# groonga - An open-source fulltext search engine and column store.

- 日本語

# News

## Release 9.0.3 - 2019-05-29

### Improvements

- [select] Added more query logs.

  - `select` command comes to output a log for below timing.

    - After sorting by drilldown.

    - After filter by drilldown.

  - We can see how much has been finished this command by this feature.

- [logical_select] Added more query logs.

  - `logical_select` command comes to output a log for below timing.

    - After making dynamic columns.

    - After grouping by drilldown.

    - After sorting by drilldown.

    - After filter by drilldown.

    - After sorting by `logical_select`.

  - We can see how much has been finished this command by this feature.

- [logical_select] Improved performance of sort a little when we use `limit` option.

- [index_column_diff] Improved performance.

  - We have greatly shortened the execution speed of this command.

- [index_column_diff] Improved ignore invalid reference.

- [index_column_diff] Added support for duplicated vector element case.

- [Normalizers] Added a new Normalizer `NormalizerNFKC121` based on Unicode NFKC (Normalization Form Compatibility Composition) for Unicode 12.1.

- [TokenFilters] Added a new TokenFilter `TokenFilterNFKC121` based on Unicode NFKC (Normalization Form Compatibility Composition) for Unicode 12.1.

- [grndb] Added a new option `--log-flags`

  - We can specify output items of a log as with groonga executable file.

  - See [groonga executable file] to know about supported log flags.

- [snippet_html] Added a new option for changing a return value when no match by search.

- [plugin_unregister] Added support full path of Windows.

- Added support for multiline log message.

  - The multiline log message is easy to read by this feature.

- Output key in Groonga’s log when we search by index.

- [match_columns parameter] Added a document for indexes with weight.

- [logical_range_filter] Added a explanation for `order` parameter.

- [object_inspect] Added an explanation for new statistics `INDEX_COLUMN_VALUE_STATISTICS_NEXT_PHYSICAL_SEGMENT_ID` and `INDEX_COLUMN_VALUE_STATISTICS_N_PHYSICAL_SEGMENTS`.

- Dropped Ubuntu 14.04 support.

### Fixes

- [index_column_diff] Fixed a bug that too much `remains` are reported.

- Fixed a build error when we use `--without-onigmo` option. [GitHub#951] [Reported by Tomohiro KATO]

- Fixed a vulnerability of “CVE: 2019-11675”. [Reported by Wolfgang Hotwagner]

### Thanks

- Tomohiro KATO

- Wolfgang Hotwagner

## Release 9.0.2 - 2019-04-29

We provide a package for Windows made from VC++ from this release.

We also provide a package for Windows made form MinGW as in the past. However, we will provide it made from VC++ instead of making from MinGW sooner or later.

### Improvements

- [column_create] Added a new flag `INDEX_LARGE` for index column.

  - We can make an index column has space that two times of default by this flag.

  - However, note that it also uses two times of memory usage.

  - This flag useful when index target data are large.

  - Large data must have many records (normally at least 10 millions records) and at least one of the following features.

    - Index targets are multiple columns

    - Index table has tokenizer

- [object_inspect] Added a new statistics `next_physical_segment_id` and `max_n_physical_segments` for physical segment information.

  - We can confirm usage of index column space and max value of index column space by this information.

- [logical_select] Added support for window function over shard.

- [logical_range_filter] Added support for window function over shard.

- [logical_count] Added support for window function over shard.

- We provided a package for Windows made from VC++.

- [io_flush] Added a new option `--recursive dependent`

  - We can all of the specified flush target object, child objects, corresponding table of an index column and corresponding index column are flush target objects.

### Fixes

- Fixed “unknown type name ‘bool’” compilation error in some environments.

- Fixed a bug that incorrect output number over Int32 by command of execute via mruby (e.g. `logical_select`, `logical_range_filter`, `logical_count`, etc.). [GitHub#936] [Patch by HashidaTKS]

### Thanks

- HashidaTKS

## Release 9.0.1 - 2019-03-29

### Improvements

- Added support to acccept null for vector value.

  - You can use select … –columns[vector].flags COLUMN_VECTOR –columns[vector].value “null”

- [dump] Translated document into English.

- Added more checks and logging for invalid indexes. It helps to clarify the index related bugs.

- Improved an explanation about `GRN_TABLE_SELECT_ENOUGH_FILTERED_RATIO` behavior in news at Release 8.0.6 - 2018-08-29.

- [select] Added new argument `--load_table`, `--load_columns` and `--load_values`.

  - You can store a result of `select` in a table that specifying `--load_table`.

  - `--load_values` option specifies columns of result of `select`.

  - `--load_columns` options specifies columns of table that specifying `--load_table`.

  - In this way, you can store values of columns that specifying with `--load_values` into columns that specifying with `--load_columns`.

- [select] Added documentation about `load_table`, `load_columns` and `load_values`.

- [load] Added supoort to display a table of load destination in a query log.

  - A name of table of load destination display as string in `[]` as below.

  - `:000000000000000 load(3): [LoadedLogs][3]`

- Added a new API:

  - `grn_ii_get_flags()`

  - `grn_index_column_diff()`

  - `grn_memory_get_usage()`

- Added `index_column_diff` command to check broken index column. If you want to log progress of command execution, set log level to debug.

### Fixes

- [snippet_html] Changed to return an empty vector for no match.

  - In such a case, an empty vector `[]` is returned instead of `null`.

- Fixed a warning about possibility of counting threads overflow. In real world, it doesn’t affect user because enourmous number of threads is not used. [GitHub#904]

- Fixed build error on macOS [GitHub#909] [Reported by shiro615]

- Fixed a stop word handling bug.

  - This bug occurs when we set the first token as a stop word in our query.

  - If this bug occurs, our search query isn’t hit.

- [Global configurations] Fixed a typo about parameter name of `grn_lock_set_timeout`.

- Fixed a bug that deleted records may be matched because of updating indexes incorrectly.

  - It may occure when large number of records is added or deleted.

