Enhance the ".stats" command in sqlite3.exe to show one-time stats information

if invoked with one argument.  Also show /proc/PID/io information if run on
Linux.

FossilOrigin-Name: 3c36948f16b58fe8042c37d0df634308b4e48217

manifest

@@ -1,5 +1,5 @@
-C Fix\sa\srequirement\smark\sto\sconform\sto\sa\stypo\sfix\sin\sthe\sdocumentation.
+C Enhance\sthe\s".stats"\scommand\sin\ssqlite3.exe\sto\sshow\sone-time\sstats\sinformation\nif\sinvoked\swith\sone\sargument.\s\sAlso\sshow\s/proc/PID/io\sinformation\sif\srun\son\nLinux.
-D 2016-02-27T14:04:27.011
+D 2016-02-27T17:12:36.918
 F Makefile.in 4e90dc1521879022aa9479268a4cd141d1771142
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 4f319afb7c049d40aff7af6e8c4e7cc2ba18e079
@@ -350,7 +350,7 @@ F src/random.c ba2679f80ec82c4190062d756f22d0c358180696
 F src/resolve.c b8f7174e5f8c33c44ded3a25a973d0bb89228c20
 F src/rowset.c 9fe4b3ad7cc00944386bb600233d8f523de07a6e
 F src/select.c 1bacfde7b7cec134d2b354cbcf67bafc67078431
-F src/shell.c 89b73e894e737cc2f21e4bce0feb3ea21cc61124
+F src/shell.c f30efdd675007ec6006d51193fc47aabda2984a5
 F src/sqlite.h.in 57d2a02b14c9ec4f7cb294153eaf62294dc5aa68
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h dfbe62ffd95b99afe2140d8c35b180d11924072d
@@ -1020,10 +1020,10 @@ F test/sharedA.test 0cdf1a76dfa00e6beee66af5b534b1e8df2720f5
 F test/sharedB.test 16cc7178e20965d75278f410943109b77b2e645e
 F test/shared_err.test 2f2aee20db294b9924e81f6ccbe60f19e21e8506
 F test/sharedlock.test 5ede3c37439067c43b0198f580fd374ebf15d304
-F test/shell1.test ce5e744870387164703bf2dee2cc9753e4a71513
+F test/shell1.test a45b424ec23a4b946848ff9e1af5186c677162ab
 F test/shell2.test 12b8bf901b0e3a8ac58cf5c0c63a0a388d4d1862
 F test/shell3.test 5e8545ec72c4413a0e8d4c6be56496e3c257ca29
-F test/shell4.test ddf0a99044e2245a87fc17423e3aaa1445b3243b
+F test/shell4.test f43e250139dc5dc5f0f2ec1752c50284a1ede102
 F test/shell5.test c04e9f9f948305706b88377c464c7f08ce7479f9
 F test/shortread1.test bb591ef20f0fd9ed26d0d12e80eee6d7ac8897a3
 F test/show_speedtest1_rtree.tcl 32e6c5f073d7426148a6936a0408f4b5b169aba5
@@ -1451,7 +1451,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 33dd671cb9c17f08dbc61aed91e80eaeb84bfaf5
+P d1392c627934b89cdb86d82e73d56e8f76952b30
-R 262f28bf043321d0cb2a0438d4f47c13
+R cc008a8c941c26feeb254cac8325586b
 U drh
-Z 7540cf66865728ef817082a1a3c276f6
+Z 0f34ce71f4553990685c1f98cc5c169c

manifest.uuid

@@ -1 +1 @@
-d1392c627934b89cdb86d82e73d56e8f76952b30
+3c36948f16b58fe8042c37d0df634308b4e48217

