diff options
Diffstat (limited to 'src/backend/utils/adt/mcxtfuncs.c')
| -rw-r--r-- | src/backend/utils/adt/mcxtfuncs.c | 60 |
1 files changed, 59 insertions, 1 deletions
diff --git a/src/backend/utils/adt/mcxtfuncs.c b/src/backend/utils/adt/mcxtfuncs.c index c02fa47550a..e2b87a7ed9f 100644 --- a/src/backend/utils/adt/mcxtfuncs.c +++ b/src/backend/utils/adt/mcxtfuncs.c @@ -18,6 +18,8 @@ #include "funcapi.h" #include "miscadmin.h" #include "mb/pg_wchar.h" +#include "storage/proc.h" +#include "storage/procarray.h" #include "utils/builtins.h" /* ---------- @@ -61,7 +63,7 @@ PutMemoryContextsStatsTupleStore(Tuplestorestate *tupstore, /* Examine the context itself */ memset(&stat, 0, sizeof(stat)); - (*context->methods->stats) (context, NULL, (void *) &level, &stat); + (*context->methods->stats) (context, NULL, (void *) &level, &stat, true); memset(values, 0, sizeof(values)); memset(nulls, 0, sizeof(nulls)); @@ -155,3 +157,59 @@ pg_get_backend_memory_contexts(PG_FUNCTION_ARGS) return (Datum) 0; } + +/* + * pg_log_backend_memory_contexts + * Signal a backend process to log its memory contexts. + * + * Only superusers are allowed to signal to log the memory contexts + * because allowing any users to issue this request at an unbounded + * rate would cause lots of log messages and which can lead to + * denial of service. + * + * On receipt of this signal, a backend sets the flag in the signal + * handler, which causes the next CHECK_FOR_INTERRUPTS() to log the + * memory contexts. + */ +Datum +pg_log_backend_memory_contexts(PG_FUNCTION_ARGS) +{ + int pid = PG_GETARG_INT32(0); + PGPROC *proc = BackendPidGetProc(pid); + + /* + * BackendPidGetProc returns NULL if the pid isn't valid; but by the time + * we reach kill(), a process for which we get a valid proc here might + * have terminated on its own. There's no way to acquire a lock on an + * arbitrary process to prevent that. But since this mechanism is usually + * used to debug a backend running and consuming lots of memory, that it + * might end on its own first and its memory contexts are not logged is + * not a problem. + */ + if (proc == NULL) + { + /* + * This is just a warning so a loop-through-resultset will not abort + * if one backend terminated on its own during the run. + */ + ereport(WARNING, + (errmsg("PID %d is not a PostgreSQL server process", pid))); + PG_RETURN_BOOL(false); + } + + /* Only allow superusers to log memory contexts. */ + if (!superuser()) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + errmsg("must be a superuser to log memory contexts"))); + + if (SendProcSignal(pid, PROCSIG_LOG_MEMORY_CONTEXT, proc->backendId) < 0) + { + /* Again, just a warning to allow loops */ + ereport(WARNING, + (errmsg("could not send signal to process %d: %m", pid))); + PG_RETURN_BOOL(false); + } + + PG_RETURN_BOOL(true); +} |