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  1. 23 Aug, 2006 1 commit
  2. 21 Aug, 2006 1 commit
    • dlenev@mockturtle.local's avatar
      Fix for bug#19403/12212 "Crash that happens during removing of database name · 8fb55ff0
      dlenev@mockturtle.local authored
      from cache" and #21216 "Simultaneous DROP TABLE and SHOW OPEN TABLES causes
      server to crash".
      
      Crash happened when one ran DROP DATABASE or SHOW OPEN TABLES statements
      while concurrently doing DROP TABLE (or RENAME TABLE, CREATE TABLE LIKE
      or any other command that takes name-lock) in other connection.
      
      This problem was caused by the fact that table placeholders which were
      added to table cache in order to obtain name-lock on table had
      TABLE_SHARE::db and table_name set to 0. Therefore they broke assumption
      that these members are non-0 for all tables in table cache on which some
      of our code relies.
      
      The fix sets these members for such placeholders to appropriate value making
      this assumption true again. As attempt to avoid such problems in future
      we introduce auxiliary TABLE_SHARE::set_table_cache_key() methods which
      should be used when one wants to set TABLE_SHARE::table_cache_key and which
      ensure that TABLE_SHARE::table_name/db are set properly.
      
      Test cases for these bugs were added to 5.0 test-suite (with 5.0-specific
      fix for bug #21216).
      8fb55ff0
  3. 01 Aug, 2006 1 commit
  4. 31 Jul, 2006 1 commit
  5. 28 Jul, 2006 2 commits
  6. 27 Jul, 2006 1 commit
    • kroki/tomash@moonlight.intranet's avatar
      BUG#21206: memory corruption when too many cursors are opened at once · 1917a992
      kroki/tomash@moonlight.intranet authored
      Too many cursors (more than 1024) could lead to memory corruption.
      This affects both, stored routines and C API cursors, and the
      threshold is per-server, not per-connection.  Similarly, the
      corruption could happen when the server was under heavy load
      (executing more than 1024 simultaneous complex queries), and this is
      the reason why this bug is fixed in 4.1, which doesn't support
      cursors.
      
      The corruption was caused by a bug in the temporary tables code, when
      an attempt to create a table could lead to a write beyond allocated
      space.  Note, that only internal tables were affected (the tables
      created internally by the server to resolve the query), not tables
      created with CREATE TEMPORARY TABLE.  Another pre-condition for the
      bug is TRUE value of --temp-pool startup option, which, however, is a
      default.
      
      The cause of a bug was that random memory was overwritten in
      bitmap_set_next() due to out-of-bound memory access.
      1917a992
  7. 26 Jul, 2006 4 commits
    • evgen@moonbone.local's avatar
      item_func.h, item_func.cc, sql_select.cc, item.h: · b7ade8e4
      evgen@moonbone.local authored
        Post review changes for bug#19862.
      b7ade8e4
    • gkodinov/kgeorge@macbook.gmz's avatar
      * Bug #20792: Incorrect results from aggregate subquery · 565d4959
      gkodinov/kgeorge@macbook.gmz authored
      When processing aggregate functions all tables values are reset
      to NULLs at the end of each group. 
      When doing that if there are no rows found for a group
      the const tables must not be reset as they are not recalculated 
      by do_select()/sub_select() for each group.
      565d4959
    • kroki/tomash@moonlight.intranet's avatar
      BUG#21206: memory corruption when too many cursors are opened at once · 4e845ccc
      kroki/tomash@moonlight.intranet authored
      Too many cursors (more than 1024) could lead to memory corruption.
      This affects both, stored routines and C API cursors, and the
      threshold is per-server, not per-connection.  Similarly, the
      corruption could happen when the server was under heavy load
      (executing more than 1024 simultaneous complex queries), and this is
      the reason why this bug is fixed in 4.1, which doesn't support
      cursors.
      
      The corruption was caused by a bug in the temporary tables code, when
      an attempt to create a table could lead to a write beyond allocated
      space.  Note, that only internal tables were affected (the tables
      created internally by the server to resolve the query), not tables
      created with CREATE TEMPORARY TABLE.  Another pre-condition for the
      bug is TRUE value of --temp-pool startup option, which, however, is a
      default.
      
