The function rec_get_offsets_func() used to hit ut_error
due to an invalid rec_get_status() value of a
ROW_FORMAT!=REDUNDANT record. This fix is twofold:
We will not only avoid a crash on corruption in this case,
but we will also make more effort to validate each record
every time we are iterating over index page records.
rec_get_offsets_func(): Do not crash on a corrupted record.
page_rec_get_nth(): Return nullptr on error.
page_dir_slot_get_rec_validate(): Like page_dir_slot_get_rec(),
but validate the pointer and return nullptr on error.
page_cur_search_with_match(), page_cur_search_with_match_bytes(),
page_dir_split_slot(), page_cur_move_to_next():
Indicate failure in a return value.
page_cur_search(): Replaced with page_cur_search_with_match().
rec_get_next_ptr_const(), rec_get_next_ptr(): Replaced with
page_rec_get_next_low().
TODO: rtr_page_split_initialize_nodes(), rtr_update_mbr_field(),
and possibly other SPATIAL INDEX functions fail to properly handle
errors.
Reviewed by: Thirunarayanan Balathandayuthapani
Tested by: Matthias Leich
Performance tested by: Axel Schwenke
This also fixes MDEV-20198: Instant ALTER TABLE is not crash safe
InnoDB dictionary recovery wrongly used the READ UNCOMMITTED isolation
level, causing some mismatch. For example, if a table was renamed or
replaced in a transaction, according to READ UNCOMMITTED the table might
not exist at all.
We implement READ COMMITTED isolation level for accessing the dictionary
tables SYS_TABLES, SYS_COLUMNS, SYS_INDEXES, SYS_FIELDS, SYS_VIRTUAL,
SYS_FOREIGN, SYS_FOREIGN_COLS. For most of these tables, no secondary
index exists. For the secondary indexes (on SYS_TABLES.ID,
SYS_FOREIGN.FOR_NAME, SYS_FOREIGN.REF_NAME), we will always look up
the primary key in the clustered index and check if the record actually
is a committed version.
dict_check_sys_tables(): Recover tablespaces also from delete-marked
committed records, so that if a matching .ibd file exists, it will
be removed by fil_delete_tablespace() when the committed delete-marked
SYS_INDEXES record of the clustered index is purged
in row_purge_remove_clust_if_poss_low().
fil_ibd_open(): Change the Boolean parameter "validate" to a ternary
one, to suppress error messages when the file might not exist.
It is possible that a .ibd file was deleted and the server shut down
before the SYS_INDEXES and SYS_TABLES records were purged. Hence, if
dict_check_sys_tables() finds a committed delete-marked record,
we must not complain if the tablespace file is not found.
On Windows, we msut treat ERROR_PATH_NOT_FOUND (directory not found)
in the same way as ERROR_FILE_NOT_FOUND. This fixes a few failures where
a previous test successfully executed DROP DATABASE (and deleted all
files and the directory), but a committed delete-marked SYS_TABLES
record had not been purged before server restart.
dict_getnext_system_low(): Do not filter out delete-marked records.
dict_startscan_system(), dict_getnext_system(): Do filter out
delete-marked records, for accessing the INFORMATION_SCHEMA tables.
dict_sys_tables_rec_read(): Return the DB_TRX_ID of the committed
version of the record. This is needed in dict_load_table_low().
dict_load_foreign_cols(), dict_load_foreign(): Add a parameter for
the current transaction identifier. In some DDL operations, the
FOREIGN KEY constraints are being loaded from the data dictionary
before the DDL transaction has been committed. For SYS_FOREIGN
and SYS_FOREIGN_COLS, we must implement the special case of
READ COMMITTED that the changes of the uncommitted current transaction
are visible.
dict_load_foreign(): Validate the table name. We could find a
SYS_FOREIGN.ID via a committed delete-marked secondary index record
that does not match the REF_NAME or FOR_NAME of the secondary index record.
dict_load_index_low(): Optionally take the table as a parameter,
so that table->def_trx_id can be updated in case of a
committed delete-marked SYS_INDEXES record corresponding
to DROP INDEX, but not corresponding to an index stub of ADD INDEX.
dict_load_indexes(): Do not update table->def_trx_id
in case of delete-marked records.
rec_is_metadata(), rec_offs_make_valid(), rec_get_offsets_func(),
row_build_low(): Relax some assertions. We may now have
!index->is_instant() even if a metadata record is present in the index.
