OID lookup, constants cache, and utility functions for ProvSQL. More...

#include "postgres.h"
#include "access/htup_details.h"
#include "miscadmin.h"
#include "catalog/namespace.h"
#include "catalog/pg_type.h"
#include "catalog/pg_enum.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_operator.h"
#include "fmgr.h"
#include "nodes/value.h"
#include "parser/parse_func.h"
#include "utils/syscache.h"
#include "utils/lsyscache.h"
#include "provsql_utils.h"

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Go to the source code of this file.

Macros
#define	CheckOid(o)

#define	GET_GATE_TYPE_OID(x)

Functions
static Oid	binary_oper_exact (List *opname, Oid arg1, Oid arg2)
	Look up an exactly matching binary operator OID.

Oid	find_equality_operator (Oid ltypeId, Oid rtypeId)
	Find the equality operator OID for two given types.

static Oid	get_func_oid (char *s)
	Return the OID of a globally qualified function named `s`.

static Oid	get_provsql_func_oid (char *s)
	Return the OID of a `provsql-schema` function named `s`.

static void	OperatorGet (const char operatorName, Oid operatorNamespace, Oid leftObjectId, Oid rightObjectId, Oid operatorObjectId, Oid *functionObjectId)
	Retrieve operator and function OIDs for a named operator.

static Oid	get_enum_oid (Oid enumtypoid, const char *label)
	Return the OID of a specific enum label within an enum type.

static constants_t	initialize_constants (bool failure_if_not_possible)
	Query the system catalogs to populate a fresh `constants_t`.

constants_t	get_constants (bool failure_if_not_possible)
	Retrieve the cached OID constants for the current database.

Datum	reset_constants_cache (PG_FUNCTION_ARGS)
	SQL function to invalidate the OID constants cache.

Variables
const char *	gate_type_name []
	Names of gate types.

database_constants_t *	constants_cache
	Per-database OID constants cache (sorted by database OID)

unsigned	constants_cache_len =0
	Number of valid entries in `constants_cache`.

Detailed Description

OID lookup, constants cache, and utility functions for ProvSQL.

Implements the functions declared in provsql_utils.h:

get_constants(): retrieves and caches per-database OIDs for all ProvSQL types, functions, and operators.
find_equality_operator(): looks up the = operator OID for a given pair of types.

The constants cache is a sorted, dynamically-grown array of database_constants_t records (one per PostgreSQL database OID) stored in process-local memory and searched with binary search. The reset_constants_cache() SQL function forces a cache invalidation for the current database, which is needed after ALTER EXTENSION.

Several helper functions (get_func_oid, get_provsql_func_oid, OperatorGet, get_enum_oid, binary_oper_exact) are adapted from PostgreSQL source code that is not exported as a public API.

Definition in file provsql_utils.c.

Macro Definition Documentation

◆ CheckOid

#define CheckOid ( o )

Value:

            if(constants.o==InvalidOid) { \
            if(failure_if_not_possible) \
            provsql_error("Could not initialize provsql constants"); \
            else \
            return constants; }

◆ GET_GATE_TYPE_OID

#define GET_GATE_TYPE_OID ( x )

Value:

            { \
            constants.GATE_TYPE_TO_OID[gate_ ## x] = get_enum_oid( \
              constants.OID_TYPE_GATE_TYPE, \
              #x); \
            if(constants.GATE_TYPE_TO_OID[gate_ ## x]==InvalidOid) \
            provsql_error("Could not initialize provsql gate type " #x); }

Function Documentation

◆ binary_oper_exact()

static Oid binary_oper_exact	(	List *	opname,
		Oid	arg1,
		Oid	arg2
	)

static

Look up an exactly matching binary operator OID.

Copied and adapted from parse_oper.c (PostgreSQL internals, not exported). Returns InvalidOid if no exact match exists.

Parameters

opname	Qualified operator name (a `List` of `String` nodes).
arg1	OID of the left operand type.
arg2	OID of the right operand type.

Returns: OID of the matching operator, or InvalidOid.

Definition at line 69 of file provsql_utils.c.

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◆ find_equality_operator()

Oid find_equality_operator	(	Oid	ltypeId,
		Oid	rtypeId
	)

Find the equality operator OID for two given types.

Searches pg_operator for the = operator that accepts ltypeId on the left and rtypeId on the right.

Parameters

ltypeId	OID of the left operand type.
rtypeId	OID of the right operand type.

Returns: The operator OID, or InvalidOid if none is found.

Definition at line 109 of file provsql_utils.c.

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◆ get_constants()

constants_t get_constants ( bool failure_if_not_possible )

Retrieve the cached OID constants for the current database.