      The cause of a bug was that random memory was overwritten in
      bitmap_set_next() due to out-of-bound memory access.
      4e845ccc
    • gkodinov/kgeorge@macbook.gmz's avatar
      Bug #21019: First result of SELECT COUNT(*) different than consecutive runs · 6766cfcd
      gkodinov/kgeorge@macbook.gmz authored
       When optimizing conditions like 'a = <some_val> OR a IS NULL' so that they're
       united into a single condition on the key and checked together the server must 
       check which value is the NULL value in a correct way : not only using ->is_null 
       but also check if the expression doesn't depend on any tables referenced in the 
       current statement. 
       This additional check must be performed because that optimization takes place 
       before the actual execution of the statement, so if the field was initialized 
       to NULL from a previous statement the optimization would be applied incorrectly.
      6766cfcd
  8. 25 Jul, 2006 3 commits
    • timour/timka@lamia.home's avatar
      Fix for BUG#20954: avg(keyval) retuns 0.38 but max(keyval) returns an empty set · 86ae2f3b
      timour/timka@lamia.home authored
      The problem was in that opt_sum_query() replaced MIN/MAX functions
      with the corresponding constant found in a key, but due to imprecise
      representation of float numbers, when evaluating the where clause,
      this comparison failed.
      
      When MIN/MAX optimization detects that all tables can be removed,
      also remove all conjuncts in a where clause that refer to these
      tables. As a result of this fix, these conditions are not evaluated
      twice, and in the case of float number comparisons we do not discard
      result rows due to imprecise float representation.
      
      As a side-effect this fix also corrects an unnoticed problem in
      bug 12882.
      86ae2f3b
    • evgen@moonbone.local's avatar
      Fixed bug#19862: Sort with filesort by function evaluates function twice · 4ee2e07c
      evgen@moonbone.local authored
      When there is no index defined filesort is used to sort the result of a
      query. If there is a function in the select list and the result set should be
      ordered by it's value then this function will be evaluated twice. First time to
      get the value of the sort key and second time to send its value to a user.
      This happens because filesort when sorts a table remembers only values of its
      fields but not values of functions.
      All functions are affected. But taking into account that SP and UDF functions
      can be both expensive and non-deterministic a temporary table should be used 
      to store their results and then sort it to avoid twice SP evaluation and to 
      get a correct result.
      
      If an expression referenced in an ORDER clause contains a SP or UDF 
      function, force the use of a temporary table.
      
      A new Item_processor function called func_type_checker_processor is added
      to check whether the expression contains a function of a particular type.
      4ee2e07c
    • gkodinov/kgeorge@macbook.gmz's avatar
      Bug#16712: group_concat returns odd srting insead of intended result · 9380bb83
      gkodinov/kgeorge@macbook.gmz authored
        when calculating GROUP_CONCAT all blob fields are transformed
        to varchar when making the temp table.
        However a varchar has at max 2 bytes for length. 
        This fix makes the conversion only for blobs whose max length 
        is below that limit. 
        Otherwise blob field is created by make_string_field() call.
      9380bb83
  9. 21 Jul, 2006 2 commits
  10. 15 Jul, 2006 1 commit
    • igor@olga.mysql.com's avatar
      Fixed bug #20519. · 4de3186a
      igor@olga.mysql.com authored
      The bug was due to a loss happened during a refactoring made
      on May 30 2005 that modified the function JOIN::reinit.
      As a result of it for any subquery the value of offset_limit_cnt
      was not restored for the following executions. Yet the first 
      execution of the subquery made it equal to 0.
      The fix restores this value in the function JOIN::reinit.  
      4de3186a
  11. 14 Jul, 2006 1 commit
    • igor@olga.mysql.com's avatar
      Fixed bug #19714. · f6080640
      igor@olga.mysql.com authored
      DESCRIBE returned the type BIGINT for a column of a view if the column
      was specified by an expression over values of the type INT.
          
      E.g. for the view defined as follows:
        CREATE VIEW v1 SELECT COALESCE(f1,f2) FROM t1
      DESCRIBE returned type BIGINT for the only column of the view if f1,f2 are
      columns of the INT type.
      At the same time DESCRIBE returned type INT for the only column of the table
      defined by the statement:
        CREATE TABLE t2 SELECT COALESCE(f1,f2) FROM t1.
          
      This inconsistency was removed by the patch.
      
      Now the code chooses between INT/BIGINT depending on the
      precision of the aggregated column type.
       
      Thus both DESCRIBE commands above returns type INT for v1 and t2.
       
      f6080640
  12. 12 Jul, 2006 1 commit
  13. 11 Jul, 2006 1 commit
    • evgen@moonbone.local's avatar
      Fixed bug#18503: Queries with a quantified subquery returning empty set · 8ffda481
      evgen@moonbone.local authored
      may return a wrong result.
      
