Adding upstream version 1:10.11.6.upstream/1%10.11.6upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1176 insertions, 0 deletions

diff --git a/plugin/handler_socket/handlersocket/database.cpp b/plugin/handler_socket/handlersocket/database.cpp
new file mode 100644
index 00000000..db24e33a
--- /dev/null
+++ b/plugin/handler_socket/handlersocket/database.cpp
@@ -0,0 +1,1176 @@
+
+// vim:sw=2:ai
+
+/*
+ * Copyright (C) 2010 DeNA Co.,Ltd.. All rights reserved.
+ * See COPYRIGHT.txt for details.
+ */
+
+#include <my_global.h>
+#include <string.h>
+
+#include "database.hpp"
+#include "string_util.hpp"
+#include "escape.hpp"
+#include "mysql_incl.hpp"
+
+#define DBG_KEY(x)
+#define DBG_SHUT(x)
+#define DBG_LOCK(x)
+#define DBG_THR(x)
+#define DBG_CMP(x)
+#define DBG_FLD(x)
+#define DBG_FILTER(x)
+#define DBG_REFCNT(x)
+#define DBG_KEYLEN(x)
+#define DBG_DELETED
+
+/* status variables */
+unsigned long long int open_tables_count;
+unsigned long long int close_tables_count;
+unsigned long long int lock_tables_count;
+unsigned long long int unlock_tables_count;
+unsigned long long int index_exec_count;
+
+namespace dena {
+
+prep_stmt::prep_stmt()
+  : dbctx(0), table_id(static_cast<size_t>(-1)),
+    idxnum(static_cast<size_t>(-1))
+{
+}
+prep_stmt::prep_stmt(dbcontext_i *c, size_t tbl, size_t idx,
+  const fields_type& rf, const fields_type& ff)
+  : dbctx(c), table_id(tbl), idxnum(idx), ret_fields(rf), filter_fields(ff)
+{
+  if (dbctx) {
+    dbctx->table_addref(table_id);
+  }
+}
+prep_stmt::~prep_stmt()
+{
+  if (dbctx) {
+    dbctx->table_release(table_id);
+  }
+}
+
+prep_stmt::prep_stmt(const prep_stmt& x)
+  : dbctx(x.dbctx), table_id(x.table_id), idxnum(x.idxnum),
+  ret_fields(x.ret_fields), filter_fields(x.filter_fields)
+{
+  if (dbctx) {
+    dbctx->table_addref(table_id);
+  }
+}
+
+prep_stmt&
+prep_stmt::operator =(const prep_stmt& x)
+{
+  if (this != &x) {
+    if (dbctx) {
+      dbctx->table_release(table_id);
+    }
+    dbctx = x.dbctx;
+    table_id = x.table_id;
+    idxnum = x.idxnum;
+    ret_fields = x.ret_fields;
+    filter_fields = x.filter_fields;
+    if (dbctx) {
+      dbctx->table_addref(table_id);
+    }
+  }
+  return *this;
+}
+
+struct database : public database_i, private noncopyable {
+  database(const config& c);
+  virtual ~database();
+  virtual dbcontext_ptr create_context(bool for_write) volatile;
+  virtual void stop() volatile;
+  virtual const config& get_conf() const volatile;
+ public:
+  int child_running;
+ private:
+  config conf;
+};
+
+struct tablevec_entry {
+  TABLE *table;
+  size_t refcount;
+  bool modified;
+  tablevec_entry() : table(0), refcount(0), modified(false) { }
+};
+
+struct expr_user_lock : private noncopyable {
+  expr_user_lock(THD *thd, int timeout)
+    : lck_key(thd, "handlersocket_wr", 16, &my_charset_latin1),
+      lck_timeout(thd, timeout),
+      lck_func_get_lock(thd, &lck_key, &lck_timeout),
+      lck_func_release_lock(thd, &lck_key)
+  {
+    lck_key.fix_fields(thd, 0);
+    lck_timeout.fix_fields(thd, 0);
+    lck_func_get_lock.fix_fields(thd, 0);
+    lck_func_release_lock.fix_fields(thd, 0);
+  }
+  long long get_lock() {
+    return lck_func_get_lock.val_int();
+  }
+  long long release_lock() {
+    return lck_func_release_lock.val_int();
+  }
+ private:
+  Item_string lck_key;
+  Item_int lck_timeout;
+  Item_func_get_lock lck_func_get_lock;
+  Item_func_release_lock lck_func_release_lock;
+};
+
+struct dbcontext : public dbcontext_i, private noncopyable {
+  dbcontext(volatile database *d, bool for_write);
+  virtual ~dbcontext();
+  virtual void init_thread(const void *stack_botton,
+    volatile int& shutdown_flag);
+  virtual void term_thread();
+  virtual bool check_alive();
+  virtual void lock_tables_if();
+  virtual void unlock_tables_if();
+  virtual bool get_commit_error();
+  virtual void clear_error();
+  virtual void close_tables_if();
+  virtual void table_addref(size_t tbl_id);
+  virtual void table_release(size_t tbl_id);
+  virtual void cmd_open(dbcallback_i& cb, const cmd_open_args& args);
+  virtual void cmd_exec(dbcallback_i& cb, const cmd_exec_args& args);
+  virtual void set_statistics(size_t num_conns, size_t num_active);
+ private:
+  int set_thread_message(const char *fmt, ...)