- Fixed a memory leak when `logical_range_filter` returns no records. [GitHub#911] [Patch by HashidaTKS]

- Fixed a bug that query will not match because of loading data is not normalized correctly. [PGroonga#GitHub#93, GitHub#912,GitHub#913] [Reported by kamicup and dodaisuke]

  - This bug occurs when load data contains whitespace after KATAKANA and `unify_kana` option is used for normalizer.

- Fixed a bug that an indexes is broken during updating indexes.

  - It may occurs when repeating to add large number of records or delete them for a long term.

- Fixed a crash bug that allocated working area is not enough size when updating indexes.

### Thanks

- shiro615

- HashidaTKS

- kamicup

- dodaisuke

## Release 9.0.0 - 2019-02-09

This is a major version up! But It keeps backward compatibility. You can upgrade to 9.0.0 without rebuilding database.

### Improvements

- [Tokenizers] Added a new tokenizer `TokenPattern`.

  - You can extract tokens by regular expression.

    - This tokenizer extracts only token that matches the regular expression.

  - You can also specify multiple patterns of regular expression.

- [Tokenizers] Added a new tokenizer `TokenTable`.

  - You can extract tokens by a value of columns of existing a table.

- [dump] Added support for dumping binary data.

- [select] Added support for similer search against index column.

  - If you have used multi column index, you can similar search against all source columns by this feature.

- [Normalizers] Added new option `remove_blank` for `NormalizerNFKC100`.

  - This option remove white spaces.

- [groonga executable file] Improve display of thread id in log.

  - Because It was easy to confuse thread id and process id on Windows version, it made clear which is a thread id or a process id.

## Release 8.1.1 - 2019-01-29

### Improvements

- [logical_select] Added new argument `--load_table`, `--load_columns` and `--load_values`.

  - You can store a result of `logical_select` in a table that specifying `--load_table`.

  - `--load_values` option specifies columns of result of `logical_select`.

  - `--load_columns` options specifies columns of table that specifying `--load_table`.

  - In this way, you can store values of columns that specifying with `--load_values` into columns that specifying with `--load_columns`.

- Improve error log when update error of index.

  - Added more information in the log.

    - For example, output source buffer and chunk when occur merge of posting lists error.

    - Also, outputting the log a free space size of a buffer and request size of a buffer when occurs error of allocating a buffer.

- [groonga executable file] Added a new option `--log-flags`.

  - We can specify output items of a log of the Groonga.

  - We can output as below items.

    - Timestamp

    - Log message

    - Location(the location where the log was output)

    - Process id

    - Thread id

  - We can specify prefix as below.

    - `+`

      - This prefix means that “add the flag”.

    - `-`

      - This prefix means that “remove the flag”.

    - No prefix means that “replace existing flags”.

  - Specifically, we can specify flags as below.

    - `none`

      - Output nothing into the log.

    - `time`

      - Output a timestamp into the log.

    - `message`

      - Output log messages into the log.

    - `location`

      - Output the location where the log was output( a file name, a line and a function name) and process id.

    - `process_id`

      - Output a process id into the log.

    - `pid`

      - This flag is an alias of `process_id`.

    - `thread_id`

      - Output thread id into the log.

    - `all`

      - This flag specifies all flags except `none` and `default` flags.

    - `default`

      - Output a timestamp and log messages into the log.

  - We can also specify multiple log flags by separating flags with `|`.

### Fixes

- Fixed a memory leak when occurs index update error.

- [Normalizers] Fixed a bug that stateless normalizers and stateful normalizers return wrong results when we use them at the same time.

  > - Stateless normalizers are below.

  >   - `unify_kana`

  >   - `unify_kana_case`

  >   - `unify_kana_voiced_sound_mark`

  >   - `unify_hyphen`

  >   - `unify_prolonged_sound_mark`

  >   - `unify_hyphen_and_prolonged_sound_mark`

  >   - `unify_middle_dot`

  > - Stateful normalizers are below.

  >   - `unify_katakana_v_sounds`

  >   - `unify_katakana_bu_sound`

  >   - `unify_to_romaji`

## Release 8.1.0 - 2018-12-29

### Improvements

- [httpd] Updated bundled nginx to 1.15.8.

### Fixes

- Fixed a bug that unlock against DB is always executed after flush when after execute a `io_flush` command.

- Fixed a bug that `reindex` command doesn’t finish when execute a `reindex` command against table that has record that has not references.

## Release 8.0.9 - 2018-11-29

### Improvements

- [Tokenizers] Improved that output a tokenizer name in error message when create tokenizer fail.

- [Tokenizers][TokenDelimit] Supported that customizing delimiter of a token.

  - You can use token other than whitespace as a token of delimiter.

- [Tokenizers][TokenDelimit] Added new option `pattern`.

  - You can specify delimiter with regular expression by this option.

- [Tokenizers] Added force_prefix_search value to each token information.

  - “force_prefix” is kept for backward compatibility.

- [Token filters] Added built-in token filter `TokenFilterNFKC100`.

  - You can convert katakana to hiragana like NormalizerNFKC100 with a `unify_kana` option.

- [Token filters][TokenFilterStem] Added new option `algorithm`.

  - You can also stem language other than English(French, Spanish, Portuguese, Italian, Romanian, German, Dutch, Swedish, Norwegian, Danish, Russian, Finnish) by this option.

- [Token filters][TokenFilterStopWord] Added new option `column`.

  - You can specify stop word in a column other than is_stop_word column by this option.

- [dump] Supported output options of token filter options.

  - If you specify a tokenizer like `TokenNgram` or `TokenMecab` etc that has options, you can output these options with `table_list` command.

- [truncate] Supported a table that it has token filter option.

  - You can `truncate` even a tabel that it has token filter like `TokenFilterStem` or `TokenStopWord` that has options.

- [schema] Support output of options of token filter.

- [Normalizers] Added new option for `NormalizerNFKC100` that `unify_to_romaji` option.

  - You can normalize hiragana and katakana to romaji by this option.

- [query-log][show-condition] Supported “func() > 0” case.

- [Windows] Improved that ensure flushing on unmap.

- Improved error message on opening input file error.

- [httpd] Updated bundled nginx to 1.15.7.