      An Item_sum_hybrid object has the was_values flag which indicates whether any
      values were added to the sum function. By default it is set to true and reset
      to false on any no_rows_in_result() call. This method is called only in
      return_zero_rows() function. An ALL/ANY subquery can be optimized by MIN/MAX
      optimization. The was_values flag is used to indicate whether the subquery
      has returned at least one row. This bug occurs because return_zero_rows() is
      called only when we know that the select will return zero rows before
      starting any scans but often such information is not known.
      In the reported case the return_zero_rows() function is not called and
      the was_values flag is not reset to false and yet the subquery return no rows
      Item_func_not_all and Item_func_nop_all functions return a wrong
      comparison result.
      
      The end_send_group() function now calls no_rows_in_result() for each item
      in the fields_list if there is no rows were found for the (sub)query.
      8ffda481
  14. 10 Jul, 2006 1 commit
    • gkodinov/kgeorge@mysql.com/rakia.(none)'s avatar
      BUG#14553: NULL in WHERE resets LAST_INSERT_ID · 2c9f5cc7
      To make MySQL compatible with some ODBC applications, you can find
      the AUTO_INCREMENT value for the last inserted row with the following query:
       SELECT * FROM tbl_name WHERE auto_col IS NULL.
      This is done with a special code that replaces 'auto_col IS NULL' with
      'auto_col = LAST_INSERT_ID'.
      However this also resets the LAST_INSERT_ID to 0 as it uses it for a flag
      so as to ensure that only the first SELECT ... WHERE auto_col IS NULL
      after an INSERT has this special behaviour.
      In order to avoid resetting the LAST_INSERT_ID a special flag is introduced
      in the THD class. This flag is used to restrict the second and subsequent
      SELECTs instead of LAST_INSERT_ID.
      2c9f5cc7
  15. 09 Jul, 2006 1 commit
    • guilhem@gbichot3.local's avatar
      WL#3146 "less locking in auto_increment": · 0594e1b8
      guilhem@gbichot3.local authored
      this is a cleanup patch for our current auto_increment handling:
      new names for auto_increment variables in THD, new methods to manipulate them
      (see sql_class.h), some move into handler::, causing less backup/restore
      work when executing substatements. 
      This makes the logic hopefully clearer, less work is is needed in
      mysql_insert().
      By cleaning up, using different variables for different purposes (instead
      of one for 3 things...), we fix those bugs, which someone may want to fix
      in 5.0 too:
      BUG#20339 "stored procedure using LAST_INSERT_ID() does not replicate
      statement-based"
      BUG#20341 "stored function inserting into one auto_increment puts bad
      data in slave"
      BUG#19243 "wrong LAST_INSERT_ID() after ON DUPLICATE KEY UPDATE"
      (now if a row is updated, LAST_INSERT_ID() will return its id)
      and re-fixes:
      BUG#6880 "LAST_INSERT_ID() value changes during multi-row INSERT"
      (already fixed differently by Ramil in 4.1)
      Test of documented behaviour of mysql_insert_id() (there was no test).
      The behaviour changes introduced are:
      - LAST_INSERT_ID() now returns "the first autogenerated auto_increment value
      successfully inserted", instead of "the first autogenerated auto_increment
      value if any row was successfully inserted", see auto_increment.test.
      Same for mysql_insert_id(), see mysql_client_test.c.
      - LAST_INSERT_ID() returns the id of the updated row if ON DUPLICATE KEY
      UPDATE, see auto_increment.test. Same for mysql_insert_id(), see
      mysql_client_test.c.
      - LAST_INSERT_ID() does not change if no autogenerated value was successfully 
      inserted (it used to then be 0), see auto_increment.test.
      - if in INSERT SELECT no autogenerated value was successfully inserted,
      mysql_insert_id() now returns the id of the last inserted row (it already
      did this for INSERT VALUES), see mysql_client_test.c.
      - if INSERT SELECT uses LAST_INSERT_ID(X), mysql_insert_id() now returns X
      (it already did this for INSERT VALUES), see mysql_client_test.c.
      - NDB now behaves like other engines wrt SET INSERT_ID: with INSERT IGNORE,
      the id passed in SET INSERT_ID is re-used until a row succeeds; SET INSERT_ID
      influences not only the first row now.
      
      Additionally, when unlocking a table we check that the thread is not keeping
      a next_insert_id (as the table is unlocked that id is potentially out-of-date);
      forgetting about this next_insert_id is done in a new
      handler::ha_release_auto_increment().
      