+    __attribute__((format (printf, 2, 3)));
+  bool parse_fields(TABLE *const table, const char *str,
+    prep_stmt::fields_type& flds);
+  void cmd_insert_internal(dbcallback_i& cb, const prep_stmt& pst,
+    const string_ref *fvals, size_t fvalslen);
+  void cmd_sql_internal(dbcallback_i& cb, const prep_stmt& pst,
+    const string_ref *fvals, size_t fvalslen);
+  void cmd_find_internal(dbcallback_i& cb, const prep_stmt& pst,
+    ha_rkey_function find_flag, const cmd_exec_args& args);
+  size_t calc_filter_buf_size(TABLE *table, const prep_stmt& pst,
+    const record_filter *filters);
+  bool fill_filter_buf(TABLE *table, const prep_stmt& pst,
+    const record_filter *filters, uchar *filter_buf, size_t len);
+  int check_filter(dbcallback_i& cb, TABLE *table, const prep_stmt& pst,
+    const record_filter *filters, const uchar *filter_buf);
+  void resp_record(dbcallback_i& cb, TABLE *const table, const prep_stmt& pst);
+  void dump_record(dbcallback_i& cb, TABLE *const table, const prep_stmt& pst);
+  int modify_record(dbcallback_i& cb, TABLE *const table,
+    const prep_stmt& pst, const cmd_exec_args& args, char mod_op,
+    size_t& modified_count);
+ private:
+  typedef std::vector<tablevec_entry> table_vec_type;
+  typedef std::pair<std::string, std::string> table_name_type;
+  typedef std::map<table_name_type, size_t> table_map_type;
+ private:
+  volatile database *const dbref;
+  bool for_write_flag;
+  THD *thd;
+  MYSQL_LOCK *lock;
+  bool lock_failed;
+  std::auto_ptr<expr_user_lock> user_lock;
+  int user_level_lock_timeout;
+  bool user_level_lock_locked;
+  bool commit_error;
+  std::vector<char> info_message_buf;
+  table_vec_type table_vec;
+  table_map_type table_map;
+};
+
+database::database(const config& c)
+  : child_running(1), conf(c)
+{
+}
+
+database::~database() = default;
+
+dbcontext_ptr
+database::create_context(bool for_write) volatile
+{
+  return dbcontext_ptr(new dbcontext(this, for_write));
+}
+
+void
+database::stop() volatile
+{
+  child_running = false;
+}
+
+const config&
+database::get_conf() const volatile
+{
+  return const_cast<const config&>(conf);
+}
+
+database_ptr
+database_i::create(const config& conf)
+{
+  return database_ptr(new database(conf));
+}
+
+dbcontext::dbcontext(volatile database *d, bool for_write)
+  : dbref(d), for_write_flag(for_write), thd(0), lock(0), lock_failed(false),
+    user_level_lock_timeout(0), user_level_lock_locked(false),
+    commit_error(false)
+{
+  info_message_buf.resize(8192);
+  user_level_lock_timeout = d->get_conf().get_int("wrlock_timeout", 12);
+}
+
+dbcontext::~dbcontext() = default;
+
+namespace {
+
+int
+wait_server_to_start(THD *thd, volatile int& shutdown_flag)
+{
+  int r = 0;
+  DBG_SHUT(fprintf(stderr, "HNDSOCK wsts\n"));
+  pthread_mutex_lock(&LOCK_server_started);
+  while (!mysqld_server_started) {
+    timespec abstime;
+    set_timespec(abstime, 1);
+    pthread_cond_timedwait(&COND_server_started, &LOCK_server_started,
+      &abstime);
+    pthread_mutex_unlock(&LOCK_server_started);
+    pthread_mutex_lock(&thd->mysys_var->mutex);
+    killed_state st = thd->killed;
+    pthread_mutex_unlock(&thd->mysys_var->mutex);
+    DBG_SHUT(fprintf(stderr, "HNDSOCK wsts kst %d\n", (int)st));
+    pthread_mutex_lock(&LOCK_server_started);
+    if (st != NOT_KILLED) {
+      DBG_SHUT(fprintf(stderr, "HNDSOCK wsts kst %d break\n", (int)st));
+      r = -1;
+      break;
+    }
+    if (shutdown_flag) {
+      DBG_SHUT(fprintf(stderr, "HNDSOCK wsts kst shut break\n"));
+      r = -1;
+      break;
+    }
+  }
+  pthread_mutex_unlock(&LOCK_server_started);
+  DBG_SHUT(fprintf(stderr, "HNDSOCK wsts done\n"));
+  return r;
+}
+
+}; // namespace
+
+#define DENA_THR_OFFSETOF(fld) ((char *)(&thd->fld) - (char *)thd)
+
+void
+dbcontext::init_thread(const void *stack_bottom, volatile int& shutdown_flag)
+{
+  DBG_THR(fprintf(stderr, "HNDSOCK init thread\n"));
+  {
+    my_thread_init();
+    thd = new THD(0);
+    thd->thread_stack = (char *)stack_bottom;
+    DBG_THR(fprintf(stderr,
+      "thread_stack = %p sizeof(THD)=%zu sizeof(mtx)=%zu "
+      "O: %zu %zu %zu %zu %zu %zu %zu\n",
+      thd->thread_stack, sizeof(THD), sizeof(mysql_mutex_t),
+      DENA_THR_OFFSETOF(mdl_context),
+      DENA_THR_OFFSETOF(net),
+      DENA_THR_OFFSETOF(LOCK_thd_data),
+      DENA_THR_OFFSETOF(mysys_var),
+      DENA_THR_OFFSETOF(stmt_arena),
+      DENA_THR_OFFSETOF(limit_found_rows),
+      DENA_THR_OFFSETOF(locked_tables_list)));
+    thd->store_globals();
+    thd->system_thread = static_cast<enum_thread_type>(1<<30UL);
+    memset(&thd->net, 0, sizeof(thd->net));
+    if (for_write_flag) {
+      #if MYSQL_VERSION_ID >= 50505
+      thd->variables.option_bits |= OPTION_BIN_LOG;
+      #else
+      thd->options |= OPTION_BIN_LOG;
+      #endif
+      safeFree((char*) thd->db.str);
+      thd->db.str= my_strdup(PSI_NOT_INSTRUMENTED, "handlersocket", MYF(0));
+      thd->db.length= sizeof("handlersocket")-1;
+    }
+    thd->variables.option_bits |= OPTION_TABLE_LOCK;
+    set_current_thd(thd);
+    DBG_THR(fprintf(stderr, "HNDSOCK x0 %p\n", thd));
+  }
+  {
+    thd->thread_id = next_thread_id();
+    server_threads.insert(thd);
+  }
+
+  DBG_THR(fprintf(stderr, "HNDSOCK init thread wsts\n"));
+  wait_server_to_start(thd, shutdown_flag);
+  DBG_THR(fprintf(stderr, "HNDSOCK init thread done\n"));
+
+  thd_proc_info(thd, &info_message_buf[0]);
+  set_thread_message("hs:listening");
+  DBG_THR(fprintf(stderr, "HNDSOCK x1 %p\n", thd));
+
+  lex_start(thd);
+
+  user_lock.reset(new expr_user_lock(thd, user_level_lock_timeout));
+}
+
+int
+dbcontext::set_thread_message(const char *fmt, ...)