  - contains security fix for CVE-2018-16843 and CVE-2018-16844.

### Fixes

- Fixed a memory leak when evaluating window function.

- [groonga-httpd] Fixed bug that log content may be mixed.

- Fixed a bug that generates invalid JSON when occurs error of slice on output_columns.

- Fixed a memory leak when getting nested reference vector column value.

- Fixed a crash bug when outputting warning logs of index corruption.

- Fix a crash bug when temporary vector is reused in expression evaluation.

  - For example, crash when evaluating an expression that uses a vector as below.

  `_score = _score + (vector_size(categories) > 0)`

- Fix a bug that hits a value of vector columns deleted by a delete command.[GitHub PGroonga#85][Reported by dodaisuke]

### Thanks

- dodaisuke

## Release 8.0.8 - 2018-10-29

### Improvements

- [table_list] Supported output options of default tokenizer.

  - If you specify a tokenizer like `TokenNgram` or `TokenMecab` etc that has options, you can output these options with `table_list` command.

- [select] Supported normalizer options in sequential match with `record @ 'query'`.

- [truncate] Supported a table that it has tokenizer option.

  - You can `truncate` even a tabel that it has tokenizer like `TokenNgram` or `TokenMecab` etc that has options.

- [Tokenizers][TokenMecab] Added new option `target_class`

  - This option searches a token of specifying a part-of-speech. For example, you can search only a noun.

  - This option can also specify subclasses and exclude or add specific part-of-speech of specific using `+` or `-`. So, you can also search except a pronoun as below.

    `'TokenMecab("target_class", "-名詞/代名詞", "target_class", "+")'`

- [io_flush] Supported locking of a database during a `io_flush`.

  - Because Groonga had a problem taht is a crash when deleteing a table of a target of a `io_flush` during execution of a `io_flush`.

- [cast_loose] Added a new function `cast_loose`.

  - This function cast to a type to specify. If a value to specify can’t cast, it become to a default value to specify.

- Added optimize the order of evaluation of a conditional expression.(experimental)

  - You can active this feature by setting environment value as below.

    `GRN_EXPR_OPTIMIZE=yes`

- Supported `(?-mix:XXX)` form for index searchable regular expression. [groonga-dev,04683][Reported by Masatoshi SEKI]

  - `(?-mix:XXX)` form treats the same as XXX.

- [httpd] Updated bundled nginx to 1.15.5.

- Supported Ubuntu 18.10 (Cosmic Cuttlefish)

### Fixes

- Fixed a bug that the Groonga GQTP server may fail to accept a new connection. [groonga-dev,04688][Reported by Yutaro Shimamura]

  - It’s caused when interruption client process without using quit.

### Thanks

- Masatoshi SEKI

- Yutaro Shimamura

## Release 8.0.7 - 2018-09-29

### Improvements

- [Tokenizers][TokenMecab] support outputting metadata of Mecab.

  - Added new option `include_class` for `TokenMecab`.

    This option outputs `class` and `subclass` in Mecab’s metadata.

  - Added new option `include_reading` for `TokenMecab`.

    This option outputs `reading` in Mecab’s metadata.

  - Added new option `include_form` for `TokenMecab`.

    This option outputs `inflected_type`, `inflected_form` and `base_form` in Mecab’s metadata.

  - Added new option `use_reading` for `TokenMecab`.

    This option supports a search by kana.

    This option is useful for countermeasure of orthographical variants because it searches with kana.

- [plugin] Groonga now can grab plugins from multiple directories.

  You can specify multiple directories to `GRN_PLUGINS_PATH` separated with “:” on non Windows, “;” on Windows.

  `GRN_PLUGINS_PATH` has high priority than the existing `GRN_PLUGINS_DIR`. Currently, this option is not supported Windows.

- [Tokenizers][TokenNgram] Added new option `unify_alphabet` for `TokenNgram`.

  If we use `unify_alphabet` as `false`, `TokenNgram` uses bigram tokenize method for ASCII character.

- [Tokenizers][TokenNgram] Added new option `unify_symbol` for `TokenNgram`.

  `TokenNgram("unify_symbol", false)` is same behavior of `TokenBigramSplitSymbol`.

- [Tokenizers][TokenNgram] Added new option `unify_digit` for `TokenNgram`.

  If we use `unify_digit` as `false`, If we set false, `TokenNgram` uses bigram tokenize method for digits.

- [httpd] Updated bundled nginx to 1.15.4.

### Fixes

- Fixed wrong score calculations on some cases.

  - It’s caused when adding, multiplication or division numeric to a bool value.

  - It’s caused when comparing a scalar and vector columns using `!=` or `==`.

## Release 8.0.6 - 2018-08-29

### Improvements

- [Tokenizers][TokenMecab] add `chunked_tokenize` and `chunk_size_threshold` options.

- [optimizer] support estimation for query family expressions. It will generate more effective execution plan with query family expressions such as `column @ query`, `column @~ pattern` and so on.

- [optimizer] plug-in -> built-in It’s disabled by default for now. We can enable it by defining `GRN_EXPR_OPTIMIZE=yes` environment variable or using `expression_rewriters` table as before.

- Enable sequential search for enough filtered case by default. If the current result is enough filtered, sequential search is faster than index search. If the current result has only 1% records of all records in a table and less than 1000 records, sequential search is used even when index search is available.

  Cullently, this optimization is applied when search by `==`, `>`, `<`, `>=`, or `<=`.

  When a key of a table that has columns specified by the filter is `ShortText`, you must set `NormalizerAuto` to normalizer of the table to apply this optimization.

  You can disable this feature by `GRN_TABLE_SELECT_ENOUGH_FILTERED_RATIO=0.0` environment variable.

- [load] improve error message. Table name is included.

- [load] add `lock_table` option. If `--lock_table yes` is specified, `load` locks the target table while updating columns and applying `--each`. This option avoids `load` and `delete` conflicts but it’ll reduce load performance.

- [vector_find] avoid to crash with unsupported modes

### Fixes

- [index] fix a bug that offline index construction for text vector with `HASH_KEY`. It creates index with invalid section ID.