      Finally we prepare for engines capable of reserving finite-length intervals
      of auto_increment values: we store such intervals in THD. The next step
      (to be done by the replication team in 5.1) is to read those intervals from
      THD and actually store them in the statement-based binary log. NDB
      will be a good engine to test that.
      0594e1b8
  16. 01 Jul, 2006 1 commit
  17. 30 Jun, 2006 1 commit
  18. 28 Jun, 2006 1 commit
  19. 27 Jun, 2006 2 commits
    • kroki@mysql.com's avatar
      Bug#17203: "sql_no_cache sql_cache" in views created from prepared statement · 08f192f8
      kroki@mysql.com authored
      The problem was that we restored SQL_CACHE, SQL_NO_CACHE flags in SELECT
      statement from internal structures based on value set later at runtime, not
      the original value set by the user.
      
      The solution is to remember that original value.
      08f192f8
    • gkodinov@mysql.com's avatar
      Bug #16458: Simple SELECT FOR UPDATE causes "Result Set not updatable" error · 9ec681ef
      gkodinov@mysql.com authored
      'SELECT DISTINCT a,b FROM t1' should not use temp table if there is unique 
      index (or primary key) on a.
      There are a number of other similar cases that can be calculated without the
      use of a temp table : multi-part unique indexes, primary keys or using GROUP BY 
      instead of DISTINCT.
      When a GROUP BY/DISTINCT clause contains all key parts of a unique
      index, then it is guaranteed that the fields of the clause will be
      unique, therefore we can optimize away GROUP BY/DISTINCT altogether.
      This optimization has two effects:
      * there is no need to create a temporary table to compute the
         GROUP/DISTINCT operation (or the temporary table will be smaller if only GROUP 
         is removed and DISTINCT stays or if DISTINCT is removed and GROUP BY stays)
      * this causes the statement in effect to become updatable in Connector/Java
      because the result set columns will be direct reference to the primary key of 
      the table (instead to the temporary table that it currently references). 
      
      Implemented a check that will optimize away GROUP BY/DISTINCT for queries like 
      the above.
      Currently it will work only for single non-constant table in the FROM clause.
      9ec681ef
  20. 26 Jun, 2006 1 commit
    • ingo@mysql.com's avatar
      Bug#16218 - Crash on insert delayed · 8728fbbc
      ingo@mysql.com authored
      Bug#17294 - INSERT DELAYED puting an \n before data
      Bug#16611 - INSERT DELAYED corrupts data
      Bug#13707 - Server crash with INSERT DELAYED on MyISAM table
      Combined as Bug#16218.
      
      INSERT DELAYED crashed in 5.0 on a table with a varchar that 
      could be NULL and was created pre-5.0 (Bugs 16218 and 13707).
      INSERT DELAYED corrupted data in 5.0 on a table with varchar 
      fields that was created pre-5.0 (Bugs 17294 and 16611).
      
      In case of INSERT DELAYED the open table is copied from the
      delayed insert thread to be able to create a record for the 
      queue. When copying the fields, a method was used that did 
      convert old varchar to new varchar fields and did not set up 
      some pointers into the record buffer of the table.
      
      The field conversion was guilty for the misinterpretation of 
      the record contents by the delayed insert thread. The wrong
      pointer setup was guilty for the crashes.
      
      For Bug 13707 (Server crash with INSERT DELAYED on MyISAM table)
      I fixed the above mentioned method to set up one of the pointers.
      For Bug 16218 I set up the other pointers too.
      
      But when looking at the corruptions I got aware that converting
      the field type was totally wrong for INSERT DELAYED. The copied
      table is used to create a record that is to be sent to the
      delayed insert thread. Of course it can interpret the record
      correctly only if all field types are the same in both table
      objects.
      
      So I revoked the fix for Bug 13707 and changed the new_field() 
      method so that it can suppress conversions.
      
      No test case as this is a migration problem. One needs to
      create a table with 4.x and use it with 5.x. I added two
      test scripts to the bug report.
      8728fbbc
  21. 22 Jun, 2006 1 commit
  22. 20 Jun, 2006 4 commits
  23. 19 Jun, 2006 1 commit
    • gkodinov@mysql.com's avatar
      * Bug #9676: INSERT INTO x SELECT .. FROM x LIMIT 1; slows down with big · c5ed7a87
      gkodinov@mysql.com authored
                    tables
      Currently in INSERT ... SELECT ... LIMIT ... the compiler uses a 
      temporary table to store the results of SELECT ... LIMIT .. and then
      uses that table as a source for INSERT. The problem is that in some cases
      it actually skips the LIMIT clause in doing that and materializes the 
      whole SELECT result set regardless of the LIMIT.
      This fix is limiting the process of filling up the temp table with only 
      that much rows that will be actually used by propagating the LIMIT value.
      c5ed7a87
  24. 05 Jun, 2006 2 commits
  25. 04 Jun, 2006 1 commit
    • monty@mysql.com's avatar
      This changeset is largely a handler cleanup changeset (WL#3281), but includes... · 74cc73d4
      monty@mysql.com authored
      This changeset is largely a handler cleanup changeset (WL#3281), but includes fixes and cleanups that was found necessary while testing the handler changes
      