+{
+  va_list ap;
+  va_start(ap, fmt);
+  const int n = vsnprintf(&info_message_buf[0], info_message_buf.size(),
+    fmt, ap);
+  va_end(ap);
+  return n;
+}
+
+void
+dbcontext::term_thread()
+{
+  DBG_THR(fprintf(stderr, "HNDSOCK thread end %p\n", thd));
+  close_tables_if();
+  set_current_thd(nullptr);
+  {
+    delete thd;
+    thd = 0;
+    my_thread_end();
+  }
+}
+
+bool
+dbcontext::check_alive()
+{
+  pthread_mutex_lock(&thd->mysys_var->mutex);
+  killed_state st = thd->killed;
+  pthread_mutex_unlock(&thd->mysys_var->mutex);
+  DBG_SHUT(fprintf(stderr, "chk HNDSOCK kst %p %p %d %zu\n", thd, &thd->killed,
+    (int)st, sizeof(*thd)));
+  if (st != NOT_KILLED) {
+    DBG_SHUT(fprintf(stderr, "chk HNDSOCK kst %d break\n", (int)st));
+    return false;
+  }
+  return true;
+}
+
+void
+dbcontext::lock_tables_if()
+{
+  if (lock_failed) {
+    return;
+  }
+  if (for_write_flag && !user_level_lock_locked) {
+    if (user_lock->get_lock()) {
+      user_level_lock_locked = true;
+    } else {
+      lock_failed = true;
+      return;
+    }
+  }
+  if (lock == 0) {
+    const size_t num_max = table_vec.size();
+    TABLE **const tables = DENA_ALLOCA_ALLOCATE(TABLE *, num_max + 1);
+    size_t num_open = 0;
+    for (size_t i = 0; i < num_max; ++i) {
+      if (table_vec[i].refcount > 0) {
+	tables[num_open++] = table_vec[i].table;
+      }
+      table_vec[i].modified = false;
+    }
+    #if MYSQL_VERSION_ID >= 50505
+    lock = thd->lock = mysql_lock_tables(thd, &tables[0], num_open, 0);
+    #else
+    bool need_reopen= false;
+    lock = thd->lock = mysql_lock_tables(thd, &tables[0], num_open,
+      MYSQL_LOCK_NOTIFY_IF_NEED_REOPEN, &need_reopen);
+    #endif
+    statistic_increment(lock_tables_count, &LOCK_status);
+    thd_proc_info(thd, &info_message_buf[0]);
+    DENA_VERBOSE(100, fprintf(stderr, "HNDSOCK lock tables %p %p %zu %zu\n",
+      thd, lock, num_max, num_open));
+    if (lock == 0) {
+      lock_failed = true;
+      DENA_VERBOSE(10, fprintf(stderr, "HNDSOCK failed to lock tables %p\n",
+	thd));
+    }
+    if (for_write_flag) {
+      #if MYSQL_VERSION_ID >= 50505
+      thd->set_current_stmt_binlog_format_row();
+      #else
+      thd->current_stmt_binlog_row_based = 1;
+      #endif
+    }
+    DENA_ALLOCA_FREE(tables);
+  }
+  DBG_LOCK(fprintf(stderr, "HNDSOCK tblnum=%d\n", (int)tblnum));
+}
+
+void
+dbcontext::unlock_tables_if()
+{
+  if (lock != 0) {
+    DENA_VERBOSE(100, fprintf(stderr, "HNDSOCK unlock tables %p %p\n",
+      thd, thd->lock));
+    if (for_write_flag) {
+      for (size_t i = 0; i < table_vec.size(); ++i) {
+	if (table_vec[i].modified) {
+	  query_cache_invalidate3(thd, table_vec[i].table, 1);
+	  table_vec[i].table->file->ha_release_auto_increment();
+	}
+      }
+    }
+    {
+      bool suc = true;
+      #if MYSQL_VERSION_ID >= 50505
+      suc = (trans_commit_stmt(thd) == 0);
+      #else
+      suc = (ha_autocommit_or_rollback(thd, 0) == 0);
+      #endif
+      if (!suc) {
+	commit_error = true;
+	DENA_VERBOSE(10, fprintf(stderr,
+	  "HNDSOCK unlock tables: commit failed\n"));
+      }
+    }
+    mysql_unlock_tables(thd, lock);
+    lock = thd->lock = 0;
+    statistic_increment(unlock_tables_count, &LOCK_status);
+  }
+  if (user_level_lock_locked) {
+    if (user_lock->release_lock()) {
+      user_level_lock_locked = false;
+    }
+  }
+}
+
+bool
+dbcontext::get_commit_error()
+{
+  return commit_error;
+}
+
+void
+dbcontext::clear_error()
+{
+  lock_failed = false;
+  commit_error = false;
+}
+
+void
+dbcontext::close_tables_if()
+{
+  unlock_tables_if();
+  DENA_VERBOSE(100, fprintf(stderr, "HNDSOCK close tables\n"));
+  close_thread_tables(thd);
+  thd->mdl_context.release_transactional_locks(thd);
+  if (!table_vec.empty()) {
+    statistic_increment(close_tables_count, &LOCK_status);
+    table_vec.clear();
+    table_map.clear();
+  }
+}
+
+void
+dbcontext::table_addref(size_t tbl_id)
+{
+  table_vec[tbl_id].refcount += 1;
+  DBG_REFCNT(fprintf(stderr, "%p %zu %zu addref\n", this, tbl_id,
+    table_vec[tbl_id].refcount));