- Fix a bug that `--match_columns 'index[0] || index[9]'` uses wrong section.

- [highlighter] fix a wrong highlight bug It’s caused when lexicon is hash table and keyword is less than N of N-gram.

- [mruby] fix a bug that real error is hidden. mruby doesn’t support error propagation by no argument raise. https://github.com/mruby/mruby/issues/290

- [Tokenizers][TokenNgram loose]: fix a not found bug when query has only loose types. `highlight_html()` with lexicon was also broken.

- Fix a bug that text->number cast ignores trailing garbage. “0garbage” should be cast error.

- Fix an optimization bug for `reference_column >= 'key_value'` case

## Release 8.0.5 - 2018-07-29

### Improvements

- [Script syntax] Added complementary explain about similar search against Japanese documents. [GitHub#858][Patch by Yasuhiro Horimoto]

- [time_classify_day_of_week] Added a new API: `time_classify_day_of_week()`.

- Suppressed a warning with `-fstack-protector`. Suggested by OBATA Akio.

- Added a new API: `time_format_iso8601()`.

- Exported a struct `grn_raw_string`.

- Added a new API: `grn_obj_clear_option_values()`. It allows you to clear option values on remove (for persistent) / close (for temporary.)

- [log] Reported index column name for error message `[ii][update][one]`.

- [httpd] Updated bundled nginx to 1.15.2.

- [Ubuntu] Dropped Ubuntu 17.10 (Artful Aardvark) support. It has reached EOL at July 19, 2018.

- [Debian GNU/Linux] Dropped jessie support. Debian’s security and release team will no longer produce updates for jessie.

### Fixes

- Fixed returning wrong result after unfinished `/d/load` data by POST.

- Fixed wrong function call around KyTea.

- [grndb] Added a missing label for the `--force-truncate` option.

- Fixed crash on closing of a database, when a normalizer provided by a plugin (ex. `groonga-normalizer-mysql`) is used with any option.

- Fixed a bug that normalizer/tokenizer options may be ignored. It’s occurred when the same object ID is reused.

## Release 8.0.4 - 2018-06-29

### Improvements

- [log] Add sub error for error message `[ii][update][one]`.

- Added a new API: `grn_highlighter_clear_keywords()`.

- Added a new predicate: `grn_obj_is_number_family_bulk()`.

- Added a new API: `grn_plugin_proc_get_value_mode()`.

- [vector_find] Added a new function `vector_find()`.

- Suppress memcpy warnings in msgpack.

- Updated mruby from 1.0.0 to 1.4.1.

- [doc][grn_obj] Added API reference for `grn_obj_is_index_column()`.

- [windows] Suppress printf format warnings.

- [windows] Suppress warning by msgpack.

- [grn_obj][Plugin] Added encoding converter. rules:

  - grn_ctx::errbuf: grn_encoding

  - grn_logger_put: grn_encoding

  - mruby: UTF-8

  - path: locale

- [mrb] Added `LocaleOutput`.

- [windows] Supported converting image path to grn_encoding.

- [Tokenizers][TokenMecab] Convert error message encoding.

- [window_sum] Supported dynamic column as a target column.

- [doc][grn_obj] Added API reference for `grn_obj_is_vector_column()`.

- [column_create] Added more validations.

  - 1: Full text search index for vector column must have `WITH_SECTION` flag. (Note that TokenDelmit with `WITH_POSITION` without `WITH_SECTION` is permitted. It’s useful pattern for tag search.)

  - 2: Full text search index for vector column must not be multi column index. detail: https://github.com/groonga/groonga/commit/08e2456ba35407e3d5172f71a0200fac2a770142

- [grndb] Disabled log check temporarily. Because it’s not completed yet.

### Fixes

- [sub_filter] Fixed too much score with a too filtered case.

- Fixed build error if KyTea is installed.

- [grndb] Fixed output channel.

- [query-log][show-condition] Maybe fixed a crash bug.

- [highlighter][lexicon] Fixed a not highlighted bug. The keyword wasn’t highlighted if keyword length is less than N (“N”-gram. In many cases, it’s Bigram so “less than 2”).

- [windows] Fixed a base path detection bug. If system locale DLL path includes 0x5c (`\` in ASCII) such as “U+8868 CJK UNIFIED IDEOGRAPH-8868” in CP932, the base path detection is buggy.

- [Tokenizers][TokenNgram] Fixed wrong first character length. It’s caused for “PARENTHESIZED IDEOGRAPH” characters such as “U+3231 PARENTHESIZED IDEOGRAPH STOCK”.

## Release 8.0.3 - 2018-05-29

### Improvements

- [highlight_html] Support highlight of results of the search by `NormalizerNFKC100` or `TokenNgram`.

- [Tokenizers] Added new option for `TokenNgram` that `report_source_location option` . This option used when highlighting with `highlight_html` use a lexicon.

- [Normalizers] Added new option for `NormalizerNFKC100` that `unify_middle_dot option`. This option normalizes middle dot. You can search with or without `・` (middle dot) and regardless of `・` position.

- [Normalizers] Added new option for `NormalizerNFKC100` that `unify_katakana_v_sounds option`. This option normalizes `ヴァヴィヴヴェヴォ` (katakana) to `バビブベボ` (katakana). For example, you can search `バイオリン` (violin) in `ヴァイオリン` (violin).

- [Normalizers] Added new option for `NormalizerNFKC100` that `unify_katakana_bu_sound option`. This option normalizes `ヴァヴィヴゥヴェヴォ` (katakana) to `ブ` (katakana). For example, you can search `セーブル` (katakana) and `セーヴル` in `セーヴェル` (katakana).

- [sub_filter] Supported `sub_filter` optimization for the too filter case. this optimize is valid when records are enough narrowed down before `sub_filter` execution as below.

- [groonga-httpd] Made all workers context address to unique. context address is `#{ID}` of below query log.

