MDEV-28471 mysql_install_db.exe does not work with --innodb-page-size=64K

The error message "InnoDB: innodb_page_size=65536 requires innodb_buffer_pool_size >= 20MiB current 10MiB" is the relevant one.

The root cause:
mysql_install_db bootstraps with --innodb-buffer-pool-size=10M.
Small bufferpool is here by design - bootstrap should succeed,
even if there is not much RAM available, bootstrap does not need that much
memory.

For pagesize 64K specifically, Innodb thinks it needs a larger bufferpool,
and thus it lets the bootstrap process die (although the expected behavior
in this case would be to adjust value, give warning and continue)

The workaround:
- pass --innodb-buffer-pool-size=20M, which is suitable for all page sizes.
- check the same limit in MSI custom action.

Also, the patch adds mtr test for 64K page size.

3 files changed, 37 insertions, 21 deletions

diff --git a/mysql-test/main/mysql_install_db_win.test b/mysql-test/main/mysql_install_db_win.test
index ceb7293f611..c400dbf3fb9 100644
--- a/mysql-test/main/mysql_install_db_win.test
+++ b/mysql-test/main/mysql_install_db_win.test
@@ -42,6 +42,13 @@ remove_file $log;
 
 rmdir $ddir;
 
+# MDEV-28471 - mysql_install_db.exe fails with --innodb-page-size=64K
+--disable_result_log
+exec $MYSQL_INSTALL_DB_EXE --datadir=$ddir --password=foo -R --innodb-page-size=64K --verbose
+--enable_result_log
+rmdir $ddir;
+
+# Tests with config file
 let $restart_parameters=;
 connection default;
 
diff --git a/sql/mysql_install_db.cc b/sql/mysql_install_db.cc
index 713c6ac4c3f..1e79e6444ff 100644
--- a/sql/mysql_install_db.cc
+++ b/sql/mysql_install_db.cc
@@ -333,7 +333,7 @@ static char *init_bootstrap_command_line(char *cmdline, size_t size)
     " %s"
     " --bootstrap"
     " --datadir=."
-    " --loose-innodb-buffer-pool-size=10M"
+    " --loose-innodb-buffer-pool-size=20M"
     "\""
     , mysqld_path, opt_verbose_bootstrap ? "--console" : "");
   return cmdline;
diff --git a/win/packaging/ca/CustomAction.cpp b/win/packaging/ca/CustomAction.cpp
index 328e73accb8..dbd0b36745f 100644
--- a/win/packaging/ca/CustomAction.cpp
+++ b/win/packaging/ca/CustomAction.cpp
@@ -664,6 +664,12 @@ unsigned long long GetMaxBufferSize(unsigned long long totalPhys)
 
 
 /*
+  Magic undocumented number for bufferpool minimum,
+  allows innodb to start also for all page sizes.
+*/
+static constexpr unsigned long long minBufferpoolMB= 20;
+
+/*
   Checks SERVICENAME, PORT and BUFFERSIZE parameters
 */
 extern "C" UINT  __stdcall CheckDatabaseProperties (MSIHANDLE hInstall)
@@ -791,34 +797,37 @@ extern "C" UINT  __stdcall CheckDatabaseProperties (MSIHANDLE hInstall)
      unsigned long long availableMemory=
        GetMaxBufferSize(memstatus.ullTotalPhys)/ONE_MB;
      swprintf_s(invalidValueMsg,
-        L"Invalid buffer pool size. Please use a number between 1 and %llu",
-         availableMemory);
-     if(BufferPoolSizeLen == 0 || BufferPoolSizeLen > 15)
+        L"Invalid buffer pool size. Please use a number between %llu and %llu",
+         minBufferpoolMB, availableMemory);
+     if (BufferPoolSizeLen == 0 || BufferPoolSizeLen > 15 || !BufferPoolSize[0])
      {
        ErrorMsg= invalidValueMsg;
        goto LExit;
      }
-     for (DWORD i=0; i < BufferPoolSizeLen && BufferPoolSize[BufferPoolSizeLen];
-       i++)
-     {
-       if(BufferPoolSize[i]< '0' || BufferPoolSize[i] > '9')
-       {
-         ErrorMsg= invalidValueMsg;
-         goto LExit;
-       }
-     }
+
      BufferPoolSize[BufferPoolSizeLen]=0;
      MsiSetPropertyW(hInstall, L"BUFFERPOOLSIZE", BufferPoolSize);
-     long long sz = _wtoi64(BufferPoolSize);
-     if(sz <= 0 || sz > (long long)availableMemory)
+     wchar_t *end;
+     unsigned long long sz = wcstoull(BufferPoolSize, &end, 10);
+     if (sz > availableMemory || sz < minBufferpoolMB || *end)
      {
-       if(sz > 0)
+       if (*end == 0)
        {
-         swprintf_s(invalidValueMsg,
-           L"Value for buffer pool size is too large."
-           L"Only approximately %llu MB is available for allocation."
-           L"Please use a number between 1 and %llu.",
-          availableMemory, availableMemory);
+         if(sz > availableMemory)
+         {
+           swprintf_s(invalidValueMsg,
+             L"Value for buffer pool size is too large."
+             L"Only approximately %llu MB is available for allocation."
+             L"Please use a number between %llu and %llu.",
+             availableMemory, minBufferpoolMB, availableMemory);
+         }
+         else if(sz < minBufferpoolMB)
+         {
+           swprintf_s(invalidValueMsg,
+             L"Value for buffer pool size is too small."
+             L"Please use a number between %llu and %llu.",
+             minBufferpoolMB, availableMemory);
+         }
        }
        ErrorMsg= invalidValueMsg;
        goto LExit;