+}
+
+void
+dbcontext::table_release(size_t tbl_id)
+{
+  table_vec[tbl_id].refcount -= 1;
+  DBG_REFCNT(fprintf(stderr, "%p %zu %zu release\n", this, tbl_id,
+    table_vec[tbl_id].refcount));
+}
+
+void
+dbcontext::resp_record(dbcallback_i& cb, TABLE *const table,
+  const prep_stmt& pst)
+{
+  char rwpstr_buf[64];
+  String rwpstr(rwpstr_buf, sizeof(rwpstr_buf), &my_charset_bin);
+  const prep_stmt::fields_type& rf = pst.get_ret_fields();
+  const size_t n = rf.size();
+  for (size_t i = 0; i < n; ++i) {
+    uint32_t fn = rf[i];
+    Field *const fld = table->field[fn];
+    DBG_FLD(fprintf(stderr, "fld=%p %zu\n", fld, fn));
+    if (fld->is_null()) {
+      /* null */
+      cb.dbcb_resp_entry(0, 0);
+    } else {
+      fld->val_str(&rwpstr, &rwpstr);
+      const size_t len = rwpstr.length();
+      if (len != 0) {
+	/* non-empty */
+	cb.dbcb_resp_entry(rwpstr.ptr(), rwpstr.length());
+      } else {
+	/* empty */
+	static const char empty_str[] = "";
+	cb.dbcb_resp_entry(empty_str, 0);
+      }
+    }
+  }
+}
+
+void
+dbcontext::dump_record(dbcallback_i& cb, TABLE *const table,
+  const prep_stmt& pst)
+{
+  char rwpstr_buf[64];
+  String rwpstr(rwpstr_buf, sizeof(rwpstr_buf), &my_charset_bin);
+  const prep_stmt::fields_type& rf = pst.get_ret_fields();
+  const size_t n = rf.size();
+  for (size_t i = 0; i < n; ++i) {
+    uint32_t fn = rf[i];
+    Field *const fld = table->field[fn];
+    if (fld->is_null()) {
+      /* null */
+      fprintf(stderr, "NULL");
+    } else {
+      fld->val_str(&rwpstr, &rwpstr);
+      const std::string s(rwpstr.ptr(), rwpstr.length());
+      fprintf(stderr, "[%s]", s.c_str());
+    }
+  }
+  fprintf(stderr, "\n");
+}
+
+int
+dbcontext::modify_record(dbcallback_i& cb, TABLE *const table,
+  const prep_stmt& pst, const cmd_exec_args& args, char mod_op,
+  size_t& modified_count)
+{
+  if (mod_op == 'U') {
+    /* update */
+    handler *const hnd = table->file;
+    uchar *const buf = table->record[0];
+    store_record(table, record[1]);
+    const prep_stmt::fields_type& rf = pst.get_ret_fields();
+    const size_t n = rf.size();
+    for (size_t i = 0; i < n; ++i) {
+      const string_ref& nv = args.uvals[i];
+      uint32_t fn = rf[i];
+      Field *const fld = table->field[fn];
+      if (nv.begin() == 0) {
+	fld->set_null();
+      } else {
+	fld->set_notnull();
+	fld->store(nv.begin(), nv.size(), &my_charset_bin);
+      }
+    }
+    table_vec[pst.get_table_id()].modified = true;
+    const int r = hnd->ha_update_row(table->record[1], buf);
+    if (r != 0 && r != HA_ERR_RECORD_IS_THE_SAME) {
+      return r;
+    }
+    ++modified_count; /* TODO: HA_ERR_RECORD_IS_THE_SAME? */
+  } else if (mod_op == 'D') {
+    /* delete */
+    handler *const hnd = table->file;
+    table_vec[pst.get_table_id()].modified = true;
+    const int r = hnd->ha_delete_row(table->record[0]);
+    if (r != 0) {
+      return r;
+    }
+    ++modified_count;
+  } else if (mod_op == '+' || mod_op == '-') {
+    /* increment/decrement */
+    handler *const hnd = table->file;
+    uchar *const buf = table->record[0];
+    store_record(table, record[1]);
+    const prep_stmt::fields_type& rf = pst.get_ret_fields();
+    const size_t n = rf.size();
+    size_t i = 0;
+    for (i = 0; i < n; ++i) {
+      const string_ref& nv = args.uvals[i];
+      uint32_t fn = rf[i];
+      Field *const fld = table->field[fn];
+      if (fld->is_null() || nv.begin() == 0) {
+	continue;
+      }
+      const long long pval = fld->val_int();
+      const long long llv = atoll_nocheck(nv.begin(), nv.end());
+      /* TODO: llv == 0? */
+      long long nval = 0;
+      if (mod_op == '+') {
+	/* increment */
+	nval = pval + llv;
+      } else {
+	/* decrement */
+	nval = pval - llv;
+	if ((pval < 0 && nval > 0) || (pval > 0 && nval < 0)) {
+	  break; /* don't modify */
+	}
+      }
+      fld->store(nval, false);
+    }
+    if (i == n) {
+      /* modify */
+      table_vec[pst.get_table_id()].modified = true;
+      const int r = hnd->ha_update_row(table->record[1], buf);