  #{TIME_STAMP}|#{MESSAGE}
  #{TIME_STAMP}|#{ID}|>#{QUERY}
  #{TIME_STAMP}|#{ID}|:#{ELAPSED_TIME} #{PROGRESS}
  #{TIME_STAMP}|#{ID}|<#{ELAPSED_TIME} #{RETURN_CODE}

- [delete] Added new options that `limit`. You can limit the number of delete records as below example. `delete --table Users --filter '_key @^ "b"' --limit 4`

- [httpd] Updated bundled nginx to 1.14.0.

### Fixes

- [logical_select] Fixed memory leak when an error occurs in filtered dynamic columns.

- [logical_count] Fixed memory leak on initial dynamic column error.

- [logical_range_filter] Fixed memory leak when an error occurs in dynamic column evaluation.

- [Tokenizers] Fixed a bug that the wrong `source_offset` when a loose tokenizing such as `loose_symbol` option.

- [Normalizers] Fixed a bug that FULLWIDTH LATIN CAPITAL LETTERs such as `U+FF21 FULLWIDTH LATIN CAPITAL LETTER A` aren’t normalized to LATIN SMALL LETTERs such as `U+0061 LATIN SMALL LETTER A`. If you have been used `NormalizerNFKC100` , you must recreate your indexes.

## Release 8.0.2 - 2018-04-29

### Improvements

- [grndb][--force-truncate] Improved `grndb recover --force-truncate` option that it can be truncated even if locks are left on the table.

- [logical_range_filter] Added `sort_keys` option.

- Added a new function `time_format()`. You can specify time format against a column of `Time` type. You can specify with use format of `strftime` .

- [Tokenizers] Support new tokenizer `TokenNgram`. You can change its behavior dynamically via options. Here is a list of available options:

  > - `n` : “N” of Ngram. For example, “3” for trigram.

  > - `loose_symbol` : Tokenize keywords including symbols, to be searched by both queries with/without symbols. For example, a keyword “090-1111-2222” will be found by any of “09011112222”, “090”, “1111”, “2222” and “090-1111-2222”.

  > - `loose_blank` : Tokenize keywords including blanks, to be searched by both queries with/without blanks. For example, a keyword “090 1111 2222” will be found by any of “09011112222”, “090”, “1111”, “2222” and “090 1111 2222”.

  > - `remove_blank` : Tokenize keywords including blanks, to be searched by queries without blanks. For example, a keyword “090 1111 2222” will be found by any of “09011112222”, “090”, “1111” or “2222”. Note that the keyword won’t be found by a query including blanks like “090 1111 2222”.

- [Normalizers] Support new normalizer “NormalizerNFKC100” based on Unicode NFKC (Normalization Form Compatibility Composition) for Unicode 10.0.

- [Normalizers] Support options for “NormalizerNFKC51” and “NormalizerNFKC100” normalizers. You can change their behavior dynamically. Here is a list of available options:

  > - `unify_kana` : Same pronounced characters in all of full-width Hiragana, full-width Katakana and half-width Katakana are regarded as the same character.

  > - `unify_kana_case` : Large and small versions of same letters in all of full-width Hiragana, full-width Katakana and half-width Katakana are regarded as the same character.

  > - `unify_kana_voiced_sound_mark` : Letters with/without voiced sound mark and semi voiced sound mark in all of full-width Hiragana, full-width Katakana and half-width Katakana are regarded as the same character.

  > - `unify_hyphen` : The characters like hyphen are regarded as the hyphen.

  > - `unify_prolonged_sound_mark` : The characters like prolonged sound mark are regarded as the prolonged sound mark.

  > - `unify_hyphen_and_prolonged_sound_mark` : The characters like hyphen and prolonged sound mark are regarded as the hyphen.

- [dump] Support output of tokenizer’s options and normalizer’s options. Groonga 8.0.1 and earlier versions cannot import dump including options for tokenizers or normalizers generated by Groonga 8.0.2 or later, and it will occurs error due to unsupported information.

- [schema] Support output of tokenizer’s options and normalizer’s options. Groonga 8.0.1 and earlier versions cannot import schema including options for tokenizers or normalizers generated by Groonga 8.0.2 or later, and it will occurs error due to unsupported information.

- Supported Ubuntu 18.04 (Bionic Beaver)

### Fixes

- Fixed a bug that unexpected record is matched with space only query. [groonga-dev,04609][Reported by satouyuzh]

- Fixed a bug that wrong scorer may be used. It’s caused when multiple scorers are used as below. `--match_columns 'title || scorer_tf_at_most(content, 2.0)'`.

- Fixed a bug that it may also take so much time to change “thread_limit”.

### Thanks

- satouyuzh

## Release 8.0.1 - 2018-03-29

### Improvements

- [Log] Show `filter` conditions in query log. It’s disabled by default. To enable it, you need to set an environment variable `GRN_QUERY_LOG_SHOW_CONDITION=yes`.

- Install `*.pdb` into the directory where `*.dll` and `*.exe` are installed.

- [logical_count] Support `filtered` stage dynamic columns.

- [logical_count] [post_filter] Added a new filter timing. It’s executed after `filtered` stage columns are generated.

- [logical_select] [post_filter] Added a new filter timing. It’s executed after `filtered` stage columns are generated.

- Support LZ4/Zstd/zlib compression for vector data.

- Support alias to accessor such as `_key`.

- [logical_range_filter] Optimize window function for large result set. If we find enough matched records, we don’t apply window function to the remaining windows.

  TODO: Disable this optimization for small result set if its overhead is not negligible. The overhead is not evaluated yet.

- [select] Added `match_escalation` parameter. You can force to enable match escalation by `--match_escalation yes`. It’s stronger than `--match_escalation_threshold 99999....999` because `--match_escalation yes` also works with `SOME_CONDITIONS && column @ 'query'`. `--match_escalation_threshold` isn’t used in this case.

  The default is `--match_escalation auto`. It doesn’t change the current behavior.

  You can disable match escalation by `--match_escalation no`. It’s the same as `--match_escalation_threshold -1`.

- [httpd] Updated bundled nginx to 1.13.10.

### Fixes

- Fixed memory leak that occurs when a prefix query doesn’t match any token. [GitHub#820][Patch by Naoya Murakami]

- Fixed a bug that a cache for different databases is used when multiple databases are opened in the same process.