On first call (or after a cache miss) this function looks up the OIDs of all ProvSQL-specific types, functions, and operators in the system catalogs and stores them in a per-database cache. Subsequent calls return the cached values without touching the catalogs.

Parameters

failure_if_not_possible If true, call provsql_error when the ProvSQL schema cannot be found (e.g. the extension is not installed in the current database). If false, return a constants_t with ok==false instead of aborting.

Returns: A constants_t whose ok field is true on success.

Definition at line 425 of file provsql_utils.c.

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◆ get_enum_oid()

static Oid get_enum_oid	(	Oid	enumtypoid,
		const char *	label
	)

static

Return the OID of a specific enum label within an enum type.

Parameters

enumtypoid	OID of the enum type (e.g. `provenance_gate`).
label	C-string label of the enum value to look up.

Returns: OID of the enum label's pg_enum row.

Definition at line 253 of file provsql_utils.c.

◆ get_func_oid()

static Oid get_func_oid ( char * s )

static

Return the OID of a globally qualified function named s.

Looks up the function in the default search path. Returns 0 if no matching function is found.

Parameters

s	Function name (unqualified).

Returns: OID of the function, or 0 if not found.

Definition at line 149 of file provsql_utils.c.

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◆ get_provsql_func_oid()

static Oid get_provsql_func_oid ( char * s )

static

Return the OID of a provsql-schema function named s.

Looks up the function in the provsql schema. Returns 0 if not found.

Parameters

s	Function name (without schema prefix).

Returns: OID of the function, or 0 if not found.

Definition at line 175 of file provsql_utils.c.

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◆ initialize_constants()

static constants_t initialize_constants ( bool failure_if_not_possible )

static

Query the system catalogs to populate a fresh constants_t.

Performs all OID lookups required by ProvSQL in a single pass through the system caches. The CheckOid() macro aborts (or returns early, depending on failure_if_not_possible) if any OID resolves to InvalidOid.

Parameters

failure_if_not_possible If true, raise a provsql_error when any OID cannot be resolved. If false, return a constants_t with ok==false instead.

Returns: Fully populated constants_t on success, or ok==false on failure when failure_if_not_possible is false.

Abort or return early if OID field o of constants is invalid.

Look up the OID of provenance_gate enum value x and store it in constants.

Definition at line 288 of file provsql_utils.c.

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◆ OperatorGet()

static void OperatorGet	(	const char *	operatorName,
		Oid	operatorNamespace,
		Oid	leftObjectId,
		Oid	rightObjectId,
		Oid *	operatorObjectId,
		Oid *	functionObjectId
	)

static

Retrieve operator and function OIDs for a named operator.

Copied and adapted from pg_operator.c (PostgreSQL internals, not exported). Looks up the operator by name, namespace, and operand types in the system cache.

Parameters

operatorName	Operator symbol string (e.g. `"<>"`).
operatorNamespace	OID of the schema containing the operator.
leftObjectId	OID of the left operand type.
rightObjectId	OID of the right operand type.
operatorObjectId	Output: OID of the operator, or 0 if not found.
functionObjectId	Output: OID of the underlying function, or 0.

Definition at line 207 of file provsql_utils.c.

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◆ reset_constants_cache()

Datum reset_constants_cache ( PG_FUNCTION_ARGS )

SQL function to invalidate the OID constants cache.

Forces a fresh OID lookup for the current database on the next call to get_constants(). Must be called after ALTER EXTENSION provsql UPDATE to ensure cached OIDs are refreshed.

Returns: Void datum.

Definition at line 466 of file provsql_utils.c.

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Variable Documentation

◆ constants_cache

database_constants_t* constants_cache

Per-database OID constants cache (sorted by database OID)

Definition at line 422 of file provsql_utils.c.

◆ constants_cache_len

unsigned constants_cache_len =0

Number of valid entries in constants_cache.

Definition at line 423 of file provsql_utils.c.

◆ gate_type_name

const char* gate_type_name[]

Initial value:

= {
  "input",
  "plus",
  "times",
  "monus",
  "project",
  "zero",
  "one",
  "eq",
  "agg",
  "semimod",
  "cmp",
  "delta",
  "value",
  "mulinput",
  "update",
  "invalid"
}

Names of gate types.

Definition at line 38 of file provsql_utils.c.

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ CheckOid

◆ GET_GATE_TYPE_OID

Function Documentation

◆ binary_oper_exact()

◆ find_equality_operator()

◆ get_constants()

◆ get_enum_oid()

◆ get_func_oid()

◆ get_provsql_func_oid()

◆ initialize_constants()

◆ OperatorGet()

◆ reset_constants_cache()

Variable Documentation

◆ constants_cache

◆ constants_cache_len

◆ gate_type_name