Previously, the recovery of instant ADD/DROP COLUMN assumed
that READ UNCOMMITTED of the data dictionary will be performed.
Now, we will have a READ COMMITTED copy of the data dictionary
cache, and a READ UNCOMMITTED copy of the metadata record.
btr_page_reorganize_low(): Correctly update the FIL_PAGE_TYPE
when rolling back an instant ADD/DROP COLUMN operation.
row_rec_to_index_entry_impl(): Relax some assertions,
and disallow accessing "extra" fields. This fixes the recovery
of a crash during an instant ADD COLUMN after a successful
instant DROP COLUMN, in the test innodb.instant_alter_crash.
Tested by: Matthias Leich
Between btr_pcur_store_position() and btr_pcur_restore_position()
it is possible that purge empties a table and enlarges
index->n_core_fields and index->n_core_null_bytes.
Therefore, we must cache index->n_core_fields in
btr_pcur_t::old_n_core_fields so that btr_pcur_t::old_rec can be
parsed correctly.
Unfortunately, this is a huge change, because we will replace
"bool leaf" parameters with "ulint n_core"
(passing index->n_core_fields, or 0 for non-leaf pages).
For special cases where we know that index->is_instant() cannot hold,
we may also pass index->n_fields.
Online log for insert operation of redundant table fails with
index->is_instant() assert. Purge can reset the n_core_fields when
alter is waiting to upgrade MDL for commit phase of DDL. In the
meantime, any insert DML tries to log the operation fails with
index is not being instant.
row_log_get_n_core_fields(): Get the n_core_fields of online log
for the given index.
rec_get_converted_size_comp_prefix_low(): Use n_core_fields of online
log when InnoDB calculates the size of data tuple during redundant
row format table rebuild.
rec_convert_dtuple_to_rec_comp(): Use n_core_fields of online log
when InnoDB does the conversion of data tuple to record during
redudant row format table rebuild.
- Adding the test case which has more than 129 instant columns.
The problem was in improper error handling behavior in
`row_upd_build_difference_binary`:
`innobase_free_row_for_vcol` wasn't called.
To eliminate this problem in all potential places, a refactoring has been
made:
* class ib_vcol_row is added. It owns VCOL_STORAGE and heap and maintains
it in RAII manner
* all innobase_allocate_row_for_vcol/innobase_free_row_for_vcol pairs are
substituted
with ib_vcol_row usage
* row_merge_buf_add is only left untouched because it doesn't own vheap
passed as an argument
* innobase_allocate_row_for_vcol does not allocate VCOL_STORAGE anymore and
accepts it as an argument -- this reduces a number of memory allocations
* move rec_printer out of `#ifndef DBUG_OFF` and mark it cold
rec_get_nth_cfield(): Remove a bogus debug assertion.
The function may be invoked by innobase_rec_to_mysql()
for reporting a duplicate key error during CREATE UNIQUE INDEX
or ALTER TABLE...ADD UNIQUE KEY, and in that case the record
will be missing the 5-byte or 6-byte fixed header.
It turns out that in every other code path leading to
rec_get_nth_cfield() we either invoked rec_get_offsets()
ourselves or asserted rec_offs_validate(). So, we can
safely remove the assertion and make debug builds
smaller and faster.
The -Wconversion in GCC seems to be stricter than in clang.
GCC at least since version 4.4.7 issues truncation warnings for
assignments to bitfields, while clang 10 appears to only issue
warnings when the sizes in bytes rounded to the nearest integer
powers of 2 are different.
Before GCC 10.0.0, -Wconversion required more casts and would not
allow some operations, such as x<<=1 or x+=1 on a data type that
is narrower than int.