- Fixed a bug that a wrong index is constructed. This occurs only when the source of a column is a vector column and `WITH_SECTION` isn’t specified.

- Fixed a bug that a constant value can overflow or underflow in comparison (>,>=,<,<=,==,!=).

### Thanks

- Naoya Murakami

## Release 8.0.0 - 2018-02-09

This is a major version up! But It keeps backward compatibility. You can upgrade to 8.0.0 without rebuilding database.

### Improvements

- [select] Added `--drilldown_adjuster` and `--drilldowns[LABEL].adjuster`. You can adjust score against result of drilldown.

- [Online index construction] Changed environment variable name `GRN_II_REDUCE_EXPIRE_ENABLE` to `GRN_II_REDUCE_EXPIRE_THRESHOLD`.

  `GRN_II_REDUCE_EXPIRE_THRESHOLD=0 == GRN_II_REDUCE_EXPIRE_ENABLE=no`. `GRN_II_REDUCE_EXPIRE_THRESHOLD=-1` uses `ii->chunk->max_map_seg / 2` as threshold. `GRN_II_REDUCE_EXPIRE_THRESHOLD > 0` uses `MIN(ii->chunk->max_map_seg / 2, GRN_II_REDUCE_EXPIRE_THRESHOLD)` as threshold. `GRN_II_REDUCE_EXPIRE_THRESHOLD=32` is the default.

- [between] Accept `between()` without borders. If the number of arguments passed to `between()` is 3, the 2nd and 3rd arguments are handled as the inclusive edges. [GitHub#685]

### Fixes

- Fixed a memory leak for normal hash table. [GitHub:mroonga/mroonga#190][Reported by fuku1]

- Fix a memory leak for normal array.

- [select] Stopped to cache when `output_columns` uses not stable function.

- [Windows] Fixed wrong value report on `WSASend` error.

### Thanks

- fuku1

## Release 7.1.1 - 2018-01-29

### Improvements

- [Ubuntu] Dropped Ubuntu 17.04 (Zesty Zapus) support. It has reached EOL at Jan 13, 2018.

- Added quorum match support. You can use quorum match in both script syntax and query syntax. [groonga-talk,385][Suggested by 付超群]

  TODO: Add documents for quorum match syntax and link to them.

- Added custom similarity threshold support in script syntax. You can use custom similarity threshold in script syntax.

  TODO: Add document for the syntax and link to it.

- [grndb][--force-lock-clear] Added `--force-lock-clear` option. With this option, `grndb` forces to clear locks of database, tables and data columns. You can use your database again even if locks are remained in database, tables and data columns.

  But this option very risky. Normally, you should not use it. If your database is broken, your database is still broken. This option just ignores locks.

- [load] Added surrogate pairs support in escape syntax. For example, `\uD83C\uDF7A` is processed as `🍺`.

- [Windows] Changed to use sparse file on Windows. It reduces disk space and there are no performance demerit.

- [Online index construction] Added `GRN_II_REDUCE_EXPIRE_THRESHOLD` environment variable to control when memory maps are expired in index column. It’s `-1` by default. It means that expire timing is depends on index column size. If index column is smaller, expire timing is more. If index column is larger, expire timing is less.

  You can use the previous behavior by `0`. It means that Groonga always tries to expire.

- [logical_range_filter] [post_filter] Added a new filter timing. It’s executed after `filtered` stage generated columns are generated.

### Fixes

- Reduced resource usage for creating index for reference vector. [GitHub#806][Reported by Naoya Murakami]

- [table_create] Fixed a bug that a table is created even when `token_filters` is invalid. [GitHub#266]

### Thanks

- 付超群

- Naoya Murakami

## Release 7.1.0 - 2017-12-29

### Improvements

- [load] Improved the `load`’s query-log format. Added detail below items in the `load`’s query-log.

  > - outputs number of loaded records.

  > - outputs number of error records and columns.

  > - outputs number of total records.

- [logical_count] Improved the `logical_count`’s query-log format. Added detail below items in the `logical_count`’s query-log.

  > - outputs number of count.

- [logical_select] Improve the `logical_select`’s query-log format. Added detail below items in the `logical_select`’s query-log.

  > - log N outputs.

  > - outputs plain drilldown.

  > - outputs labeled drilldown.

  > - outputs selected in each shard.

  > - use “[…]” for target information.

- [delete] Improved the `delete`’s query-log format. Added detail below items in the `delete`’s query-log.

  > - outputs number of deleted and error records.

  > - outputs number of rest number of records.

- [Groonga HTTP server] The server executed by `groonga -s` ensure stopping by C-c.

- Used `NaN` and `Infinity`, `-Infinity` instead of Lisp representations(`#<nan>` and `#i1/0`, `#-i1/0`).

- Supported vector for drilldown calc target.

- Partially supported keyword extraction from regexp search. It enables `highlight_html` and `snippet_html` for regexp search. [GitHub#787][Reported by takagi01]

- [bulk] Reduced the number of `realloc()`. `grn_bulk_*()` API supports it.

  It improves performance for large output case on Windows. For example, it causes 100x faster for 100MB over output.

  Because `realloc()` is heavy on Windows.

- Enabled `GRN_II_OVERLAP_TOKEN_SKIP_ENABLE` only when its value is “yes”.

- Deprecated `GRN_NGRAM_TOKENIZER_REMOVE_BLANK_DISABLE`. Use `GRN_NGRAM_TOKENIZER_REMOVE_BLANK_ENABLE=no` instead.

- Added new function `index_column_source_records`. It gets source records of index column.[Patch by Naoya Murakami]

- [select] Supported negative “offset” for “offset + size - limit” >= 0

- Added `grn_column_cache`. It’ll improve performance for getter of fixed size column value.

- [groonga executable file] Added `--listen-backlog option`. You can customize `listen(2)`’s backlog by this option.

- [httpd] Updated bundled nginx to 1.13.8.