+      if (r != 0 && r != HA_ERR_RECORD_IS_THE_SAME) {
+	return r;
+      }
+      ++modified_count;
+    }
+  }
+  return 0;
+}
+
+void
+dbcontext::cmd_insert_internal(dbcallback_i& cb, const prep_stmt& pst,
+  const string_ref *fvals, size_t fvalslen)
+{
+  if (!for_write_flag) {
+    return cb.dbcb_resp_short(2, "readonly");
+  }
+  lock_tables_if();
+  if (lock == 0) {
+    return cb.dbcb_resp_short(1, "lock_tables");
+  }
+  if (pst.get_table_id() >= table_vec.size()) {
+    return cb.dbcb_resp_short(2, "tblnum");
+  }
+  TABLE *const table = table_vec[pst.get_table_id()].table;
+  handler *const hnd = table->file;
+  uchar *const buf = table->record[0];
+  empty_record(table);
+  memset(buf, 0, table->s->null_bytes); /* clear null flags */
+  const prep_stmt::fields_type& rf = pst.get_ret_fields();
+  const size_t n = std::min(rf.size(), fvalslen);
+  for (size_t i = 0; i < n; ++i) {
+    uint32_t fn = rf[i];
+    Field *const fld = table->field[fn];
+    if (fvals[i].begin() == 0) {
+      fld->set_null();
+    } else {
+      fld->store(fvals[i].begin(), fvals[i].size(), &my_charset_bin);
+    }
+  }
+  table->next_number_field = table->found_next_number_field;
+    /* FIXME: test */
+  const int r = hnd->ha_write_row(buf);
+  const ulonglong insert_id = table->file->insert_id_for_cur_row;
+  table->next_number_field = 0;
+  table_vec[pst.get_table_id()].modified = true;
+  if (r == 0 && table->found_next_number_field != 0) {
+    return cb.dbcb_resp_short_num64(0, insert_id);
+  }
+  if (r != 0) {
+    return cb.dbcb_resp_short_num(1, r);
+  }
+  return cb.dbcb_resp_short(0, "");
+}
+
+void
+dbcontext::cmd_sql_internal(dbcallback_i& cb, const prep_stmt& pst,
+  const string_ref *fvals, size_t fvalslen)
+{
+  if (fvalslen < 1) {
+    return cb.dbcb_resp_short(2, "syntax");
+  }
+  return cb.dbcb_resp_short(2, "notimpl");
+}
+
+static size_t
+prepare_keybuf(const cmd_exec_args& args, uchar *key_buf, TABLE *table,
+  KEY& kinfo, size_t invalues_index)
+{
+  size_t kplen_sum = 0;
+  DBG_KEY(fprintf(stderr, "SLOW\n"));
+  for (size_t i = 0; i < args.kvalslen; ++i) {
+    const KEY_PART_INFO & kpt = kinfo.key_part[i];
+    string_ref kval = args.kvals[i];
+    if (args.invalues_keypart >= 0 &&
+      static_cast<size_t>(args.invalues_keypart) == i) {
+      kval = args.invalues[invalues_index];
+    }
+    if (kval.begin() == 0) {
+      kpt.field->set_null();
+    } else {
+      kpt.field->set_notnull();
+    }
+    kpt.field->store(kval.begin(), kval.size(), &my_charset_bin);
+    kplen_sum += kpt.store_length;
+    DBG_KEYLEN(fprintf(stderr, "l=%u sl=%zu\n", kpt.length,
+      kpt.store_length));
+  }
+  key_copy(key_buf, table->record[0], &kinfo, kplen_sum);
+  DBG_KEYLEN(fprintf(stderr, "sum=%zu flen=%u\n", kplen_sum,
+    kinfo.key_length));
+  return kplen_sum;
+}
+
+void
+dbcontext::cmd_find_internal(dbcallback_i& cb, const prep_stmt& pst,
+  ha_rkey_function find_flag, const cmd_exec_args& args)
+{
+  const bool debug_out = (verbose_level >= 100);
+  bool need_resp_record = true;
+  char mod_op = 0;
+  const string_ref& mod_op_str = args.mod_op;
+  if (mod_op_str.size() != 0) {
+    if (!for_write_flag) {
+      return cb.dbcb_resp_short(2, "readonly");
+    }
+    mod_op = mod_op_str.begin()[0];
+    need_resp_record = mod_op_str.size() > 1 && mod_op_str.begin()[1] == '?';
+    switch (mod_op) {
+    case 'U': /* update */
+    case 'D': /* delete */
+    case '+': /* increment */
+    case '-': /* decrement */
+      break;
+    default:
+      if (debug_out) {
+	fprintf(stderr, "unknown modop: %c\n", mod_op);
+      }
+      return cb.dbcb_resp_short(2, "modop");
+    }
+  }
+  lock_tables_if();
+  if (lock == 0) {
+    return cb.dbcb_resp_short(1, "lock_tables");
+  }
+  if (pst.get_table_id() >= table_vec.size()) {
+    return cb.dbcb_resp_short(2, "tblnum");
+  }
+  TABLE *const table = table_vec[pst.get_table_id()].table;
+  /* keys */
+  if (pst.get_idxnum() >= table->s->keys) {
+    return cb.dbcb_resp_short(2, "idxnum");
+  }
+  KEY& kinfo = table->key_info[pst.get_idxnum()];
