void
_PG_init(void)
{
if (!process_shared_preload_libraries_in_progress)
return;
RequestAddinShmemSpace(getMemstatSize());
RequestNamedLWLockTranche("memstat", PROCARRAY_MAXPROCS);
prev_ExecutorStart = ExecutorStart_hook;
ExecutorStart_hook = collectLocalMemoryStats;
prev_shmem_startup_hook = shmem_startup_hook;
shmem_startup_hook = allocShmem;
DefineCustomIntVariable("memstat.period",
"Sets period to collect memory statistics",
"zero means collecting after each query",
&ticPeriod,
10,
0, 60*60*24*31,
PGC_SUSET, GUC_UNIT_S,
NULL, NULL, NULL);
}
/*
* Module load callback
*/
void
_PG_init(void)
{
/*
* In order to create our shared memory area, we have to be loaded via
* shared_preload_libraries. If not, fall out without hooking into any of
* the main system. (We don't throw error here because it seems useful to
* allow the query_histogram functions to be created even when the
* module isn't active. The functions must protect themselves against
* being called then, however.)
*/
if (!process_shared_preload_libraries_in_progress)
return;
/* Define custom GUC variables. */
DefineCustomBoolVariable("query_histogram.dynamic",
"Dynamic histogram may be modified on the fly.",
NULL,
&default_histogram_dynamic,
false,
PGC_BACKEND,
0,
NULL,
NULL,
NULL);
/* Define custom GUC variables. */
DefineCustomBoolVariable("query_histogram.track_utility",
"Selects whether utility commands are tracked.",
NULL,
&default_histogram_utility,
true,
PGC_SUSET,
0,
NULL,
&set_histogram_track_utility,
&show_histogram_track_utility);
DefineCustomIntVariable("query_histogram.bin_count",
"Sets the number of bins of the histogram.",
"Zero disables collecting the histogram.",
&default_histogram_bins,
100,
0, 1000,
PGC_SUSET,
0,
NULL,
&set_histogram_bins_count_hook,
&show_histogram_bins_count_hook);
DefineCustomIntVariable("query_histogram.bin_width",
"Sets the width of the histogram bin.",
NULL,
&default_histogram_step,
100,
1, 1000,
PGC_SUSET,
GUC_UNIT_MS,
NULL,
&set_histogram_bins_width_hook,
&show_histogram_bins_width_hook);
DefineCustomIntVariable("query_histogram.sample_pct",
"What portion of the queries should be sampled (in percent).",
NULL,
&default_histogram_sample_pct,
5,
1, 100,
PGC_SUSET,
0,
NULL,
&set_histogram_sample_hook,
&show_histogram_sample_hook);
DefineCustomEnumVariable("query_histogram.histogram_type",
"Type of the histogram (how the bin width is computed).",
NULL,
&default_histogram_type,
HISTOGRAM_LINEAR,
histogram_type_options,
PGC_SUSET,
0,
NULL,
&set_histogram_type_hook,
&show_histogram_type_hook);
EmitWarningsOnPlaceholders("query_histogram");
/*
* Request additional shared resources. (These are no-ops if we're not in
* the postmaster process.) We'll allocate or attach to the shared
* resources in histogram_shmem_startup().
*/
RequestAddinShmemSpace(get_histogram_size());
RequestNamedLWLockTranche("query_histogram", 1);
/* Install hooks. */
prev_shmem_startup_hook = shmem_startup_hook;
shmem_startup_hook = histogram_shmem_startup;
prev_ExecutorStart = ExecutorStart_hook;
ExecutorStart_hook = histogram_ExecutorStart;
prev_ExecutorRun = ExecutorRun_hook;
ExecutorRun_hook = histogram_ExecutorRun;
prev_ExecutorFinish = ExecutorFinish_hook;
ExecutorFinish_hook = histogram_ExecutorFinish;
prev_ExecutorEnd = ExecutorEnd_hook;
ExecutorEnd_hook = histogram_ExecutorEnd;
prev_ProcessUtility = ProcessUtility_hook;
ProcessUtility_hook = queryhist_ProcessUtility;
}