      Changes that requires code changes in other code of other storage engines.
      (Note that all changes are very straightforward and one should find all issues
      by compiling a --debug build and fixing all compiler errors and all
      asserts in field.cc while running the test suite),
      
      - New optional handler function introduced: reset()
        This is called after every DML statement to make it easy for a handler to
        statement specific cleanups.
        (The only case it's not called is if force the file to be closed)
      
      - handler::extra(HA_EXTRA_RESET) is removed. Code that was there before
        should be moved to handler::reset()
      
      - table->read_set contains a bitmap over all columns that are needed
        in the query.  read_row() and similar functions only needs to read these
        columns
      - table->write_set contains a bitmap over all columns that will be updated
        in the query. write_row() and update_row() only needs to update these
        columns.
        The above bitmaps should now be up to date in all context
        (including ALTER TABLE, filesort()).
      
        The handler is informed of any changes to the bitmap after
        fix_fields() by calling the virtual function
        handler::column_bitmaps_signal(). If the handler does caching of
        these bitmaps (instead of using table->read_set, table->write_set),
        it should redo the caching in this code. as the signal() may be sent
        several times, it's probably best to set a variable in the signal
        and redo the caching on read_row() / write_row() if the variable was
        set.
      
      - Removed the read_set and write_set bitmap objects from the handler class
      
      - Removed all column bit handling functions from the handler class.
        (Now one instead uses the normal bitmap functions in my_bitmap.c instead
        of handler dedicated bitmap functions)
      
      - field->query_id is removed. One should instead instead check
        table->read_set and table->write_set if a field is used in the query.
      
      - handler::extra(HA_EXTRA_RETRIVE_ALL_COLS) and
        handler::extra(HA_EXTRA_RETRIEVE_PRIMARY_KEY) are removed. One should now
        instead use table->read_set to check for which columns to retrieve.
      
      - If a handler needs to call Field->val() or Field->store() on columns
        that are not used in the query, one should install a temporary
        all-columns-used map while doing so. For this, we provide the following
        functions:
      
        my_bitmap_map *old_map= dbug_tmp_use_all_columns(table, table->read_set);
        field->val();
        dbug_tmp_restore_column_map(table->read_set, old_map);
      
        and similar for the write map:
      
        my_bitmap_map *old_map= dbug_tmp_use_all_columns(table, table->write_set);
        field->val();
        dbug_tmp_restore_column_map(table->write_set, old_map);
      
        If this is not done, you will sooner or later hit a DBUG_ASSERT
        in the field store() / val() functions.
        (For not DBUG binaries, the dbug_tmp_restore_column_map() and
        dbug_tmp_restore_column_map() are inline dummy functions and should
        be optimized away be the compiler).
      
      - If one needs to temporary set the column map for all binaries (and not
        just to avoid the DBUG_ASSERT() in the Field::store() / Field::val()
        methods) one should use the functions tmp_use_all_columns() and
        tmp_restore_column_map() instead of the above dbug_ variants.
      
      - All 'status' fields in the handler base class (like records,
        data_file_length etc) are now stored in a 'stats' struct. This makes
        it easier to know what status variables are provided by the base
        handler.  This requires some trivial variable names in the extra()
        function.
      
      - New virtual function handler::records().  This is called to optimize
        COUNT(*) if (handler::table_flags() & HA_HAS_RECORDS()) is true.
        (stats.records is not supposed to be an exact value. It's only has to
        be 'reasonable enough' for the optimizer to be able to choose a good
        optimization path).
      
      - Non virtual handler::init() function added for caching of virtual
        constants from engine.
      
      - Removed has_transactions() virtual method. Now one should instead return
        HA_NO_TRANSACTIONS in table_flags() if the table handler DOES NOT support
        transactions.
      
      - The 'xxxx_create_handler()' function now has a MEM_ROOT_root argument
        that is to be used with 'new handler_name()' to allocate the handler
        in the right area.  The xxxx_create_handler() function is also
        responsible for any initialization of the object before returning.
      
        For example, one should change:
      
        static handler *myisam_create_handler(TABLE_SHARE *table)
        {
          return new ha_myisam(table);
        }
      
        ->
      
        static handler *myisam_create_handler(TABLE_SHARE *table, MEM_ROOT *mem_root)
        {
          return new (mem_root) ha_myisam(table);
        }
      
      - New optional virtual function: use_hidden_primary_key().
        This is called in case of an update/delete when
        (table_flags() and HA_PRIMARY_KEY_REQUIRED_FOR_DELETE) is defined
        but we don't have a primary key. This allows the handler to take precisions
        in remembering any hidden primary key to able to update/delete any
        found row. The default handler marks all columns to be read.
      
