codekingpro/portable-devtools

1/* ----------2 * backend_status.h3 *	  Definitions related to backend status reporting4 *5 * Copyright (c) 2001-2023, PostgreSQL Global Development Group6 *7 * src/include/utils/backend_status.h8 * ----------9 */10#ifndef BACKEND_STATUS_H11#define BACKEND_STATUS_H12 13#include "datatype/timestamp.h"14#include "libpq/pqcomm.h"15#include "miscadmin.h"			/* for BackendType */16#include "storage/backendid.h"17#include "utils/backend_progress.h"18 19 20/* ----------21 * Backend states22 * ----------23 */24typedef enum BackendState25{26	STATE_UNDEFINED,27	STATE_IDLE,28	STATE_RUNNING,29	STATE_IDLEINTRANSACTION,30	STATE_FASTPATH,31	STATE_IDLEINTRANSACTION_ABORTED,32	STATE_DISABLED33} BackendState;34 35 36/* ----------37 * Shared-memory data structures38 * ----------39 */40 41/*42 * PgBackendSSLStatus43 *44 * For each backend, we keep the SSL status in a separate struct, that45 * is only filled in if SSL is enabled.46 *47 * All char arrays must be null-terminated.48 */49typedef struct PgBackendSSLStatus50{51	/* Information about SSL connection */52	int			ssl_bits;53	char		ssl_version[NAMEDATALEN];54	char		ssl_cipher[NAMEDATALEN];55	char		ssl_client_dn[NAMEDATALEN];56 57	/*58	 * serial number is max "20 octets" per RFC 5280, so this size should be59	 * fine60	 */61	char		ssl_client_serial[NAMEDATALEN];62 63	char		ssl_issuer_dn[NAMEDATALEN];64} PgBackendSSLStatus;65 66/*67 * PgBackendGSSStatus68 *69 * For each backend, we keep the GSS status in a separate struct, that70 * is only filled in if GSS is enabled.71 *72 * All char arrays must be null-terminated.73 */74typedef struct PgBackendGSSStatus75{76	/* Information about GSSAPI connection */77	char		gss_princ[NAMEDATALEN]; /* GSSAPI Principal used to auth */78	bool		gss_auth;		/* If GSSAPI authentication was used */79	bool		gss_enc;		/* If encryption is being used */80	bool		gss_delegation; /* If credentials delegated */81 82} PgBackendGSSStatus;83 84 85/* ----------86 * PgBackendStatus87 *88 * Each live backend maintains a PgBackendStatus struct in shared memory89 * showing its current activity.  (The structs are allocated according to90 * BackendId, but that is not critical.)  Note that this is unrelated to the91 * cumulative stats system (i.e. pgstat.c et al).92 *93 * Each auxiliary process also maintains a PgBackendStatus struct in shared94 * memory.95 * ----------96 */97typedef struct PgBackendStatus98{99	/*100	 * To avoid locking overhead, we use the following protocol: a backend101	 * increments st_changecount before modifying its entry, and again after102	 * finishing a modification.  A would-be reader should note the value of103	 * st_changecount, copy the entry into private memory, then check104	 * st_changecount again.  If the value hasn't changed, and if it's even,105	 * the copy is valid; otherwise start over.  This makes updates cheap106	 * while reads are potentially expensive, but that's the tradeoff we want.107	 *108	 * The above protocol needs memory barriers to ensure that the apparent109	 * order of execution is as it desires.  Otherwise, for example, the CPU110	 * might rearrange the code so that st_changecount is incremented twice111	 * before the modification on a machine with weak memory ordering.  Hence,112	 * use the macros defined below for manipulating st_changecount, rather113	 * than touching it directly.114	 */115	int			st_changecount;116 117	/* The entry is valid iff st_procpid > 0, unused if st_procpid == 0 */118	int			st_procpid;119 120	/* Type of backends */121	BackendType st_backendType;122 123	/* Times when current backend, transaction, and activity started */124	TimestampTz st_proc_start_timestamp;125	TimestampTz st_xact_start_timestamp;126	TimestampTz st_activity_start_timestamp;127	TimestampTz st_state_start_timestamp;128 129	/* Database OID, owning user's OID, connection client address */130	Oid			st_databaseid;131	Oid			st_userid;132	SockAddr	st_clientaddr;133	char	   *st_clienthostname;	/* MUST be null-terminated */134 135	/* Information about SSL connection */136	bool		st_ssl;137	PgBackendSSLStatus *st_sslstatus;138 139	/* Information about GSSAPI connection */140	bool		st_gss;141	PgBackendGSSStatus *st_gssstatus;142 143	/* current state */144	BackendState st_state;145 146	/* application name; MUST be null-terminated */147	char	   *st_appname;148 149	/*150	 * Current command string; MUST be null-terminated. Note that this string151	 * possibly is truncated in the middle of a multi-byte character. As152	 * activity strings are stored more frequently than read, that allows to153	 * move the cost of correct truncation to the display side. Use154	 * pgstat_clip_activity() to truncate correctly.155	 */156	char	   *st_activity_raw;157 158	/*159	 * Command progress reporting.  Any command which wishes can advertise160	 * that it is running by setting st_progress_command,161	 * st_progress_command_target, and st_progress_param[].162	 * st_progress_command_target should be the OID of the relation which the163	 * command targets (we assume there's just one, as this is meant for164	 * utility commands), but the meaning of each element in the165	 * st_progress_param array is command-specific.166	 */167	ProgressCommandType st_progress_command;168	Oid			st_progress_command_target;169	int64		st_progress_param[PGSTAT_NUM_PROGRESS_PARAM];170 171	/* query identifier, optionally computed using post_parse_analyze_hook */172	uint64		st_query_id;173} PgBackendStatus;174 175 176/*177 * Macros to load and store st_changecount with appropriate memory barriers.178 *179 * Use PGSTAT_BEGIN_WRITE_ACTIVITY() before, and PGSTAT_END_WRITE_ACTIVITY()180 * after, modifying the current process's PgBackendStatus data.  