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Diffstat (limited to 'src/include/utils/backend_status.h')
| -rw-r--r-- | src/include/utils/backend_status.h | 321 |
1 files changed, 321 insertions, 0 deletions
diff --git a/src/include/utils/backend_status.h b/src/include/utils/backend_status.h new file mode 100644 index 0000000..7403bca --- /dev/null +++ b/src/include/utils/backend_status.h @@ -0,0 +1,321 @@ +/* ---------- + * backend_status.h + * Definitions related to backend status reporting + * + * Copyright (c) 2001-2022, PostgreSQL Global Development Group + * + * src/include/utils/backend_status.h + * ---------- + */ +#ifndef BACKEND_STATUS_H +#define BACKEND_STATUS_H + +#include "datatype/timestamp.h" +#include "libpq/pqcomm.h" +#include "miscadmin.h" /* for BackendType */ +#include "utils/backend_progress.h" + + +/* ---------- + * Backend states + * ---------- + */ +typedef enum BackendState +{ + STATE_UNDEFINED, + STATE_IDLE, + STATE_RUNNING, + STATE_IDLEINTRANSACTION, + STATE_FASTPATH, + STATE_IDLEINTRANSACTION_ABORTED, + STATE_DISABLED +} BackendState; + + +/* ---------- + * Shared-memory data structures + * ---------- + */ + +/* + * PgBackendSSLStatus + * + * For each backend, we keep the SSL status in a separate struct, that + * is only filled in if SSL is enabled. + * + * All char arrays must be null-terminated. + */ +typedef struct PgBackendSSLStatus +{ + /* Information about SSL connection */ + int ssl_bits; + char ssl_version[NAMEDATALEN]; + char ssl_cipher[NAMEDATALEN]; + char ssl_client_dn[NAMEDATALEN]; + + /* + * serial number is max "20 octets" per RFC 5280, so this size should be + * fine + */ + char ssl_client_serial[NAMEDATALEN]; + + char ssl_issuer_dn[NAMEDATALEN]; +} PgBackendSSLStatus; + +/* + * PgBackendGSSStatus + * + * For each backend, we keep the GSS status in a separate struct, that + * is only filled in if GSS is enabled. + * + * All char arrays must be null-terminated. + */ +typedef struct PgBackendGSSStatus +{ + /* Information about GSSAPI connection */ + char gss_princ[NAMEDATALEN]; /* GSSAPI Principal used to auth */ + bool gss_auth; /* If GSSAPI authentication was used */ + bool gss_enc; /* If encryption is being used */ + +} PgBackendGSSStatus; + + +/* ---------- + * PgBackendStatus + * + * Each live backend maintains a PgBackendStatus struct in shared memory + * showing its current activity. (The structs are allocated according to + * BackendId, but that is not critical.) Note that this is unrelated to the + * cumulative stats system (i.e. pgstat.c et al). + * + * Each auxiliary process also maintains a PgBackendStatus struct in shared + * memory. + * ---------- + */ +typedef struct PgBackendStatus +{ + /* + * To avoid locking overhead, we use the following protocol: a backend + * increments st_changecount before modifying its entry, and again after + * finishing a modification. A would-be reader should note the value of + * st_changecount, copy the entry into private memory, then check + * st_changecount again. If the value hasn't changed, and if it's even, + * the copy is valid; otherwise start over. This makes updates cheap + * while reads are potentially expensive, but that's the tradeoff we want. + * + * The above protocol needs memory barriers to ensure that the apparent + * order of execution is as it desires. Otherwise, for example, the CPU + * might rearrange the code so that st_changecount is incremented twice + * before the modification on a machine with weak memory ordering. Hence, + * use the macros defined below for manipulating st_changecount, rather + * than touching it directly. + */ + int st_changecount; + + /* The entry is valid iff st_procpid > 0, unused if st_procpid == 0 */ + int st_procpid; + + /* Type of backends */ + BackendType st_backendType; + + /* Times when current backend, transaction, and activity started */ + TimestampTz st_proc_start_timestamp; + TimestampTz st_xact_start_timestamp; + TimestampTz st_activity_start_timestamp; + TimestampTz st_state_start_timestamp; + + /* Database OID, owning user's OID, connection client address */ + Oid st_databaseid; + Oid st_userid; + SockAddr st_clientaddr; + char *st_clienthostname; /* MUST be null-terminated */ + + /* Information about SSL connection */ + bool st_ssl; + PgBackendSSLStatus *st_sslstatus; + + /* Information about GSSAPI connection */ + bool st_gss; + PgBackendGSSStatus *st_gssstatus; + + /* current state */ + BackendState st_state; + + /* application name; MUST be null-terminated */ + char *st_appname; + + /* + * Current command string; MUST be null-terminated. Note that this string + * possibly is truncated in the middle of a multi-byte character. As + * activity strings are stored more frequently than read, that allows to + * move the cost of correct truncation to the display side. Use + * pgstat_clip_activity() to truncate correctly. + */ + char *st_activity_raw; + + /* + * Command progress reporting. Any command which wishes can advertise + * that it is