Dump schema with SQLITE_ERROR in thumbnails error handler.

Previous diagnostics show SQLITE_ERROR with "no such column:
icon_type" under UpgradeToVersion6().  I have a fix for this case, but
I'd like to see what the database does look like, first.

BUG=240396

Review URL: https://chromiumcodereview.appspot.com/15950007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@203323 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 57 insertions, 17 deletions

diff --git a/chrome/browser/history/thumbnail_database.cc b/chrome/browser/history/thumbnail_database.cc
index 7c89b18..a7454c7 100644
--- a/chrome/browser/history/thumbnail_database.cc
+++ b/chrome/browser/history/thumbnail_database.cc
@@ -94,9 +94,9 @@ void FillIconMapping(const sql::Statement& statement,
   icon_mapping->page_url = page_url;
 }
 
-// Attempt to pass 1000 bytes of |debug_info| into a crash dump.
-void DumpWithoutCrashing1000(const std::string& debug_info) {
-  char debug_buf[1000];
+// Attempt to pass 2000 bytes of |debug_info| into a crash dump.
+void DumpWithoutCrashing2000(const std::string& debug_info) {
+  char debug_buf[2000];
   base::strlcpy(debug_buf, debug_info.c_str(), arraysize(debug_buf));
   base::debug::Alias(&debug_buf);
 
@@ -125,7 +125,7 @@ void ReportCorrupt(sql::Connection* db, size_t startup_kb) {
                         messages.size());
 
     // SQLite returns up to 100 messages by default, trim deeper to
-    // keep close to the 1000-character size limit for dumping.
+    // keep close to the 2000-character size limit for dumping.
     //
     // TODO(shess): If the first 20 tend to be actionable, test if
     // passing the count to integrity_check makes it exit earlier.  In
@@ -137,7 +137,7 @@ void ReportCorrupt(sql::Connection* db, size_t startup_kb) {
     }
   }
 
-  DumpWithoutCrashing1000(debug_info);
+  DumpWithoutCrashing2000(debug_info);
 }
 
 void ReportError(sql::Connection* db, int error) {
@@ -146,21 +146,61 @@ void ReportError(sql::Connection* db, int error) {
   // fixed-size buffer.
   std::string debug_info;
 
-  // The error message from the failed statement (GetErrorCode()
-  // should be identical to error).
-  base::StringAppendF(&debug_info, "db error: %d/%d/%s\n",
-                      error, db->GetErrorCode(), db->GetErrorMessage());
+  // The error message from the failed operation.
+  base::StringAppendF(&debug_info, "db error: %d/%s\n",
+                      db->GetErrorCode(), db->GetErrorMessage());
 
   // System errno information.
   base::StringAppendF(&debug_info, "errno: %d\n", db->GetLastErrno());
 
+  // SQLITE_ERROR reports seem to be attempts to upgrade invalid
+  // schema, try to log that info.
+  if (error == SQLITE_ERROR) {
+    const char* kVersionSql = "SELECT value FROM meta WHERE key = 'version'";
+    if (db->IsSQLValid(kVersionSql)) {
+      sql::Statement statement(db->GetUniqueStatement(kVersionSql));
+      if (statement.Step()) {
+        debug_info += "version: ";
+        debug_info += statement.ColumnString(0);
+        debug_info += '\n';
+      } else if (statement.Succeeded()) {
+        debug_info += "version: none\n";
+      } else {
+        debug_info += "version: error\n";
+      }
+    } else {
+      debug_info += "version: invalid\n";
+    }
+
+    debug_info += "schema:\n";
+
+    // sqlite_master has columns:
+    //   type - "index" or "table".
+    //   name - name of created element.
+    //   tbl_name - name of element, or target table in case of index.
+    //   rootpage - root page of the element in database file.
+    //   sql - SQL to create the element.
+    // In general, the |sql| column is sufficient to derive the other
+    // columns.  |rootpage| is not interesting for debugging, without
+    // the contents of the database.  The COALESCE is because certain
+    // automatic elements will have a |name| but no |sql|,
+    const char* kSchemaSql = "SELECT COALESCE(sql, name) FROM sqlite_master";
+    sql::Statement statement(db->GetUniqueStatement(kSchemaSql));
+    while (statement.Step()) {
+      debug_info += statement.ColumnString(0);
+      debug_info += '\n';
+    }
+    if (!statement.Succeeded())
+      debug_info += "error\n";
+  }
+
   // TODO(shess): Think of other things to log.  Not logging the
   // statement text because the backtrace should suffice in most
   // cases.  The database schema is a possibility, but the
   // likelihood of recursive error callbacks makes that risky (same
   // reasoning applies to other data fetched from the database).
 
-  DumpWithoutCrashing1000(debug_info);
+  DumpWithoutCrashing2000(debug_info);
 }
 
 // TODO(shess): If this proves out, perhaps lift the code out to
@@ -201,24 +241,24 @@ void DatabaseErrorCallback(sql::Connection* db,
       if (rand < kCorruptReportsPerMillion)
         ReportCorrupt(db, startup_kb);
     } else if (error == SQLITE_READONLY) {
-      if (rand < kReportsPerMillion)
-        ReportError(db, error);
-
       // SQLITE_READONLY appears similar to SQLITE_CORRUPT - once it
       // is seen, it is almost guaranteed to be seen again.
       reported = true;
+
+      if (rand < kReportsPerMillion)
+        ReportError(db, error);
     } else {
-      // Only setting the flag after a report, so that later
-      // (potentially different) errors in a stream of errors can be
-      // reported.
+      // Only set the flag when making a report.  This should allow
+      // later (potentially different) errors in a stream of errors to
+      // be reported.
       //
       // TODO(shess): Would it be worthwile to audit for which cases
       // want once-only handling?  Sqlite.Error.Thumbnail shows
       // CORRUPT and READONLY as almost 95% of all reports on these
       // channels, so probably easier to just harvest from the field.
       if (rand < kReportsPerMillion) {
-        ReportError(db, error);
         reported = true;
+        ReportError(db, error);
       }
     }
   }