Add pg_diskusage function

Uses the tuplestore interface, so the code layout is slighly different from the original.

diff --git a/sql/pg_proctab.sql b/sql/pg_proctab--0.0.5.sql
similarity index 100%
rename from sql/pg_proctab.sql
rename to sql/pg_proctab--0.0.5.sql

diff --git a/src/pg_proctab.c b/src/pg_proctab.c
index 4867321d061aa8b194e21eefccc908a845e17f81..978cc533e17724b3c9e91bbdb79672227b5aaa5a 100644 (file)
--- a/src/pg_proctab.c
+++ b/src/pg_proctab.c
@@ -6,6 +6,11 @@
 #include <string.h>
 #include "fmgr.h"
 #include "funcapi.h"
+#include "miscadmin.h"
+#include "access/htup_details.h"
+#include "utils/tuplestore.h"
+#include "storage/fd.h"
+#include "utils/builtins.h"
 #include <sys/vfs.h>
 #include <unistd.h>
 #include <sys/stat.h>
@@ -53,6 +58,10 @@ enum cputime {i_user, i_nice_c, i_system, i_idle, i_iowait};
 enum loadavg {i_load1, i_load5, i_load15, i_last_pid};
 enum memusage {i_memused, i_memfree, i_memshared, i_membuffers, i_memcached,
                i_swapused, i_swapfree, i_swapcached};
+enum diskusage {i_major, i_minor, i_devname,
+        i_reads_completed, i_reads_merged, i_sectors_read, i_readtime, 
+        i_writes_completed, i_writes_merged, i_sectors_written, i_writetime, 
+        i_current_io, i_iotime,i_totaliotime};
 
 int get_proctab(FuncCallContext *, char **);
 int get_cputime(char **);
@@ -63,11 +72,13 @@ Datum pg_proctab(PG_FUNCTION_ARGS);
 Datum pg_cputime(PG_FUNCTION_ARGS);
 Datum pg_loadavg(PG_FUNCTION_ARGS);
 Datum pg_memusage(PG_FUNCTION_ARGS);
+Datum pg_diskusage(PG_FUNCTION_ARGS);
 
 PG_FUNCTION_INFO_V1(pg_proctab);
 PG_FUNCTION_INFO_V1(pg_cputime);
 PG_FUNCTION_INFO_V1(pg_loadavg);
 PG_FUNCTION_INFO_V1(pg_memusage);
+PG_FUNCTION_INFO_V1(pg_diskusage);
 
 Datum pg_proctab(PG_FUNCTION_ARGS)
 {
@@ -1060,3 +1071,108 @@ get_memusage(char **values)
 
        return 1;
 }
+
+Datum pg_diskusage(PG_FUNCTION_ARGS)
+{
+    ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+    MemoryContext per_query_ctx;
+    MemoryContext oldcontext;
+    TupleDesc   tupleDesc;
+    Tuplestorestate *tupleStore;
+
+    Datum       values[14];
+    bool        nulls[14];
+
+    char        device_name[4096];
+    struct statfs sb;
+    FILE       *fd;
+    int         ret;
+
+    int         major = 0;
+    int         minor = 0;
+    int64       reads_completed = 0;
+    int64       reads_merged = 0;
+    int64       sectors_read = 0;
+    int64       readtime = 0;
+    int64       writes_completed = 0;
+    int64       writes_merged = 0;
+    int64       sectors_written = 0;
+    int64       writetime = 0;
+    int64       current_io = 0;
+    int64       iotime = 0;
+    int64       totaliotime = 0;
+
+    elog(DEBUG5, "pg_diskusage: Entering stored function.");
+
+    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")));
+
+    per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
+    oldcontext = MemoryContextSwitchTo(per_query_ctx);
+
+    /*
+       Build a tuple descriptor for our result type 
+     */
+    if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
+        elog(ERROR, "return type must be a row type");
+
+    tupleStore = tuplestore_begin_heap(true, false, work_mem);
+    rsinfo->returnMode = SFRM_Materialize;
+    rsinfo->setResult = tupleStore;
+    rsinfo->setDesc = tupleDesc;
+
+    MemoryContextSwitchTo(oldcontext);
+
+    memset(nulls, 0, sizeof(nulls));
+    memset(values, 0, sizeof(values));
+
+#ifdef __linux__
+    if (statfs("/proc", &sb) < 0 || sb.f_type != PROC_SUPER_MAGIC)
+      {
+          elog(ERROR, "proc filesystem not mounted on /proc\n");
+          return (Datum) 0;
+      }
+    if ((fd = AllocateFile("/proc/diskstats", PG_BINARY_R)) == NULL)
+      {
+          elog(ERROR, "File not found: '/proc/diskstats'");
+          return (Datum) 0;
+      }
+
+    while ((ret =
+            fscanf(fd, "%d %d %s %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu",
+                   &major, &minor, device_name, &reads_completed,
+                   &reads_merged, &sectors_read, &readtime, &writes_completed,
+                   &writes_merged, &sectors_written, &writetime, &current_io,
+                   &iotime, &totaliotime)) != EOF)
+      {
+          values[i_major] = Int32GetDatum(major);
+          values[i_minor] = Int32GetDatum(minor);
+          values[i_devname] = CStringGetTextDatum(device_name);
+          values[i_reads_completed] = Int64GetDatumFast(reads_completed);
+          values[i_reads_merged] = Int64GetDatumFast(reads_merged);
+          values[i_sectors_read] = Int64GetDatumFast(sectors_read);
+          values[i_readtime] = Int64GetDatumFast(readtime);
+          values[i_writes_completed] = Int64GetDatumFast(writes_completed);
+          values[i_writes_merged] = Int64GetDatumFast(writes_merged);
+          values[i_sectors_written] = Int64GetDatumFast(sectors_written);
+          values[i_writetime] = Int64GetDatumFast(writetime);
+          values[i_current_io] = Int64GetDatumFast(current_io);
+          values[i_iotime] = Int64GetDatumFast(iotime);
+          values[i_totaliotime] = Int64GetDatumFast(totaliotime);
+          tuplestore_putvalues(tupleStore, tupleDesc, values, nulls);                       
+      }
+    FreeFile(fd);
+#endif                          /* __linux */
+
+    tuplestore_donestoring(tupleStore);
+
+    return (Datum) 0;
+}