GCC 5 (but not GCC 4, GCC 6, or any later version) is complaining
about x|=y even when x and y are compatible types that are narrower
than int. Hence, we must rewrite some x|=y as
x=static_cast<byte>(x|y) or similar, or we must disable -Wconversion.
In GCC 6 and later, the warning for assigning wider to bitfields
that are narrower than 8, 16, or 32 bits can be suppressed by
applying a bitwise & with the exact bitmask of the bitfield.
For older GCC, we must disable -Wconversion for GCC 4 or 5 in such
cases.
The bitwise negation operator appears to promote short integers
to a wider type, and hence we must add explicit truncation casts
around them. Microsoft Visual C does not allow a static_cast to
truncate a constant, such as static_cast<byte>(1) truncating int.
Hence, we will use the constructor-style cast byte(~1) for such cases.
This has been tested at least with GCC 4.8.5, 5.4.0, 7.4.0, 9.2.1, 10.0.0,
clang 9.0.1, 10.0.0, and MSVC 14.22.27905 (Microsoft Visual Studio 2019)
on 64-bit and 32-bit targets (IA-32, AMD64, POWER 8, POWER 9, ARMv8).
page_mem_alloc_free(), page_dir_set_n_heap(), page_ptr_set_direction():
Merge with the callers.
page_direction_reset(), page_direction_increment(),
page_zip_dir_insert(), page_zip_write_rec_ext(), page_zip_write_rec():
Add the parameter mtr, and write log.
PageBulk::insert(), PageBulk::finish(): Write log for all changes.
page_cur_rec_insert(), page_cur_insert_rec_write_log(),
page_cur_insert_rec_write_log(): Remove.
page_rec_set_next(), page_header_set_field(), page_header_set_ptr():
Remove. Use lower-level operations with or without logging.
page_zip_dir_add_slot(): Move to the same compilation unit with
its only caller, page_cur_insert_rec_zip().
page_cur_insert_rec_zip(): Mark pieces of code that must be skipped
once this task is completed.
btr_defragment_chunk(): Before starting a mini-transaction that
is writing (a lot), invoke log_free_check(). This should allow
the test innodb.innodb_defrag_concurrent to pass with the
mtr default_mysqld.cnf setting of innodb_log_file_size=10M.
MLOG_BUF_MARGIN: Remove.
No longer write the following redo log records:
MLOG_COMP_LIST_END_DELETE, MLOG_LIST_END_DELETE,
MLOG_COMP_LIST_START_DELETE, MLOG_LIST_START_DELETE,
MLOG_REC_DELETE,MLOG_COMP_REC_DELETE.
Each individual deleted record will be logged separately
using physical log records.
page_dir_slot_set_n_owned(),
page_zip_rec_set_owned(), page_zip_dir_delete(), page_zip_clear_rec():
Add the parameter mtr, and write redo log.
page_dir_slot_set_rec(): Remove. Replaced with lower-level operations
that write redo log when necessary.
page_rec_set_n_owned(): Replaces rec_set_n_owned_old(),
rec_set_n_owned_new().
rec_set_heap_no(): Replaces rec_set_heap_no_old(), rec_set_heap_no_new().
page_mem_free(), page_dir_split_slot(), page_dir_balance_slot():
Add the parameter mtr.
page_dir_set_n_slots(): Merge with the caller page_dir_split_slot().
page_dir_slot_set_rec(): Merge with the callers page_dir_split_slot()
and page_dir_balance_slot().
page_cur_insert_rec_low(), page_cur_insert_rec_zip():
Suppress the logging of lower-level operations.
page_cur_delete_rec_write_log(): Remove.
page_cur_delete_rec(): Do not tolerate mtr=NULL.
rec_convert_dtuple_to_rec_old(), rec_convert_dtuple_to_rec_comp():
Replace rec_set_heap_no_old() and rec_set_heap_no_new() with direct
access that does not involve redo logging.
