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Modify pg_stat_get_activity to build a tuplestore

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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.
pull/14/head
Stephen Frost 10 years ago
parent 4b342fb591
commit f91feba877
1 changed files with 67 additions and 127 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 194
      src/backend/utils/adt/pgstatfuncs.c

194
src/backend/utils/adt/pgstatfuncs.c
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@ -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;
if (SRF_IS_FIRSTCALL())
{
MemoryContext oldcontext;
TupleDesc tupdesc;
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_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);
funcctx->tuple_desc = BlessTupleDesc(tupdesc);
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)
#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;
/* 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")));
/* 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");
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
tupstore = tuplestore_begin_heap(true, false, work_mem);
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
/* 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)
{
/* Get specific pid slot */
local_beentry = pgstat_fetch_stat_local_beentry(*(int *) (funcctx->user_fctx));
beentry = &local_beentry->backendStatus;
}
else
if (pid != -1)
{
/* 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("<backend information not available>");
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;
}

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