+  if (args.kvalslen > kinfo.user_defined_key_parts) {
+    return cb.dbcb_resp_short(2, "kpnum");
+  }
+  uchar *const key_buf = DENA_ALLOCA_ALLOCATE(uchar, kinfo.key_length);
+  size_t invalues_idx = 0;
+  size_t kplen_sum = prepare_keybuf(args, key_buf, table, kinfo, invalues_idx);
+  /* filters */
+  uchar *filter_buf = 0;
+  if (args.filters != 0) {
+    const size_t filter_buf_len = calc_filter_buf_size(table, pst,
+      args.filters);
+    filter_buf = DENA_ALLOCA_ALLOCATE(uchar, filter_buf_len);
+    if (!fill_filter_buf(table, pst, args.filters, filter_buf,
+      filter_buf_len)) {
+      return cb.dbcb_resp_short(2, "filterblob");
+    }
+  }
+  /* handler */
+  table->read_set = &table->s->all_set;
+  handler *const hnd = table->file;
+  if (!for_write_flag) {
+    hnd->init_table_handle_for_HANDLER();
+  }
+  hnd->ha_index_or_rnd_end();
+  hnd->ha_index_init(pst.get_idxnum(), 1);
+  if (need_resp_record) {
+    cb.dbcb_resp_begin(pst.get_ret_fields().size());
+  }
+  const uint32_t limit = args.limit ? args.limit : 1;
+  uint32_t skip = args.skip;
+  size_t modified_count = 0;
+  int r = 0;
+  bool is_first = true;
+  for (uint32_t cnt = 0; cnt < limit + skip;) {
+    if (is_first) {
+      is_first = false;
+      const key_part_map kpm = (1U << args.kvalslen) - 1;
+      r = hnd->ha_index_read_map(table->record[0], key_buf, kpm, find_flag);
+    } else if (args.invalues_keypart >= 0) {
+      if (++invalues_idx >= args.invalueslen) {
+	break;
+      }
+      kplen_sum = prepare_keybuf(args, key_buf, table, kinfo, invalues_idx);
+      const key_part_map kpm = (1U << args.kvalslen) - 1;
+      r = hnd->ha_index_read_map(table->record[0], key_buf, kpm, find_flag);
+    } else {
+      switch (find_flag) {
+      case HA_READ_BEFORE_KEY:
+      case HA_READ_KEY_OR_PREV:
+	r = hnd->ha_index_prev(table->record[0]);
+	break;
+      case HA_READ_AFTER_KEY:
+      case HA_READ_KEY_OR_NEXT:
+	r = hnd->ha_index_next(table->record[0]);
+	break;
+      case HA_READ_KEY_EXACT:
+	r = hnd->ha_index_next_same(table->record[0], key_buf, kplen_sum);
+	break;
+      default:
+	r = HA_ERR_END_OF_FILE; /* to finish the loop */
+	break;
+      }
+    }
+    if (debug_out) {
+      fprintf(stderr, "r=%d\n", r);
+      if (r == 0 || r == HA_ERR_RECORD_DELETED) { 
+	dump_record(cb, table, pst);
+      }
+    }
+    int filter_res = 0;
+    if (r != 0) {
+      /* no-count */
+    } else if (args.filters != 0 && (filter_res = check_filter(cb, table, 
+      pst, args.filters, filter_buf)) != 0) {
+      if (filter_res < 0) {
+	break;
+      }
+    } else if (skip > 0) {
+      --skip;
+    } else {
+      /* hit */
+      if (need_resp_record) {
+	resp_record(cb, table, pst);
+      }
+      if (mod_op != 0) {
+	r = modify_record(cb, table, pst, args, mod_op, modified_count);
+      }
+      ++cnt;
+    }
+    if (args.invalues_keypart >= 0 && r == HA_ERR_KEY_NOT_FOUND) {
+      continue;
+    }
+    if (r != 0 && r != HA_ERR_RECORD_DELETED) {
+      break;
+    }
+  }
+  hnd->ha_index_or_rnd_end();
+  if (r != 0 && r != HA_ERR_RECORD_DELETED && r != HA_ERR_KEY_NOT_FOUND &&
+    r != HA_ERR_END_OF_FILE) {
+    /* failed */
+    if (need_resp_record) {
+      /* revert dbcb_resp_begin() and dbcb_resp_entry() */
+      cb.dbcb_resp_cancel();
+    }
+    cb.dbcb_resp_short_num(1, r);
+  } else {
+    /* succeeded */
+    if (need_resp_record) {
+      cb.dbcb_resp_end();
+    } else {
+      cb.dbcb_resp_short_num(0, modified_count);
+    }
+  }
+  DENA_ALLOCA_FREE(filter_buf);
+  DENA_ALLOCA_FREE(key_buf);
+}
+
+size_t
+dbcontext::calc_filter_buf_size(TABLE *table, const prep_stmt& pst,
+  const record_filter *filters)
+{
+  size_t filter_buf_len = 0;
+  for (const record_filter *f = filters; f->op.begin() != 0; ++f) {
+    if (f->val.begin() == 0) {
+      continue;
+    }
+    const uint32_t fn = pst.get_filter_fields()[f->ff_offset];
+    filter_buf_len += table->field[fn]->pack_length();
+  }
+  ++filter_buf_len;
+    /* Field_medium::cmp() calls uint3korr(), which may read 4 bytes.
