session.h

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/*-------------------------------------------------------------------------
 *
 * session.h
 *    Encapsulation of user session.
 *
 * Copyright (c) 2017-2024, PostgreSQL Global Development Group
 *
 * src/include/access/session.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef SESSION_H
#define SESSION_H
 
#include "lib/dshash.h"
 
/* Avoid including typcache.h */
struct SharedRecordTypmodRegistry;
 
/*
 * A struct encapsulating some elements of a user's session.  For now this
 * manages state that applies to parallel query, but in principle it could
 * include other things that are currently global variables.
 */
typedef struct Session
{
    dsm_segment *segment;       /* The session-scoped DSM segment. */
    dsa_area   *area;           /* The session-scoped DSA area. */
 
    /* State managed by typcache.c. */
    struct SharedRecordTypmodRegistry *shared_typmod_registry;
    dshash_table *shared_record_table;
    dshash_table *shared_typmod_table;
} Session;
 
extern void InitializeSession(void);
extern dsm_handle GetSessionDsmHandle(void);
extern void AttachSession(dsm_handle handle);
extern void DetachSession(void);
 
/* The current session, or NULL for none. */
extern PGDLLIMPORT Session *CurrentSession;
 
#endif                          /* SESSION_H */