mtr_t::memcpy(): Do allow non-redo-logged writes to uncompressed pages
of ROW_FORMAT=COMPRESSED pages.
buf_page_io_complete(): Evict the uncompressed page of
a ROW_FORMAT=COMPRESSED page after recovery. Because we no longer
write logical log records for deleting index records, but instead
write physical records that may refer directly to the compressed
page frame of a ROW_FORMAT=COMPRESSED page, and because on recovery
we will only apply the changes to the ROW_FORMAT=COMPRESSED page,
the uncompressed page frame can be stale until page_zip_decompress()
is executed.
recv_parse_or_apply_log_rec_body(): After applying MLOG_ZIP_WRITE_STRING,
ensure that the FIL_PAGE_TYPE of the uncompressed page matches the
compressed page, because buf_flush_init_for_writing() assumes that
field to be valid.
mlog_init_t::mark_ibuf_exist(): Invoke page_zip_decompress(), because
the uncompressed page after buf_page_create() is not necessarily
up to date.
buf_LRU_block_remove_hashed(): Bypass a page_zip_validate() check
during redo log apply.
recv_apply_hashed_log_recs(): Invoke mlog_init.mark_ibuf_exist()
also for the last batch, to ensure that page_zip_decompress() will
be called for freshly initialized pages.
btr_cur_upd_rec_sys(): Replaces row_upd_rec_sys_fields() and
implements redo logging.
row_upd_rec_sys_fields_in_recovery(): Remove, and merge to the
only remaining caller btr_cur_parse_update_in_place().
btr_cur_del_mark_set_clust_rec_log(),
btr_cur_del_mark_set_sec_rec_log(),
btr_cur_set_deleted_flag_for_ibuf():
Remove, and replace with btr_rec_set_deleted<bool>().
page_zip_rec_set_deleted(): Add the parameter mtr, and write a
MLOG_ZIP_WRITE_STRING record to the log.
offset_t: this is a type which represents one record offset.
It's unsigned short int.
a lot of functions: replace ulint with offset_t
btr_pcur_restore_position_func(),
page_validate(),
row_ins_scan_sec_index_for_duplicate(),
row_upd_clust_rec_by_insert_inherit_func(),
row_vers_impl_x_locked_low(),
trx_undo_prev_version_build():
allocate record offsets on the stack instead of waiting for rec_get_offsets()
to allocate it from mem_heap_t. So, reducing memory allocations.
RECORD_OFFSET, INDEX_OFFSET:
now it's less convenient to store pointers in offset_t*
array. One pointer occupies now several offset_t. And those constant are start
indexes into array to places where to store pointer values
REC_OFFS_HEADER_SIZE: adjusted for the new reality
REC_OFFS_NORMAL_SIZE:
increase size from 100 to 300 which means less heap allocations.
And sizeof(offset_t[REC_OFFS_NORMAL_SIZE]) now is 600 bytes which
is smaller than previous 800 bytes.
REC_OFFS_SEC_INDEX_SIZE: adjusted for the new reality
rem0rec.h, rem0rec.ic, rem0rec.cc:
various arguments, return values and local variables types were changed to
fix numerous integer conversions issues.
enum field_type_t:
offset types concept was introduces which replaces old offset flags stuff.
Like in earlier version, 2 upper bits are used to store offset type.
And this enum represents those types.
REC_OFFS_SQL_NULL, REC_OFFS_MASK: removed
get_type(), set_type(), get_value(), combine():
these are convenience functions to work with offsets and it's types
rec_offs_base()[0]:
still uses an old scheme with flags REC_OFFS_COMPACT and REC_OFFS_EXTERNAL
rec_offs_base()[i]:
these have type offset_t now. Two upper bits contains type.
btr_cur_instant_init_low(): Accurately parse the metadata record
header for ROW_FORMAT=DYNAMIC and ROW_FORMAT=COMPACT. CHAR columns
used to be unnecessarily written as nonempty strings of bytes.
mem_heap_dup(): Avoid mem_heap_alloc() and memcpy() of data=NULL, len=0.
trx_undo_report_insert_virtual(), trx_undo_page_report_insert(),
trx_undo_page_report_modify(): Avoid memcpy(ptr, NULL, 0).
dfield_data_is_binary_equal(): Correctly handle data=NULL, len=0.
rec_init_offsets_temp(): Do allow def_val=NULL in the interface.