      - handler::table_flags() now returns a ulonglong (to allow for more flags).
      
      - New/changed table_flags()
        - HA_HAS_RECORDS	    Set if ::records() is supported
        - HA_NO_TRANSACTIONS	    Set if engine doesn't support transactions
        - HA_PRIMARY_KEY_REQUIRED_FOR_DELETE
                                  Set if we should mark all primary key columns for
      			    read when reading rows as part of a DELETE
      			    statement. If there is no primary key,
      			    all columns are marked for read.
        - HA_PARTIAL_COLUMN_READ  Set if engine will not read all columns in some
      			    cases (based on table->read_set)
       - HA_PRIMARY_KEY_ALLOW_RANDOM_ACCESS
         			    Renamed to HA_PRIMARY_KEY_REQUIRED_FOR_POSITION.
       - HA_DUPP_POS              Renamed to HA_DUPLICATE_POS
       - HA_REQUIRES_KEY_COLUMNS_FOR_DELETE
      			    Set this if we should mark ALL key columns for
      			    read when when reading rows as part of a DELETE
      			    statement. In case of an update we will mark
      			    all keys for read for which key part changed
      			    value.
        - HA_STATS_RECORDS_IS_EXACT
      			     Set this if stats.records is exact.
      			     (This saves us some extra records() calls
      			     when optimizing COUNT(*))
      			    
      
      - Removed table_flags()
        - HA_NOT_EXACT_COUNT     Now one should instead use HA_HAS_RECORDS if
      			   handler::records() gives an exact count() and
      			   HA_STATS_RECORDS_IS_EXACT if stats.records is exact.
        - HA_READ_RND_SAME	   Removed (no one supported this one)
      
      - Removed not needed functions ha_retrieve_all_cols() and ha_retrieve_all_pk()
      
      - Renamed handler::dupp_pos to handler::dup_pos
      
      - Removed not used variable handler::sortkey
      
      
      Upper level handler changes:
      
      - ha_reset() now does some overall checks and calls ::reset()
      - ha_table_flags() added. This is a cached version of table_flags(). The
        cache is updated on engine creation time and updated on open.
      
      
      MySQL level changes (not obvious from the above):
      
      - DBUG_ASSERT() added to check that column usage matches what is set
        in the column usage bit maps. (This found a LOT of bugs in current
        column marking code).
      
      - In 5.1 before, all used columns was marked in read_set and only updated
        columns was marked in write_set. Now we only mark columns for which we
        need a value in read_set.
      
      - Column bitmaps are created in open_binary_frm() and open_table_from_share().
        (Before this was in table.cc)
      
      - handler::table_flags() calls are replaced with handler::ha_table_flags()
      
      - For calling field->val() you must have the corresponding bit set in
        table->read_set. For calling field->store() you must have the
        corresponding bit set in table->write_set. (There are asserts in
        all store()/val() functions to catch wrong usage)
      
      - thd->set_query_id is renamed to thd->mark_used_columns and instead
        of setting this to an integer value, this has now the values:
        MARK_COLUMNS_NONE, MARK_COLUMNS_READ, MARK_COLUMNS_WRITE
        Changed also all variables named 'set_query_id' to mark_used_columns.
      
      - In filesort() we now inform the handler of exactly which columns are needed
        doing the sort and choosing the rows.
      
      - The TABLE_SHARE object has a 'all_set' column bitmap one can use
        when one needs a column bitmap with all columns set.
        (This is used for table->use_all_columns() and other places)
      
      - The TABLE object has 3 column bitmaps:
        - def_read_set     Default bitmap for columns to be read
        - def_write_set    Default bitmap for columns to be written
        - tmp_set          Can be used as a temporary bitmap when needed.
        The table object has also two pointer to bitmaps read_set and write_set
        that the handler should use to find out which columns are used in which way.
      
      - count() optimization now calls handler::records() instead of using
        handler->stats.records (if (table_flags() & HA_HAS_RECORDS) is true).
      
      - Added extra argument to Item::walk() to indicate if we should also
        traverse sub queries.
      
      - Added TABLE parameter to cp_buffer_from_ref()
      
      - Don't close tables created with CREATE ... SELECT but keep them in
        the table cache. (Faster usage of newly created tables).
      
      
      New interfaces:
      
      - table->clear_column_bitmaps() to initialize the bitmaps for tables
        at start of new statements.
      
      - table->column_bitmaps_set() to set up new column bitmaps and signal
        the handler about this.
      