### Fixes

- Fixed a memory leak in `highlight_full`

- Fixed a crash bug by early unlink It’s not caused by instruction in `grn_expr_parse()` but it’s caused when libgroonga user such as Mroonga uses the following instructions:

  > 1. `grn_expr_append_const("_id")`

  > 2. `grn_expr_append_op(GRN_OP_GET_VALUE)`

### Thanks

- takagi01

- Naoya Murakami

## Release 7.0.9 - 2017-11-29

### Improvements

- Supported newer version of Apache Arrow. In this release, 0.8.0 or later is required for Apache Arrow support.

- [sharding] Added new API for dynamic columns.

  - Groonga::LabeledArguments

- [sharding] Added convenient `Table#select_all` method.

- [logical_range_filter] Supported dynamic columns. Note that `initial` and `filtered` stage are only supported.

- [logical_range_filter] Added documentation about `cache` parameter and dynamic columns.

- [logical_count] Supported dynamic columns. Note that `initial` stage is only supported.

- [logical_count] Added documentation about named parameters.

- [select] Supported `--match_columns _key` without index.

- [in_values] Supported to specify more than 126 values. [GitHub#760] [GitHub#781] [groonga-dev,04449] [Reported by Murata Satoshi]

- [httpd] Updated bundled nginx to 1.13.7.

### Fixes

- [httpd] Fixed build error when old Groonga is already installed. [GitHub#775] [Reported by myamanishi3]

- [in_values] Fixed a bug that `in_values` with too many arguments can cause a crash. This bug is found during supporting more than 126 values. [GitHub#780]

- [cmake] Fixed LZ4 and MessagePack detection. [Reported by Sergei Golubchik]

- [Offline index construction] Fixed a bug that offline index construction for vector column consumes unnecessary resources. If you have a log of elements in one vector column and many records, Groonga will crash. [groonga-dev,04533][Reported by Toshio Uchiyama]

### Thanks

- Murata Satoshi

- myamanishi3

- Sergei Golubchik

- Toshio Uchiyama

## Release 7.0.8 - 2017-10-29

### Improvements

- [windows] Supported backtrace on crash. This feature not only function call history but also source filename and number of lines can be displayed as much as possible. This feature makes problem solving easier.

- Supported `( )` (empty block) only query (`--query "( )"`) for `QUERY_NO_SYNTAX_ERROR`. In the previous version, it caused an error. [GitHub#767]

- Supported `(+)` (only and block) only query (`--query "(+)"`) for `QUERY_NO_SYNTAX_ERROR`. In the previous version, it caused an error. [GitHub#767]

- Supported `~foo` (starting with “~”) query (`--query "~y"`) for `QUERY_NO_SYNTAX_ERROR`. In the previous version, it caused an error. [GitHub#767]

- Modified log level of `expired` from `info` to `debug`. `2017-10-29 14:05:34.123456|i| <0000000012345678:0> expired i=000000000B123456 max=10 (2/2)` This message is logged when memory mapped area for index is unmapped. Thus, this log message is useful information for debugging, in other words, as it is unnecessary information in normal operation, we changed log level from `info` to `debug`.

- Supported Ubuntu 17.10 (Artful Aardvark)

### Fixes

- [dat] Fixed a bug that large file is created unexpectedly in the worst case during database expansion process. This bug may occurs when you create/delete index columns so frequently. In 7.0.7 release, a related bug was fixed - “`table_create` command fails when there are many deleted keys”, but it turns out that it is not enough in the worst case.

- [logical_select] Fixed a bug that when `offset` and `limit` were applied to multiple shards at the same time, there is a case that it returns a fewer number of records unexpectedly.

## Release 7.0.7 - 2017-09-29

### Improvements

- Supported `+` only query (`--query "+"`) for `QUERY_NO_SYNTAX_ERROR`. In the previous version, it caused an error.

- [httpd] Updated bundled nginx to 1.13.5.

- [dump] Added the default argument values to the syntax section.

- [Command version] Supported `--default-command-version 3`.

- Supported caching select result with function call. Now, most of existing functions supports this feature. There are two exception, when `now()` and `rand()` are used in query, select result will not cached. Because of this default behavior change, new APIs are introduced.

  - `grn_proc_set_is_stable()`

  - `grn_proc_is_stable()`

  Note that if you add a new function that may return different result with the same argument, you must call `grn_proc_is_stable(ctx, proc, GRN_FALSE)`. If you don’t call it, select result with the function call is cached and is wrong result for multiple requests.

### Fixes

- [windows] Fixed to clean up file handle correctly on failure when `database_unmap` is executed. There is a case that critical section is not initialized when request is canceled before executing `database_unmap`. In such a case, it caused a crach bug.

- [Tokenizers] Fixed document for wrong tokenizer names. It should be `TokenBigramIgnoreBlankSplitSymbolAlpha` and `TokenBigramIgnoreBlankSplitSymbolAlphaDigit`.

- Changed not to keep created empty file on error.

  In the previous versions, there is a case that empty file keeps remain on error.

  Here is the senario to reproduce:

  > 1. creating new file by grn_fileinfo_open succeeds

  > 2. mapping file by DO_MAP() is failed

  In such a case, it causes an another error such as “already file exists” because of the file which isn’t under control. so these file should be removed during cleanup process.

- Fixed a bug that Groonga may be crashed when search process is executed during executing many updates in a short time.

- [table_create] Fixed a bug that `table_create` failed when there are many deleted keys.

## Release 7.0.6 - 2017-08-29

### Improvements

- Supported prefix match search using multiple indexes. (e.g. `--query "Foo*" --match_columns "TITLE_INDEX_COLUMN||BODY_INDEX_COLUMN"`).

- [window_count] Supported `window_count` function to add count data to result set. It is useful to analyze or filter additionally.

- Added the following API

  - `grn_obj_get_disk_usage():`

  - `GRN_EXPR_QUERY_NO_SYNTAX_ERROR`

  - `grn_expr_syntax_expand_query_by_table()`

  - `grn_table_find_reference_object()`

- [object_inspect] Supported to show disk usage about specified object.