This clean-up was motivated by WITH_UBSAN, and no bug related to this
was observed in the wild. It should be noted that undefined behaviour
such as memcpy(ptr, NULL, 0) could allow compilers to perform unsafe
optimizations, like it was the case in
commit fc168c3a5e (MDEV-15587).
Use on every virtual function override.
ha_innobase: mark a final
ha_innobase::bas_ext(): remove as unused
ha_innobase::get_cascade_foreign_key_table_list: remove as unused
ha_innobase::end_stmt(): merge into ha_innobase::reset()
Also, related to MDEV-15522, MDEV-17304, MDEV-17835,
remove the Galera xtrabackup tests, because xtrabackup never worked
with MariaDB Server 10.3 due to InnoDB redo log format changes.
Allow ADD COLUMN anywhere in a table, not only adding as the
last column.
Allow instant DROP COLUMN and instant changing the order of columns.
The added columns will always be added last in clustered index records.
In new records, instantly dropped columns will be stored as NULL or
empty when possible.
Information about dropped and reordered columns will be written in
a metadata BLOB (mblob), which is stored before the first 'user' field
in the hidden metadata record at the start of the clustered index.
The presence of mblob is indicated by setting the delete-mark flag in
the metadata record.
The metadata BLOB stores the number of clustered index fields,
followed by an array of column information for each field.
For dropped columns, we store the NOT NULL flag, the fixed length,
and for variable-length columns, whether the maximum length exceeded
255 bytes. For non-dropped columns, we store the column position.
Unlike with MDEV-11369, when a table becomes empty, it cannot
be converted back to the canonical format. The reason for this is
that other threads may hold cached objects such as
row_prebuilt_t::ins_node that could refer to dropped or reordered
index fields.
For instant DROP COLUMN and ROW_FORMAT=COMPACT or ROW_FORMAT=DYNAMIC,
we must store the n_core_null_bytes in the root page, so that the
chain of node pointer records can be followed in order to reach the
leftmost leaf page where the metadata record is located.
If the mblob is present, we will zero-initialize the strings
"infimum" and "supremum" in the root page, and use the last byte of
"supremum" for storing the number of null bytes (which are allocated
but useless on node pointer pages). This is necessary for
btr_cur_instant_init_metadata() to be able to navigate to the mblob.
If the PRIMARY KEY contains any variable-length column and some
nullable columns were instantly dropped, the dict_index_t::n_nullable
in the data dictionary could be smaller than it actually is in the
non-leaf pages. Because of this, the non-leaf pages could use more
bytes for the null flags than the data dictionary expects, and we
could be reading the lengths of the variable-length columns from the
wrong offset, and thus reading the child page number from wrong place.
This is the result of two design mistakes that involve unnecessary
storage of data: First, it is nonsense to store any data fields for
the leftmost node pointer records, because the comparisons would be
resolved by the MIN_REC_FLAG alone. Second, there cannot be any null
fields in the clustered index node pointer fields, but we nevertheless
reserve space for all the null flags.
Limitations (future work):
MDEV-17459 Allow instant ALTER TABLE even if FULLTEXT INDEX exists
MDEV-17468 Avoid table rebuild on operations on generated columns
MDEV-17494 Refuse ALGORITHM=INSTANT when the row size is too large
btr_page_reorganize_low(): Preserve any metadata in the root page.
Call lock_move_reorganize_page() only after restoring the "infimum"
and "supremum" records, to avoid a memcmp() assertion failure.
dict_col_t::DROPPED: Magic value for dict_col_t::ind.
dict_col_t::clear_instant(): Renamed from dict_col_t::remove_instant().
Do not assert that the column was instantly added, because we
sometimes call this unconditionally for all columns.