+       Allocate 1 more byte for safety. */
+  return filter_buf_len;
+}
+
+bool
+dbcontext::fill_filter_buf(TABLE *table, const prep_stmt& pst,
+  const record_filter *filters, uchar *filter_buf, size_t len)
+{
+  memset(filter_buf, 0, len);
+  size_t pos = 0;
+  for (const record_filter *f = filters; f->op.begin() != 0; ++f) {
+    if (f->val.begin() == 0) {
+      continue;
+    }
+    const uint32_t fn = pst.get_filter_fields()[f->ff_offset];
+    Field *const fld = table->field[fn];
+    if ((fld->flags & BLOB_FLAG) != 0) {
+      return false;
+    }
+    fld->store(f->val.begin(), f->val.size(), &my_charset_bin);
+    const size_t packlen = fld->pack_length();
+    memcpy(filter_buf + pos, fld->ptr, packlen);
+    pos += packlen;
+  }
+  return true;
+}
+
+int
+dbcontext::check_filter(dbcallback_i& cb, TABLE *table, const prep_stmt& pst,
+  const record_filter *filters, const uchar *filter_buf)
+{
+  DBG_FILTER(fprintf(stderr, "check_filter\n"));
+  size_t pos = 0;
+  for (const record_filter *f = filters; f->op.begin() != 0; ++f) {
+    const string_ref& op = f->op;
+    const string_ref& val = f->val;
+    const uint32_t fn = pst.get_filter_fields()[f->ff_offset];
+    Field *const fld = table->field[fn];
+    const size_t packlen = fld->pack_length();
+    const uchar *const bval = filter_buf + pos;
+    int cv = 0;
+    if (fld->is_null()) {
+      cv = (val.begin() == 0) ? 0 : -1;
+    } else {
+      cv = (val.begin() == 0) ? 1 : fld->cmp(bval);
+    }
+    DBG_FILTER(fprintf(stderr, "check_filter cv=%d\n", cv));
+    bool cond = true;
+    if (op.size() == 1) {
+      switch (op.begin()[0]) {
+      case '>':
+	DBG_FILTER(fprintf(stderr, "check_filter op: >\n"));
+	cond = (cv > 0);
+	break;
+      case '<':
+	DBG_FILTER(fprintf(stderr, "check_filter op: <\n"));
+	cond = (cv < 0);
+	break;
+      case '=':
+	DBG_FILTER(fprintf(stderr, "check_filter op: =\n"));
+	cond = (cv == 0);
+	break;
+      default:
+	DBG_FILTER(fprintf(stderr, "check_filter op: unknown\n"));
+	cond = false; /* FIXME: error */
+	break;
+      }
+    } else if (op.size() == 2 && op.begin()[1] == '=') {
+      switch (op.begin()[0]) {
+      case '>':
+	DBG_FILTER(fprintf(stderr, "check_filter op: >=\n"));
+	cond = (cv >= 0);
+	break;
+      case '<':
+	DBG_FILTER(fprintf(stderr, "check_filter op: <=\n"));
+	cond = (cv <= 0);
+	break;
+      case '!':
+	DBG_FILTER(fprintf(stderr, "check_filter op: !=\n"));
+	cond = (cv != 0);
+	break;
+      default:
+	DBG_FILTER(fprintf(stderr, "check_filter op: unknown\n"));
+	cond = false; /* FIXME: error */
+	break;
+      }
+    }
+    DBG_FILTER(fprintf(stderr, "check_filter cond: %d\n", (int)cond));
+    if (!cond) {
+      return (f->filter_type == record_filter_type_skip) ? 1 : -1;
+    }
+    if (val.begin() != 0) {
+      pos += packlen;
+    }
+  }
+  return 0;
+}
+
+void
+dbcontext::cmd_open(dbcallback_i& cb, const cmd_open_args& arg)
+{
+  unlock_tables_if();
+  const table_name_type k = std::make_pair(std::string(arg.dbn),
+    std::string(arg.tbl));
+  const table_map_type::const_iterator iter = table_map.find(k);
+  uint32_t tblnum = 0;
+  if (iter != table_map.end()) {
+    tblnum = iter->second;
+    DBG_CMP(fprintf(stderr, "HNDSOCK k=%s tblnum=%d\n", k.c_str(),
+      (int)tblnum));
+  } else {
+    TABLE_LIST tables;
+    TABLE *table = 0;
+    bool refresh = true;
+    const thr_lock_type lock_type = for_write_flag ? TL_WRITE : TL_READ;
+    #if MYSQL_VERSION_ID >= 50505
+    LEX_CSTRING db_name=  { arg.dbn, strlen(arg.dbn) };
+    LEX_CSTRING tbl_name= { arg.tbl, strlen(arg.tbl) };
+    tables.init_one_table(&db_name, &tbl_name, 0, lock_type);
+    MDL_REQUEST_INIT(&tables.mdl_request, MDL_key::TABLE, arg.dbn, arg.tbl,
+      for_write_flag ? MDL_SHARED_WRITE : MDL_SHARED_READ, MDL_TRANSACTION);
+    Open_table_context ot_act(thd, 0);
+    if (!open_table(thd, &tables, &ot_act)) {
+      table = tables.table;
+    }
+    #else
+    tables.init_one_table(arg.dbn, arg.tbl, lock_type);
+    table = open_table(thd, &tables, thd->mem_root, &refresh,
+      OPEN_VIEW_NO_PARSE);
+    #endif
+    if (table == 0) {
+      DENA_VERBOSE(20, fprintf(stderr,
+	"HNDSOCK failed to open %p [%s] [%s] [%d]\n",
+	thd, arg.dbn, arg.tbl, static_cast<int>(refresh)));
+      return cb.dbcb_resp_short(1, "open_table");
+    }
+    statistic_increment(open_tables_count, &LOCK_status);