      - table->column_bitmaps_set_no_signal() for some few cases where we need
        to setup new column bitmaps but don't signal the handler (as the handler
        has already been signaled about these before). Used for the momement
        only in opt_range.cc when doing ROR scans.
      
      - table->use_all_columns() to install a bitmap where all columns are marked
        as use in the read and the write set.
      
      - table->default_column_bitmaps() to install the normal read and write
        column bitmaps, but not signaling the handler about this.
        This is mainly used when creating TABLE instances.
      
      - table->mark_columns_needed_for_delete(),
        table->mark_columns_needed_for_delete() and
        table->mark_columns_needed_for_insert() to allow us to put additional
        columns in column usage maps if handler so requires.
        (The handler indicates what it neads in handler->table_flags())
      
      - table->prepare_for_position() to allow us to tell handler that it
        needs to read primary key parts to be able to store them in
        future table->position() calls.
        (This replaces the table->file->ha_retrieve_all_pk function)
      
      - table->mark_auto_increment_column() to tell handler are going to update
        columns part of any auto_increment key.
      
      - table->mark_columns_used_by_index() to mark all columns that is part of
        an index.  It will also send extra(HA_EXTRA_KEYREAD) to handler to allow
        it to quickly know that it only needs to read colums that are part
        of the key.  (The handler can also use the column map for detecting this,
        but simpler/faster handler can just monitor the extra() call).
      
      - table->mark_columns_used_by_index_no_reset() to in addition to other columns,
        also mark all columns that is used by the given key.
      
      - table->restore_column_maps_after_mark_index() to restore to default
        column maps after a call to table->mark_columns_used_by_index().
      
      - New item function register_field_in_read_map(), for marking used columns
        in table->read_map. Used by filesort() to mark all used columns
      
      - Maintain in TABLE->merge_keys set of all keys that are used in query.
        (Simplices some optimization loops)
      
      - Maintain Field->part_of_key_not_clustered which is like Field->part_of_key
        but the field in the clustered key is not assumed to be part of all index.
        (used in opt_range.cc for faster loops)
      
      -  dbug_tmp_use_all_columns(), dbug_tmp_restore_column_map()
         tmp_use_all_columns() and tmp_restore_column_map() functions to temporally
         mark all columns as usable.  The 'dbug_' version is primarily intended
         inside a handler when it wants to just call Field:store() & Field::val()
         functions, but don't need the column maps set for any other usage.
         (ie:: bitmap_is_set() is never called)
      
      - We can't use compare_records() to skip updates for handlers that returns
        a partial column set and the read_set doesn't cover all columns in the
        write set. The reason for this is that if we have a column marked only for
        write we can't in the MySQL level know if the value changed or not.
        The reason this worked before was that MySQL marked all to be written
        columns as also to be read. The new 'optimal' bitmaps exposed this 'hidden
        bug'.
      
      - open_table_from_share() does not anymore setup temporary MEM_ROOT
        object as a thread specific variable for the handler. Instead we
        send the to-be-used MEMROOT to get_new_handler().
        (Simpler, faster code)
      
      
      
      Bugs fixed:
      
      - Column marking was not done correctly in a lot of cases.
        (ALTER TABLE, when using triggers, auto_increment fields etc)
        (Could potentially result in wrong values inserted in table handlers
        relying on that the old column maps or field->set_query_id was correct)
        Especially when it comes to triggers, there may be cases where the
        old code would cause lost/wrong values for NDB and/or InnoDB tables.
      
      - Split thd->options flag OPTION_STATUS_NO_TRANS_UPDATE to two flags:
        OPTION_STATUS_NO_TRANS_UPDATE and OPTION_KEEP_LOG.
        This allowed me to remove some wrong warnings about:
        "Some non-transactional changed tables couldn't be rolled back"
      
      - Fixed handling of INSERT .. SELECT and CREATE ... SELECT that wrongly reset
        (thd->options & OPTION_STATUS_NO_TRANS_UPDATE) which caused us to loose
        some warnings about
        "Some non-transactional changed tables couldn't be rolled back")
      
      - Fixed use of uninitialized memory in ha_ndbcluster.cc::delete_table()
        which could cause delete_table to report random failures.
      
      - Fixed core dumps for some tests when running with --debug
      
      - Added missing FN_LIBCHAR in mysql_rm_tmp_tables()
        (This has probably caused us to not properly remove temporary files after
        crash)
      
      - slow_logs was not properly initialized, which could maybe cause
        extra/lost entries in slow log.
      