Convert an instantly added column to a "core column". The old name
remove_instant() could be mistaken to refer to "instant DROP COLUMN".
dict_col_t::is_added(): Rename from dict_col_t::is_instant().
dtype_t::metadata_blob_init(): Initialize the mblob data type.
dtuple_t::is_metadata(), dtuple_t::is_alter_metadata(),
upd_t::is_metadata(), upd_t::is_alter_metadata(): Check if info_bits
refer to a metadata record.
dict_table_t::instant: Metadata about dropped or reordered columns.
dict_table_t::prepare_instant(): Prepare
ha_innobase_inplace_ctx::instant_table for instant ALTER TABLE.
innobase_instant_try() will pass this to dict_table_t::instant_column().
On rollback, dict_table_t::rollback_instant() will be called.
dict_table_t::instant_column(): Renamed from instant_add_column().
Add the parameter col_map so that columns can be reordered.
Copy and adjust v_cols[] as well.
dict_table_t::find(): Find an old column based on a new column number.
dict_table_t::serialise_columns(), dict_table_t::deserialise_columns():
Convert the mblob.
dict_index_t::instant_metadata(): Create the metadata record
for instant ALTER TABLE. Invoke dict_table_t::serialise_columns().
dict_index_t::reconstruct_fields(): Invoked by
dict_table_t::deserialise_columns().
dict_index_t::clear_instant_alter(): Move the fields for the
dropped columns to the end, and sort the surviving index fields
in ascending order of column position.
ha_innobase::check_if_supported_inplace_alter(): Do not allow
adding a FTS_DOC_ID column if a hidden FTS_DOC_ID column exists
due to FULLTEXT INDEX. (This always required ALGORITHM=COPY.)
instant_alter_column_possible(): Add a parameter for InnoDB table,
to check for additional conditions, such as the maximum number of
index fields.
ha_innobase_inplace_ctx::first_alter_pos: The first column whose position
is affected by instant ADD, DROP, or changing the order of columns.
innobase_build_col_map(): Skip added virtual columns.
prepare_inplace_add_virtual(): Correctly compute num_to_add_vcol.
Remove some unnecessary code. Note that the call to
innodb_base_col_setup() should be executed later.
commit_try_norebuild(): If ctx->is_instant(), let the virtual
columns be added or dropped by innobase_instant_try().
innobase_instant_try(): Fill in a zero default value for the
hidden column FTS_DOC_ID (to reduce the work needed in MDEV-17459).
If any columns were dropped or reordered (or added not last),
delete any SYS_COLUMNS records for the following columns, and
insert SYS_COLUMNS records for all subsequent stored columns as well
as for all virtual columns. If any virtual column is dropped, rewrite
all virtual column metadata. Use a shortcut only for adding
virtual columns. This is because innobase_drop_virtual_try()
assumes that the dropped virtual columns still exist in ctx->old_table.
innodb_update_cols(): Renamed from innodb_update_n_cols().
innobase_add_one_virtual(), innobase_insert_sys_virtual(): Change
the return type to bool, and invoke my_error() when detecting an error.
innodb_insert_sys_columns(): Insert a record into SYS_COLUMNS.
Refactored from innobase_add_one_virtual() and innobase_instant_add_col().
innobase_instant_add_col(): Replace the parameter dfield with type.
innobase_instant_drop_cols(): Drop matching columns from SYS_COLUMNS
and all columns from SYS_VIRTUAL.
innobase_add_virtual_try(), innobase_drop_virtual_try(): Let
the caller invoke innodb_update_cols().
innobase_rename_column_try(): Skip dropped columns.
commit_cache_norebuild(): Update table->fts->doc_col.
dict_mem_table_col_rename_low(): Skip dropped columns.
trx_undo_rec_get_partial_row(): Skip dropped columns.
trx_undo_update_rec_get_update(): Handle the metadata BLOB correctly.
trx_undo_page_report_modify(): Avoid out-of-bounds access to record fields.
Log metadata records consistently.