src/shell.c

@@ -1284,6 +1284,43 @@ static char *save_err_msg(
   return zErrMsg;
 }
 
+#ifdef __linux__
+/*
+** Attempt to display I/O stats on Linux using /proc/PID/io
+*/
+static void displayLinuxIoStats(FILE *out){
+  FILE *in;
+  char z[200];
+  sqlite3_snprintf(sizeof(z), z, "/proc/%d/io", getpid());
+  in = fopen(z, "rb");
+  if( in==0 ) return;
+  while( fgets(z, sizeof(z), in)!=0 ){
+    static const struct {
+      const char *zPattern;
+      const char *zDesc;
+    } aTrans[] = {
+      { "rchar: ",                  "Number of bytes received by read():" },
+      { "wchar: ",                  "Number of bytes sent to write():"    },
+      { "syscr: ",                  "Number of read() system calls:"      },
+      { "syscw: ",                  "Number of write() system calls:"     },
+      { "read_bytes: ",             "Number of bytes from storage:"       },
+      { "write_bytes: ",            "Number of bytes sent to storage:"    },
+      { "cancelled_write_bytes: ",  "Cancelled write bytes:"              },
+    };
+    int i;
+    for(i=0; i<ArraySize(aTrans); i++){
+      int n = (int)strlen(aTrans[i].zPattern);
+      if( strncmp(aTrans[i].zPattern, z, n)==0 ){
+        raw_printf(out, "%-36s %s", aTrans[i].zDesc, &z[n]);
+        break;
+      }
+    }
+  }
+  fclose(in);
+}   
+#endif
+
+
 /*
 ** Display memory stats.
 */
@@ -1406,6 +1443,10 @@ static int display_stats(
     raw_printf(pArg->out, "Virtual Machine Steps:               %d\n", iCur);
   }
 
+#ifdef __linux__
+  displayLinuxIoStats(pArg->out);
+#endif
+
   /* Do not remove this machine readable comment: extra-stats-output-here */
 
   return 0;
@@ -1957,7 +1998,7 @@ static char zHelp[] =
   "                         separator for both the output mode and .import\n"
   ".shell CMD ARGS...     Run CMD ARGS... in a system shell\n"
   ".show                  Show the current values for various settings\n"
-  ".stats on|off          Turn stats on or off\n"
+  ".stats ?on|off?        Show stats or turn stats on or off\n"
   ".system CMD ARGS...    Run CMD ARGS... in a system shell\n"
   ".tables ?TABLE?        List names of tables\n"
   "                         If TABLE specified, only list tables matching\n"
@@ -3835,8 +3876,10 @@ static int do_meta_command(char *zLine, ShellState *p){
   if( c=='s' && strncmp(azArg[0], "stats", n)==0 ){
     if( nArg==2 ){
       p->statsOn = booleanValue(azArg[1]);
+    }else if( nArg==1 ){
+      display_stats(p->db, p, 0);
     }else{
-      raw_printf(stderr, "Usage: .stats on|off\n");
+      raw_printf(stderr, "Usage: .stats ?on|off?\n");
       rc = 1;
     }
   }else

test/shell1.test

@@ -625,9 +625,9 @@ do_test shell1-3.23.2 {
 } {1 {Usage: .show}}
 
 # .stats ON|OFF          Turn stats on or off
-do_test shell1-3.23b.1 {
+#do_test shell1-3.23b.1 {
-  catchcmd "test.db" ".stats"
+#  catchcmd "test.db" ".stats"
-} {1 {Usage: .stats on|off}}
+#} {1 {Usage: .stats on|off}}
 do_test shell1-3.23b.2 {
   catchcmd "test.db" ".stats ON"
 } {0 {}}
@@ -637,7 +637,7 @@ do_test shell1-3.23b.3 {
 do_test shell1-3.23b.4 {
   # too many arguments
   catchcmd "test.db" ".stats OFF BAD"
-} {1 {Usage: .stats on|off}}
+} {1 {Usage: .stats ?on|off?}}
 
 # .tables ?TABLE?        List names of tables
 #                          If TABLE specified, only list tables matching

test/shell4.test

@@ -61,9 +61,9 @@ do_test shell4-1.2.2 {
 } {0}
 
 # .stats ON|OFF          Turn stats on or off
-do_test shell4-1.3.1 {
+#do_test shell4-1.3.1 {
-  catchcmd "test.db" ".stats"
+#  catchcmd "test.db" ".stats"
-} {1 {Usage: .stats on|off}}
+#} {1 {Usage: .stats on|off}}
 do_test shell4-1.3.2 {
   catchcmd "test.db" ".stats ON"
 } {0 {}}
@@ -73,7 +73,7 @@ do_test shell4-1.3.3 {
 do_test shell4-1.3.4 {
   # too many arguments
   catchcmd "test.db" ".stats OFF BAD"
-} {1 {Usage: .stats on|off}}
+} {1 {Usage: .stats ?on|off?}}
 
 # NB. whitespace is important
 do_test shell4-1.4.1 {