      - If we get an duplicate row on insert, change column map to read and
        write all columns while retrying the operation. This is required by
        the definition of REPLACE and also ensures that fields that are only
        part of UPDATE are properly handled.  This fixed a bug in NDB and
        REPLACE where REPLACE wrongly copied some column values from the replaced
        row.
      
      - For table handler that doesn't support NULL in keys, we would give an error
        when creating a primary key with NULL fields, even after the fields has been
        automaticly converted to NOT NULL.
      
      - Creating a primary key on a SPATIAL key, would fail if field was not
        declared as NOT NULL.
      
      
      Cleanups:
      
      - Removed not used condition argument to setup_tables
      
      - Removed not needed item function reset_query_id_processor().
      
      - Field->add_index is removed. Now this is instead maintained in
        (field->flags & FIELD_IN_ADD_INDEX)
      
      - Field->fieldnr is removed (use field->field_index instead)
      
      - New argument to filesort() to indicate that it should return a set of
        row pointers (not used columns). This allowed me to remove some references
        to sql_command in filesort and should also enable us to return column
        results in some cases where we couldn't before.
      
      - Changed column bitmap handling in opt_range.cc to be aligned with TABLE
        bitmap, which allowed me to use bitmap functions instead of looping over
        all fields to create some needed bitmaps. (Faster and smaller code)
      
      - Broke up found too long lines
      
      - Moved some variable declaration at start of function for better code
        readability.
      
      - Removed some not used arguments from functions.
        (setup_fields(), mysql_prepare_insert_check_table())
      
      - setup_fields() now takes an enum instead of an int for marking columns
         usage.
      
      - For internal temporary tables, use handler::write_row(),
        handler::delete_row() and handler::update_row() instead of
        handler::ha_xxxx() for faster execution.
      
      - Changed some constants to enum's and define's.
      
      - Using separate column read and write sets allows for easier checking
        of timestamp field was set by statement.
      
      - Remove calls to free_io_cache() as this is now done automaticly in ha_reset()
      
      - Don't build table->normalized_path as this is now identical to table->path
        (after bar's fixes to convert filenames)
      
      - Fixed some missed DBUG_PRINT(.."%lx") to use "0x%lx" to make it easier to
        do comparision with the 'convert-dbug-for-diff' tool.
      
      
      Things left to do in 5.1:
      
      - We wrongly log failed CREATE TABLE ... SELECT in some cases when using
        row based logging (as shown by testcase binlog_row_mix_innodb_myisam.result)
        Mats has promised to look into this.
      
      - Test that my fix for CREATE TABLE ... SELECT is indeed correct.
        (I added several test cases for this, but in this case it's better that
        someone else also tests this throughly).
        Lars has promosed to do this.
      74cc73d4
  26. 02 Jun, 2006 2 commits
    • igor@rurik.mysql.com's avatar
      Fixed bug #18206. · 37e049db
      igor@rurik.mysql.com authored
      The bug report revealed two problems related to min/max optimization:
      1. If the length of a constant key used in a SARGable condition for
      for the MIN/MAX fields is greater than the length of the field an 
      unwanted warning on key truncation is issued;
      2. If MIN/MAX optimization is applied to a partial index, like INDEX(b(4))
      than can lead to returning a wrong result set.
      37e049db
    • guilhem@mysql.com's avatar
      First push for WL#3146 "less locking in auto_increment". It is a 0-real-change patch. · a4e778f3
      guilhem@mysql.com authored
      New prototype for get_auto_increment() (but new arguments not yet used), to be able
      to reserve a finite interval of auto_increment values from cooperating engines.
      A hint on how many values to reserve is found in handler::estimation_rows_to_insert,
      filled by ha_start_bulk_insert(), new wrapper around start_bulk_insert().
      NOTE: this patch changes nothing, for all engines. But it makes the API ready for those
      engines which will want to do reservation.
      More csets will come to complete WL#3146.
      a4e778f3
  27. 26 May, 2006 1 commit
    • gkodinov@mysql.com's avatar
      BUG#18681: View privileges are broken · a21a2b5b
      gkodinov@mysql.com authored
      The check for view security was lacking several points :
      1. Check with the right set of permissions : for each table ref that
      participates in a view there were the right credentials to use in it's
      security_ctx member, but these weren't used for checking the credentials.
      This makes hard enforcing the SQL SECURITY DEFINER|INVOKER property
      consistently.
      2. Because of the above the security checking for views was just ruled out
      in explicit ways in several places.
      3. The security was checked only for the columns of the tables that are
      brought into the query from a view. So if there is no column reference
      outside of the view definition it was not detecting the lack of access to
      the tables in the view in SQL SECURITY INVOKER mode.
      
      The fix below tries to fix the above 3 points.
      a21a2b5b