Apparently, the first fields of a clustered index may be updated
in an update_undo vector when the index is ID_IND of SYS_FOREIGN,
as part of renaming the table during ALTER TABLE. Normally, updates of
the PRIMARY KEY should be logged as delete-mark and an insert.
row_undo_mod_parse_undo_rec(), row_purge_parse_undo_rec():
Use trx_undo_metadata.
row_undo_mod_clust_low(): On metadata rollback, roll back the root page too.
row_undo_mod_clust(): Relax an assertion. The delete-mark flag was
repurposed for ALTER TABLE metadata records.
row_rec_to_index_entry_impl(): Add the template parameter mblob
and the optional parameter info_bits for specifying the desired new
info bits. For the metadata tuple, allow conversion between the original
format (ADD COLUMN only) and the generic format (with hidden BLOB).
Add the optional parameter "pad" to determine whether the tuple should
be padded to the index fields (on ALTER TABLE it should), or whether
it should remain at its original size (on rollback).
row_build_index_entry_low(): Clean up the code, removing
redundant variables and conditions. For instantly dropped columns,
generate a dummy value that is NULL, the empty string, or a
fixed length of NUL bytes, depending on the type of the dropped column.
row_upd_clust_rec_by_insert_inherit_func(): On the update of PRIMARY KEY
of a record that contained a dropped column whose value was stored
externally, we will be inserting a dummy NULL or empty string value
to the field of the dropped column. The externally stored column would
eventually be dropped when purge removes the delete-marked record for
the old PRIMARY KEY value.
btr_index_rec_validate(): Recognize the metadata record.
btr_discard_only_page_on_level(): Preserve the generic instant
ALTER TABLE metadata.
btr_set_instant(): Replaces page_set_instant(). This sets a clustered
index root page to the appropriate format, or upgrades from
the MDEV-11369 instant ADD COLUMN to generic ALTER TABLE format.
btr_cur_instant_init_low(): Read and validate the metadata BLOB page
before reconstructing the dictionary information based on it.
btr_cur_instant_init_metadata(): Do not read any lengths from the
metadata record header before reading the BLOB. At this point, we
would not actually know how many nullable fields the metadata record
contains.
btr_cur_instant_root_init(): Initialize n_core_null_bytes in one
of two possible ways.
btr_cur_trim(): Handle the mblob record.
row_metadata_to_tuple(): Convert a metadata record to a data tuple,
based on the new info_bits of the metadata record.
btr_cur_pessimistic_update(): Invoke row_metadata_to_tuple() if needed.
Invoke dtuple_convert_big_rec() for metadata records if the record is
too large, or if the mblob is not yet marked as externally stored.
btr_cur_optimistic_delete_func(), btr_cur_pessimistic_delete():
When the last user record is deleted, do not delete the
generic instant ALTER TABLE metadata record. Only delete
MDEV-11369 instant ADD COLUMN metadata records.
btr_cur_optimistic_insert(): Avoid unnecessary computation of rec_size.
btr_pcur_store_position(): Allow a logically empty page to contain
a metadata record for generic ALTER TABLE.
REC_INFO_DEFAULT_ROW_ADD: Renamed from REC_INFO_DEFAULT_ROW.
This is for the old instant ADD COLUMN (MDEV-11369) only.
REC_INFO_DEFAULT_ROW_ALTER: The more generic metadata record,
with additional information for dropped or reordered columns.
rec_info_bits_valid(): Remove. The only case when this would fail
is when the record is the generic ALTER TABLE metadata record.
rec_is_alter_metadata(): Check if a record is the metadata record
for instant ALTER TABLE (other than ADD COLUMN). NOTE: This function
must not be invoked on node pointer records, because the delete-mark
flag in those records may be set (it is garbage), and then a debug
assertion could fail because index->is_instant() does not necessarily
hold.
rec_is_add_metadata(): Check if a record is MDEV-11369 ADD COLUMN metadata
record (not more generic instant ALTER TABLE).
rec_get_converted_size_comp_prefix_low(): Assume that the metadata
field will be stored externally. In dtuple_convert_big_rec() during
the rec_get_converted_size() call, it would not be there yet.
rec_get_converted_size_comp(): Replace status,fields,n_fields with tuple.
rec_init_offsets_comp_ordinary(), rec_get_converted_size_comp_prefix_low(),
rec_convert_dtuple_to_rec_comp(): Add template<bool mblob = false>.