+    table->reginfo.lock_type = lock_type;
+    table->use_all_columns();
+    tblnum = table_vec.size();
+    tablevec_entry e;
+    e.table = table;
+    table_vec.push_back(e);
+    table_map[k] = tblnum;
+  }
+  size_t idxnum = static_cast<size_t>(-1);
+  if (arg.idx[0] >= '0' && arg.idx[0] <= '9') {
+    /* numeric */
+    TABLE *const table = table_vec[tblnum].table;
+    idxnum = atoi(arg.idx);
+    if (idxnum >= table->s->keys) {
+      return cb.dbcb_resp_short(2, "idxnum");
+    }
+  } else {
+    const char *const idx_name_to_open =
+      arg.idx[0]  == '\0' ? "PRIMARY" : arg.idx;
+    TABLE *const table = table_vec[tblnum].table;
+    for (uint i = 0; i < table->s->keys; ++i) {
+      KEY& kinfo = table->key_info[i];
+      if (strcmp(kinfo.name.str, idx_name_to_open) == 0) {
+	idxnum = i;
+	break;
+      }
+    }
+  }
+  if (idxnum == size_t(-1)) {
+    return cb.dbcb_resp_short(2, "idxnum");
+  }
+  prep_stmt::fields_type rf;
+  prep_stmt::fields_type ff;
+  if (!parse_fields(table_vec[tblnum].table, arg.retflds, rf)) {
+    return cb.dbcb_resp_short(2, "fld");
+  }
+  if (!parse_fields(table_vec[tblnum].table, arg.filflds, ff)) {
+    return cb.dbcb_resp_short(2, "fld");
+  }
+  prep_stmt p(this, tblnum, idxnum, rf, ff);
+  cb.dbcb_set_prep_stmt(arg.pst_id, p);
+  return cb.dbcb_resp_short(0, "");
+}
+
+bool
+dbcontext::parse_fields(TABLE *const table, const char *str,
+  prep_stmt::fields_type& flds)
+{
+  string_ref flds_sr(str, strlen(str));
+  std::vector<string_ref> fldnms;
+  if (flds_sr.size() != 0) {
+    split(',', flds_sr, fldnms);
+  }
+  for (size_t i = 0; i < fldnms.size(); ++i) {
+    Field **fld = 0;
+    size_t j = 0;
+    for (fld = table->field; *fld; ++fld, ++j) {
+      DBG_FLD(fprintf(stderr, "f %s\n", (*fld)->field_name.str));
+      string_ref fn((*fld)->field_name.str, (*fld)->field_name.length);
+      if (fn == fldnms[i]) {
+	break;
+      }
+    }
+    if (*fld == 0) {
+      DBG_FLD(fprintf(stderr, "UNKNOWN FLD %s [%s]\n", retflds,
+	std::string(fldnms[i].begin(), fldnms[i].size()).c_str()));
+      return false;
+    }
+    DBG_FLD(fprintf(stderr, "FLD %s %zu\n", (*fld)->field_name.str, j));
+    flds.push_back(j);
+  }
+  return true;
+}
+
+enum db_write_op {
+  db_write_op_none = 0,
+  db_write_op_insert = 1,
+  db_write_op_sql = 2,
+};
+
+void
+dbcontext::cmd_exec(dbcallback_i& cb, const cmd_exec_args& args)
+{
+  const prep_stmt& p = *args.pst;
+  if (p.get_table_id() == static_cast<size_t>(-1)) {
+    return cb.dbcb_resp_short(2, "stmtnum");
+  }
+  ha_rkey_function find_flag = HA_READ_KEY_EXACT;
+  db_write_op wrop = db_write_op_none;
+  if (args.op.size() == 1) {
+    switch (args.op.begin()[0]) {
+    case '=':
+      find_flag = HA_READ_KEY_EXACT;
+      break;
+    case '>':
+      find_flag = HA_READ_AFTER_KEY;
+      break;
+    case '<':
+      find_flag = HA_READ_BEFORE_KEY;
+      break;
+    case '+':
+      wrop = db_write_op_insert;
+      break;
+    case 'S':
+      wrop = db_write_op_sql;
+      break;
+    default:
+      return cb.dbcb_resp_short(2, "op");
+    }
+  } else if (args.op.size() == 2 && args.op.begin()[1] == '=') {
+    switch (args.op.begin()[0]) {
+    case '>':
+      find_flag = HA_READ_KEY_OR_NEXT;
+      break;
+    case '<':
+      find_flag = HA_READ_KEY_OR_PREV;
+      break;
+    default:
+      return cb.dbcb_resp_short(2, "op");
+    }
+  } else {
+    return cb.dbcb_resp_short(2, "op");
+  }
+  if (args.kvalslen <= 0) {
+    return cb.dbcb_resp_short(2, "klen");
+  }
+  switch (wrop) {
+  case db_write_op_none:
+    return cmd_find_internal(cb, p, find_flag, args);
+  case db_write_op_insert:
+    return cmd_insert_internal(cb, p, args.kvals, args.kvalslen);
+  case db_write_op_sql:
+    return cmd_sql_internal(cb, p, args.kvals, args.kvalslen);
+  }
+}
+
+void
+dbcontext::set_statistics(size_t num_conns, size_t num_active)
+{
+  if (for_write_flag) {
+    set_thread_message("handlersocket: mode=wr, %zu conns, %zu active",
+      num_conns, num_active);
+  } else {
+    set_thread_message("handlersocket: mode=rd, %zu conns, %zu active",
+      num_conns, num_active);
+  }
+  /*
+    Don't set message buf if it's already in use. This saves slow call to
+    thd_proc_info() (if profiling is enabled)
+  */
+  if (thd->proc_info != &info_message_buf[0])
+    thd_proc_info(thd, &info_message_buf[0]);
+}
+
+};
+