running by setting st_progress_command, + * st_progress_command_target, and st_progress_param[]. + * st_progress_command_target should be the OID of the relation which the + * command targets (we assume there's just one, as this is meant for + * utility commands), but the meaning of each element in the + * st_progress_param array is command-specific. + */ + ProgressCommandType st_progress_command; + Oid st_progress_command_target; + int64 st_progress_param[PGSTAT_NUM_PROGRESS_PARAM]; + + /* query identifier, optionally computed using post_parse_analyze_hook */ + uint64 st_query_id; +} PgBackendStatus; + + +/* + * Macros to load and store st_changecount with appropriate memory barriers. + * + * Use PGSTAT_BEGIN_WRITE_ACTIVITY() before, and PGSTAT_END_WRITE_ACTIVITY() + * after, modifying the current process's PgBackendStatus data. Note that, + * since there is no mechanism for cleaning up st_changecount after an error, + * THESE MACROS FORM A CRITICAL SECTION. Any error between them will be + * promoted to PANIC, causing a database restart to clean up shared memory! + * Hence, keep the critical section as short and straight-line as possible. + * Aside from being safer, that minimizes the window in which readers will + * have to loop. + * + * Reader logic should follow this sketch: + * + * for (;;) + * { + * int before_ct, after_ct; + * + * pgstat_begin_read_activity(beentry, before_ct); + * ... copy beentry data to local memory ... + * pgstat_end_read_activity(beentry, after_ct); + * if (pgstat_read_activity_complete(before_ct, after_ct)) + * break; + * CHECK_FOR_INTERRUPTS(); + * } + * + * For extra safety, we generally use volatile beentry pointers, although + * the memory barriers should theoretically be sufficient. + */ +#define PGSTAT_BEGIN_WRITE_ACTIVITY(beentry) \ + do { \ + START_CRIT_SECTION(); \ + (beentry)->st_changecount++; \ + pg_write_barrier(); \ + } while (0) + +#define PGSTAT_END_WRITE_ACTIVITY(beentry) \ + do { \ + pg_write_barrier(); \ + (beentry)->st_changecount++; \ + Assert(((beentry)->st_changecount & 1) == 0); \ + END_CRIT_SECTION(); \ + } while (0) + +#define pgstat_begin_read_activity(beentry, before_changecount) \ + do { \ + (before_changecount) = (beentry)->st_changecount; \ + pg_read_barrier(); \ + } while (0) + +#define pgstat_end_read_activity(beentry, after_changecount) \ + do { \ + pg_read_barrier(); \ + (after_changecount) = (beentry)->st_changecount; \ + } while (0) + +#define pgstat_read_activity_complete(before_changecount, after_changecount) \ + ((before_changecount) == (after_changecount) && \ + ((before_changecount) & 1) == 0) + + +/* ---------- + * LocalPgBackendStatus + * + * When we build the backend status array, we use LocalPgBackendStatus to be + * able to add new values to the struct when needed without adding new fields + * to the shared memory. It contains the backend status as a first member. + * ---------- + */ +typedef struct LocalPgBackendStatus +{ + /* + * Local version of the backend status entry. + */ + PgBackendStatus backendStatus; + + /* + * The xid of the current transaction if available, InvalidTransactionId + * if not. + */ + TransactionId backend_xid; + + /* + * The xmin of the current session if available, InvalidTransactionId if + * not. + */ + TransactionId backend_xmin; +} LocalPgBackendStatus; + + +/* ---------- + * GUC parameters + * ---------- + */ +extern PGDLLIMPORT bool pgstat_track_activities; +extern PGDLLIMPORT int pgstat_track_activity_query_size; + + +/* ---------- + * Other global variables + * ---------- + */ +extern PGDLLIMPORT PgBackendStatus *MyBEEntry; + + +/* ---------- + * Functions called from postmaster + * ---------- + */ +extern Size BackendStatusShmemSize(void); +extern void CreateSharedBackendStatus(void); + + +/* ---------- + * Functions called from backends + * ---------- + */ + +/* Initialization functions */ +extern void pgstat_beinit(void); +extern void pgstat_bestart(void); + +extern void pgstat_clear_backend_activity_snapshot(void); + +/* Activity reporting functions */ +extern void pgstat_report_activity(BackendState state, const char *cmd_str); +extern void pgstat_report_query_id(uint64 query_id, bool force); +extern void pgstat_report_tempfile(size_t filesize); +extern void pgstat_report_appname(const char *appname); +extern void pgstat_report_xact_timestamp(TimestampTz tstamp); +extern const char *pgstat_get_backend_current_activity(int pid, bool checkUser); +extern const char *pgstat_get_crashed_backend_activity(int pid, char *buffer, + int buflen); +extern uint64 pgstat_get_my_query_id(void); + + +/* ---------- + * Support functions for the SQL-callable functions to + * generate the pgstat* views. + * ---------- + */ +extern int pgstat_fetch_stat_numbackends(void); +extern PgBackendStatus *pgstat_fetch_stat_beentry(int beid); +extern LocalPgBackendStatus *pgstat_fetch_stat_local_beentry(int beid); +extern char *pgstat_clip_activity(const char *raw_activity); + + +#endif /* BACKEND_STATUS_H */ |