With mblob=true, process a record with a metadata BLOB.
rec_copy_prefix_to_buf(): Assert that no fields beyond the key and
system columns are being copied. Exclude the metadata BLOB field.
rec_convert_dtuple_to_metadata_comp(): Convert an alter metadata tuple
into a record.
row_upd_index_replace_metadata(): Apply an update vector to an
alter_metadata tuple.
row_log_allocate(): Replace dict_index_t::is_instant()
with a more appropriate condition that ignores dict_table_t::instant.
Only a table on which the MDEV-11369 ADD COLUMN was performed
can "lose its instantness" when it becomes empty. After
instant DROP COLUMN or reordering columns, we cannot simply
convert the table to the canonical format, because the data
dictionary cache and all possibly existing references to it
from other client connection threads would have to be adjusted.
row_quiesce_write_index_fields(): Do not crash when the table contains
an instantly dropped column.
Thanks to Thirunarayanan Balathandayuthapani for discussing the design
and implementing an initial prototype of this.
Thanks to Matthias Leich for testing.
For instant ALTER TABLE, we store a hidden metadata record at the
start of the clustered index, to indicate how the format of the
records differs from the latest table definition.
The term 'default row' is too specific, because it applies to
instant ADD COLUMN only, and we will be supporting more classes
of instant ALTER TABLE later on. For instant ADD COLUMN, we
store the initial default values in the metadata record.
During a table-rebuilding online ALTER TABLE, if
dict_index_t::remove_instant() was invoked on the source table
(because it became empty), we would inadvertently change the way
how log records are written and parsed. We must keep the online_log
format unchanged throughout the whole table-rebuilding operation.
dict_col_t::def_t: Name the type of dict_col_t::def_val.
rec_get_n_add_field_len(), rec_set_n_add_field(): Define globally,
because these will be needed in row_log_table_low().
rec_init_offsets_temp(), rec_init_offsets_comp_ordinary(): Add
the parameter def_val for explicitly passing the default values
of the instantly added columns of the source table, so that
dict_index_t::instant_field_value() will not be called during
row_log_table_apply(). This allows us to consistently parse the
online_log records, even if the source table was converted
to the canonical non-instant format during the rebuild operation.
row_log_t::non_core_fields[]: The default values of the
instantly added columns on the source table; copied
during ha_innobase::prepare_inplace_alter_table()
while the table is exclusively locked.
row_log_t::instant_field_value(): Accessor to non_core_fields[],
analogous to dict_index_t::instant_field_value().
row_log_table_low(): Add fake_extra_size bytes to the record
header if the source table was converted to the canonical format
during the operation.
row_log_allocate(): Initialize row_log_t::non_core_fields.
During an online table rebuild, a table could be emptied and converted
from 'instant ADD' format to plain (pre-10.3) format. All online_log
records for rebuilding the table must be written and parsed in the
format of the table that existed at the start of the operation.
row_log_t::n_core_fields: A new field for recording index->n_core_fields
when online ALTER is initiated in row_log_allocate().
row_log_t::is_instant(): Determine if the log is in the instant format.
Only invoked by the row_log_table_ family of functions.
dict_index_t::get_n_nullable(): Remove is_instant() debug assertions.
Because a table can be converted to non-instant format during a
table-rebuilding ALTER TABLE, these assertions would be bogus when
executing row_log_table_apply().
rec_init_offsets_temp(): Add the parameter n_core for passing the
original index->n_core_fields.
rec_init_offsets_temp(): Add a 3-parameter variant.
rec_init_offsets_comp_ordinary(): Add the parameter n_core for
passing the index->n_core_fields.
