From f91feba8776eb66008cdb73b3a8c0c7c08cc54d9 Mon Sep 17 00:00:00 2001 From: Stephen Frost Date: Fri, 8 May 2015 19:25:30 -0400 Subject: [PATCH] Modify pg_stat_get_activity to build a tuplestore This updates pg_stat_get_activity() to build a tuplestore for its results instead of using the old-style multiple-call method. This simplifies the function, though that wasn't the primary motivation for the change, which is that we may turn it into a helper function which can filter the results (or not) much more easily. --- src/backend/utils/adt/pgstatfuncs.c | 182 ++++++++++------------------ 1 file changed, 61 insertions(+), 121 deletions(-) diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index bbe94c34a15..2b3778b03ad 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -524,137 +524,75 @@ pg_stat_get_backend_idset(PG_FUNCTION_ARGS) } } +/* + * Returns activity of PG backends. + */ Datum pg_stat_get_activity(PG_FUNCTION_ARGS) { - FuncCallContext *funcctx; +#define PG_STAT_GET_ACTIVITY_COLS 22 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + TupleDesc tupdesc; + Tuplestorestate *tupstore; + MemoryContext per_query_ctx; + MemoryContext oldcontext; - if (SRF_IS_FIRSTCALL()) - { - MemoryContext oldcontext; - TupleDesc tupdesc; + /* check to see if caller supports us returning a tuplestore */ + if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("set-valued function called in context that cannot accept a set"))); + if (!(rsinfo->allowedModes & SFRM_Materialize)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("materialize mode required, but it is not " \ + "allowed in this context"))); - funcctx = SRF_FIRSTCALL_INIT(); + /* Build a tuple descriptor for our result type */ + if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE) + elog(ERROR, "return type must be a row type"); - oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx); + per_query_ctx = rsinfo->econtext->ecxt_per_query_memory; + oldcontext = MemoryContextSwitchTo(per_query_ctx); - tupdesc = CreateTemplateTupleDesc(22, false); - TupleDescInitEntry(tupdesc, (AttrNumber) 1, "datid", - OIDOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 2, "pid", - INT4OID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 3, "usesysid", - OIDOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 4, "application_name", - TEXTOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 5, "state", - TEXTOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 6, "query", - TEXTOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 7, "waiting", - BOOLOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 8, "act_start", - TIMESTAMPTZOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 9, "query_start", - TIMESTAMPTZOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 10, "backend_start", - TIMESTAMPTZOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 11, "state_change", - TIMESTAMPTZOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 12, "client_addr", - INETOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 13, "client_hostname", - TEXTOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 14, "client_port", - INT4OID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 15, "backend_xid", - XIDOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 16, "backend_xmin", - XIDOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 17, "ssl", - BOOLOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 18, "sslversion", - TEXTOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 19, "sslcipher", - TEXTOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 20, "sslbits", - INT4OID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 21, "sslcompression", - BOOLOID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 22, "sslclientdn", - TEXTOID, -1, 0); + tupstore = tuplestore_begin_heap(true, false, work_mem); + rsinfo->returnMode = SFRM_Materialize; + rsinfo->setResult = tupstore; + rsinfo->setDesc = tupdesc; - funcctx->tuple_desc = BlessTupleDesc(tupdesc); + MemoryContextSwitchTo(oldcontext); - funcctx->user_fctx = palloc0(sizeof(int)); - if (PG_ARGISNULL(0)) - { - /* Get all backends */ - funcctx->max_calls = pgstat_fetch_stat_numbackends(); - } - else - { - /* - * Get one backend - locate by pid. - * - * We lookup the backend early, so we can return zero rows if it - * doesn't exist, instead of returning a single row full of NULLs. - */ - int pid = PG_GETARG_INT32(0); - int i; - int n = pgstat_fetch_stat_numbackends(); - - for (i = 1; i <= n; i++) - { - PgBackendStatus *be = pgstat_fetch_stat_beentry(i); - - if (be) - { - if (be->st_procpid == pid) - { - *(int *) (funcctx->user_fctx) = i; - break; - } - } - } - - if (*(int *) (funcctx->user_fctx) == 0) - /* Pid not found, return zero rows */ - funcctx->max_calls = 0; - else - funcctx->max_calls = 1; - } - - MemoryContextSwitchTo(oldcontext); - } - - /* stuff done on every call of the function */ - funcctx = SRF_PERCALL_SETUP(); - - if (funcctx->call_cntr < funcctx->max_calls) + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) { /* for each row */ - Datum values[22]; - bool nulls[22]; - HeapTuple tuple; + Datum values[PG_STAT_GET_ACTIVITY_COLS]; + bool nulls[PG_STAT_GET_ACTIVITY_COLS]; LocalPgBackendStatus *local_beentry; PgBackendStatus *beentry; MemSet(values, 0, sizeof(values)); MemSet(nulls, 0, sizeof(nulls)); - if (*(int *) (funcctx->user_fctx) > 0) + if (pid != -1) { - /* Get specific pid slot */ - local_beentry = pgstat_fetch_stat_local_beentry(*(int *) (funcctx->user_fctx)); - beentry = &local_beentry->backendStatus; - } - else - { - /* Get the next one in the list */ - local_beentry = pgstat_fetch_stat_local_beentry(funcctx->call_cntr + 1); /* 1-based index */ - beentry = &local_beentry->backendStatus; + /* Skip any which are not the one we're looking for. */ + PgBackendStatus *be = pgstat_fetch_stat_beentry(curr_backend); + + if (!be || be->st_procpid != pid) + continue; + } + + /* Get the next one in the list */ + local_beentry = pgstat_fetch_stat_local_beentry(curr_backend); + if (!local_beentry) + continue; + + beentry = &local_beentry->backendStatus; if (!beentry) { int i; @@ -665,8 +603,8 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) nulls[5] = false; values[5] = CStringGetTextDatum(""); - tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls); - SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple)); + tuplestore_putvalues(tupstore, tupdesc, values, nulls); + continue; } /* Values available to all callers */ @@ -839,15 +777,17 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) nulls[13] = true; } - tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls); + tuplestore_putvalues(tupstore, tupdesc, values, nulls); - SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple)); - } - else - { - /* nothing left */ - SRF_RETURN_DONE(funcctx); + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; } + + /* clean up and return the tuplestore */ + tuplestore_donestoring(tupstore); + + return (Datum) 0; }