Note that,181 * since there is no mechanism for cleaning up st_changecount after an error,182 * THESE MACROS FORM A CRITICAL SECTION.  Any error between them will be183 * promoted to PANIC, causing a database restart to clean up shared memory!184 * Hence, keep the critical section as short and straight-line as possible.185 * Aside from being safer, that minimizes the window in which readers will186 * have to loop.187 *188 * Reader logic should follow this sketch:189 *190 *		for (;;)191 *		{192 *			int before_ct, after_ct;193 *194 *			pgstat_begin_read_activity(beentry, before_ct);195 *			... copy beentry data to local memory ...196 *			pgstat_end_read_activity(beentry, after_ct);197 *			if (pgstat_read_activity_complete(before_ct, after_ct))198 *				break;199 *			CHECK_FOR_INTERRUPTS();200 *		}201 *202 * For extra safety, we generally use volatile beentry pointers, although203 * the memory barriers should theoretically be sufficient.204 */205#define PGSTAT_BEGIN_WRITE_ACTIVITY(beentry) \206	do { \207		START_CRIT_SECTION(); \208		(beentry)->st_changecount++; \209		pg_write_barrier(); \210	} while (0)211 212#define PGSTAT_END_WRITE_ACTIVITY(beentry) \213	do { \214		pg_write_barrier(); \215		(beentry)->st_changecount++; \216		Assert(((beentry)->st_changecount & 1) == 0); \217		END_CRIT_SECTION(); \218	} while (0)219 220#define pgstat_begin_read_activity(beentry, before_changecount) \221	do { \222		(before_changecount) = (beentry)->st_changecount; \223		pg_read_barrier(); \224	} while (0)225 226#define pgstat_end_read_activity(beentry, after_changecount) \227	do { \228		pg_read_barrier(); \229		(after_changecount) = (beentry)->st_changecount; \230	} while (0)231 232#define pgstat_read_activity_complete(before_changecount, after_changecount) \233	((before_changecount) == (after_changecount) && \234	 ((before_changecount) & 1) == 0)235 236 237/* ----------238 * LocalPgBackendStatus239 *240 * When we build the backend status array, we use LocalPgBackendStatus to be241 * able to add new values to the struct when needed without adding new fields242 * to the shared memory. It contains the backend status as a first member.243 * ----------244 */245typedef struct LocalPgBackendStatus246{247	/*248	 * Local version of the backend status entry.249	 */250	PgBackendStatus backendStatus;251 252	/*253	 * The backend ID.  For auxiliary processes, this will be set to a value254	 * greater than MaxBackends (since auxiliary processes do not have proper255	 * backend IDs).256	 */257	BackendId	backend_id;258 259	/*260	 * The xid of the current transaction if available, InvalidTransactionId261	 * if not.262	 */263	TransactionId backend_xid;264 265	/*266	 * The xmin of the current session if available, InvalidTransactionId if267	 * not.268	 */269	TransactionId backend_xmin;270 271	/*272	 * Number of cached subtransactions in the current session.273	 */274	int			backend_subxact_count;275 276	/*277	 * The number of subtransactions in the current session which exceeded the278	 * cached subtransaction limit.279	 */280	bool		backend_subxact_overflowed;281} LocalPgBackendStatus;282 283 284/* ----------285 * GUC parameters286 * ----------287 */288extern PGDLLIMPORT bool pgstat_track_activities;289extern PGDLLIMPORT int pgstat_track_activity_query_size;290 291 292/* ----------293 * Other global variables294 * ----------295 */296extern PGDLLIMPORT PgBackendStatus *MyBEEntry;297 298 299/* ----------300 * Functions called from postmaster301 * ----------302 */303extern Size BackendStatusShmemSize(void);304extern void CreateSharedBackendStatus(void);305 306 307/* ----------308 * Functions called from backends309 * ----------310 */311 312/* Initialization functions */313extern void pgstat_beinit(void);314extern void pgstat_bestart(void);315 316extern void pgstat_clear_backend_activity_snapshot(void);317 318/* Activity reporting functions */319extern void pgstat_report_activity(BackendState state, const char *cmd_str);320extern void pgstat_report_query_id(uint64 query_id, bool force);321extern void pgstat_report_tempfile(size_t filesize);322extern void pgstat_report_appname(const char *appname);323extern void pgstat_report_xact_timestamp(TimestampTz tstamp);324extern const char *pgstat_get_backend_current_activity(int pid, bool checkUser);325extern const char *pgstat_get_crashed_backend_activity(int pid, char *buffer,326													   int buflen);327extern uint64 pgstat_get_my_query_id(void);328 329 330/* ----------331 * Support functions for the SQL-callable functions to332 * generate the pgstat* views.333 * ----------334 */335extern int	pgstat_fetch_stat_numbackends(void);336extern PgBackendStatus *pgstat_get_beentry_by_backend_id(BackendId beid);337extern LocalPgBackendStatus *pgstat_get_local_beentry_by_backend_id(BackendId beid);338extern LocalPgBackendStatus *pgstat_get_local_beentry_by_index(int idx);339extern char *pgstat_clip_activity(const char *raw_activity);340 341 342#endif							/* BACKEND_STATUS_H */343