list of possible functions or operators
* found by namespace lookup. Each function/operator is identified
* by OID and by argument types; the list must be pruned by type
* resolution rules that are embodied in the parser, not here.
* See FuncnameGetCandidates's comments for more info.
*/
typedef struct _FuncCandidateList
{
struct _FuncCandidateList *next;
int pathpos; /* for internal use of namespace lookup */
Oid oid; /* the function or operator's OID */
int nargs; /* number of arg types returned */
int nvargs; /* number of args to become variadic array */
int ndargs; /* number of defaulted args */
int *argnumbers; /* args' positional indexes, if named call */
Oid args[FLEXIBLE_ARRAY_MEMBER]; /* arg types */
} *FuncCandidateList;
/*
* Result of checkTempNamespaceStatus
*/
typedef enum TempNamespaceStatus
{
TEMP_NAMESPACE_NOT_TEMP, /* nonexistent, or non-temp namespace */
TEMP_NAMESPACE_IDLE, /* exists, belongs to no active session */
TEMP_NAMESPACE_IN_USE /* belongs to some active session */
} TempNamespaceStatus;
/*
* Structure for xxxOverrideSearchPath functions
*
* The generation counter is private to namespace.c and shouldn't be touched
* by other code. It can be initialized to zero if necessary (that means
* "not known equal to the current active path").
*/
typedef struct OverrideSearchPath
{
List *schemas; /* OIDs of explicitly named schemas */
bool addCatalog; /* implicitly prepend pg_catalog? */
bool addTemp; /* implicitly prepend temp schema? */
uint64 generation; /* for quick detection of equality to active */
} OverrideSearchPath;
/*
* Option flag bits for RangeVarGetRelidExtended().
*/
typedef enum RVROption
{
RVR_MISSING_OK = 1 << 0, /* don't error if relation doesn't exist */
RVR_NOWAIT = 1 << 1, /* error if relation cannot be locked */
RVR_SKIP_LOCKED = 1 << 2 /* skip if relation cannot be locked */
} RVROption;
typedef void (*RangeVarGetRelidCallback) (const RangeVar *relation, Oid relId,
Oid oldRelId, void *callback_arg);
#define RangeVarGetRelid(relation, lockmode, missing_ok) \
RangeVarGetRelidExtended(relation, lockmode, \
(missing_ok) ? RVR_MISSING_OK : 0, NULL, NULL)
extern Oid RangeVarGetRelidExtended(const RangeVar *relation,
LOCKMODE lockmode, uint32 flags,
RangeVarGetRelidCallback callback,
void *callback_arg);
extern Oid RangeVarGetCreationNamespace(const RangeVar *newRelation);
extern Oid RangeVarGetAndCheckCreationNamespace(RangeVar *newRelation,
LOCKMODE lockmode,
Oid *existing_relation_id);
extern void RangeVarAdjustRelationPersistence(RangeVar *newRelation, Oid nspid);
extern Oid RelnameGetRelid(const char *relname);
extern bool RelationIsVisible(Oid relid);
extern Oid TypenameGetTypid(const char *typname);
extern Oid TypenameGetTypidExtended(const char *typname, bool temp_ok);
extern bool TypeIsVisible(Oid typid);
extern FuncCandidateList FuncnameGetCandidates(List *names,
int nargs, List *argnames,
bool expand_variadic,
bool expand_defaults,
bool missing_ok);
extern bool FunctionIsVisible(Oid funcid);
extern Oid OpernameGetOprid(List *names, Oid oprleft, Oid oprright);
extern FuncCandidateList OpernameGetCandidates(List *names, char oprkind,
bool missing_schema_ok);
extern bool OperatorIsVisible(Oid oprid);
extern Oid OpclassnameGetOpcid(Oid amid, const char *opcname);
extern bool OpclassIsVisible(Oid opcid);
extern Oid OpfamilynameGetOpfid(Oid amid, const char *opfname);
extern bool OpfamilyIsVisible(Oid opfid);
extern Oid CollationGetCollid(const char *collname);
extern bool CollationIsVisible(Oid collid);
extern Oid ConversionGetConid(const char *conname);
extern bool ConversionIsVisible(Oid conid);
extern Oid get_statistics_object_oid(List *names, bool missing_ok);
extern bool StatisticsObjIsVisible(Oid relid);
extern Oid get_ts_parser_oid(List *names, bool missing_ok);
extern bool TSParserIsVisible(Oid prsId);
extern Oid get_ts_dict_oid(List *names, bool missing_ok);
extern bool TSDictionaryIsVisible(Oid dictId);
extern Oid get_ts_template_oid(List *names, bool missing_ok);
extern bool TSTemplateIsVisible(Oid tmplId);
extern Oid get_ts_config_oid(List *names, bool missing_ok);
extern bool TSConfigIsVisible(Oid cfgid);
extern void DeconstructQualifiedName(List *names,
char **nspname_p,
char **objname_p);
extern Oid LookupNamespaceNoError(const char *nspname);
extern Oid LookupExplicitNamespace(const char *nspname, bool missing_ok);
extern Oid get_namespace_oid(const char *nspname, bool missing_ok);
extern Oid LookupCreationNamespace(const char *nspname);
extern void CheckSetNamespace(Oid oldNspOid, Oid nspOid);
extern Oid QualifiedNameGetCreationNamespace(List *names, char **objname_p);
extern RangeVar *makeRangeVarFromNameList(List *names);
extern char *NameListToString(List *names);
extern char *NameListToQuotedString(List *names);
extern bool isTempNamespace(Oid namespaceId);
extern bool isTempToastNamespace(Oid namespaceId);
extern bool isTempOrTempToastNamespace(Oid namespaceId);
extern bool isAnyTempNamespace(Oid namespaceId);
extern bool isOtherTempNamespace(Oid namespaceId);
extern TempNamespaceStatus checkTempNamespaceStatus(Oid namespaceId);
extern int GetTempNamespaceBackendId(Oid namespaceId);
extern Oid GetTempToastNamespace(void);
extern void GetTempNamespaceState(Oid *tempNamespaceId,
Oid *tempToastNamespaceId);
extern void SetTempNamespaceState(Oid tempNamespaceId,
Oid tempToastNamespaceId);
extern void ResetTempTableNamespace(void);
extern OverrideSearchPath *GetOverrideSearchPath(MemoryContext context);
extern OverrideSearchPath *CopyOverrideSearchPath(OverrideSearchPath *path);
extern bool OverrideSearchPathMatchesCurrent(OverrideSearchPath *path);
extern void PushOverrideSearchPath(OverrideSearchPath *newpath);
extern void PopOverrideSearchPath(void);
extern Oid get_collation_oid(List *collname, bool missing_ok);
extern Oid get_conversion_oid(List *conname, bool missing_ok);
extern Oid FindDefaultConversionProc(int32 for_encoding, int32 to_encoding);
/* initialization & transaction cleanup code */
extern void InitializeSearchPath(void);
extern void AtEOXact_Namespace(bool isCommit, bool parallel);
extern void AtEOSubXact_Namespace(bool isCommit, SubTransactionId mySubid,
SubTransactionId parentSubid);
/* stuff for search_path GUC variable */
extern char *namespace_search_path;
extern List *fetch_search_path(bool includeImplicit);
extern int fetch_search_path_array(Oid *sarray, int sarray_len);
#endif /* NAMESPACE_H */
Reference in a new issue View git blame Copy permalink