- Supported falling back query parse feature. It is enabled when `QUERY_NO_SYNTAX_ERROR` flag is set to `query_flags`. (this feature is disabled by default). If this flag is set, query never causes syntax error. For example, “A +” is parsed and escaped automatically into “A +”. This behavior is useful when application uses user input directly and doesn’t want to show syntax error to user and in log.

- Supported to adjust score for term in query. “>”, “<”, and “~” operators are supported. For example, “>Groonga” increments score of “Groonga”, “<Groonga” decrements score of “Groonga”. “~Groonga” decreases score of matched document in the current search result. “~” operator doesn’t change search result itself.

- Improved performance to remove table. `thread_limit=1` is not needed for it. The process about checking referenced table existence is done without opening objects. As a result, performance is improved.

- [httpd] Updated bundled nginx to 1.13.4.

### Fixes

- [dump] Fixed a bug that the 7-th unnamed parameter for –sort_hash_table option is ignored.

- [schema] Fixed a typo in command line parameter name. It should be source instead of sources. [groonga-dev,04449] [Reported by murata satoshi]

- [ruby_eval] Fixed crash when ruby_eval returned syntax error. [GitHub#751] [Patch by ryo-pinus]

### Thanks

- murata satoshi

- ryo-pinus

## Release 7.0.5 - 2017-07-29

### Improvements

- [httpd] Updated bundled nginx to 1.13.3. Note that this version contains security fix for CVE-2017-7529.

- [load] Supported to load the value of max UInt64. In the previous versions, max UInt64 value is converted into 0 unexpectedlly.

- Added the following API

  - `grn_window_get_size()` [GitHub#725] [Patch by Naoya Murakami]

- [math_abs] Supported `math_abs()` function to calculate absolute value. [GitHub#721]

- Supported to make `grn_default_logger_set_path()` and `grn_default_query_logger_set_path()` thread safe.

- [windows] Updated bundled pcre library to 8.41.

- [normalize] Improved not to output redundant empty string `""` on error. [GitHub#730]

- [functions/time] Supported to show error message when division by zero was happened. [GitHub#733] [Patch by Naoya Murakami]

- [windows] Changed to map `ERROR_NO_SYSTEM_RESOURCES` to `GRN_RESOURCE_TEMPORARILY_UNAVAILABLE`. In the previous versions, it returns `rc=-1` as a result code. It is not helpful to investigate what actually happened. With this fix, it returns `rc=-12`.

- [functions/min][functions/max] Supported vector column. Now you need not to care scalar column or vector column to use. [GitHub#735] [Patch by Naoya Murakami]

- [dump] Supported `--sort_hash_table` option to sort by `_key` for hash table. Specify `--sort_hash_table yes` to use it.

- [between] Supported to specify index column. [GitHub#740] [Patch by Naoya Murakami]

- [load] Supported Apache Arrow 0.5.0 or later.

- [How to analyze error messages] Added howto article to analyze error message in Groonga.

- [Debian GNU/Linux] Updated required package list to build from source.

- [Ubuntu] Dropped Ubuntu 16.10 (Yakkety Yak) support. It has reached EOL at July 20, 2017.

### Fixes

- Fixed to construct correct fulltext indexes against vector column which type belongs to text family (``ShortText` and so on). This fix resolves that fulltext search doesn’t work well against text vector column after updating indexes. [GitHub#494]

- [thread_limit] Fixed a bug that deadlock occurs when thread_limit?max=1 is requested at once.

- [groonga-httpd] Fixed a mismatch path of pid file between default one and restart command assumed. This mismatch blocked restarting groonga-httpd. [GitHub#743] [Reported by sozaki]

### Thanks

- Naoya Murakami

## Release 7.0.4 - 2017-06-29

### Improvements

- Added physical create/delete operation logs to identify problem for troubleshooting. [GitHub#700,#701]

- [in_records] Improved performance for fixed sized column. It may reduce 50% execution time.

- [grndb] Added `--log-path` option. [GitHub#702,#703]

- [grndb] Added `--log-level` option. [GitHub#706,#708]

- Added the following API

  - `grn_operator_to_exec_func()`

  - `grn_obj_is_corrupt()`

- Improved performance for “FIXED_SIZE_COLUMN OP CONSTANT”. Supported operators are: `==`, `!=`, `<`, `>`, `<=` and `>=`.

- Improved performance for “COLUMN OP VALUE && COLUMN OP VALUE && …”.

- [grndb] Supported corrupted object detection with `grndb check`.

- [io_flush] Supported `--only_opened` option which enables to flush only opened database objects.

- [grndb] Supported to detect/delete orphan “inspect” object. The orphaned “inspect” object is created by renamed command name from `inspect` to `object_inspect`.

### Fixes

- [rpm][centos] Fixed unexpected macro expansion problem with customized build. This bug only affects when rebuilding Groonga SRPM with customized `additional_configure_options` parameter in spec file.

- Fixed missing null check for `grn_table_setoperation()`. There is a possibility of crash bug when indexes are broken. [GitHub#699]

### Thanks

## Release 7.0.3 - 2017-05-29

### Improvements

- [select] Add document about Full text search with specific index name.

- [index] Supported to log warning message which record causes posting list overflows.

- [load][dump] Supported Apache Arrow. [GitHub#691]

- [cmake] Supported linking lz4 in embedded static library build. [Original patch by Sergei Golubchik]

- [delete] Supported to cancel.

- [httpd] Updated bundled nginx to 1.13.0

- Exported the following API

  - grn_plugin_proc_get_caller()

- Added index column related function and selector.

  - Added new selector: index_column_df_ratio_between()

  - Added new function: index_column_df_ratio()

### Fixes

- [delete] Fixed a bug that error isn’t cleared correctly. It affects to following deletions so that it causes unexpected behavior.

- [windows] Fixed a bug that IO version is not detected correctly when the file is opened with `O_CREAT` flag.

- [vector_slice] Fixed a bug that non 4 bytes vector columns can’t slice. [GitHub#695] [Patch by Naoya Murakami]

- Fixed a bug that non 4 bytes fixed vector column can’t sequential match by specifying index of vector. [GitHub#696] [Patch by Naoya Murakami]

- [logical_select] Fixed a bug that “argument out of range” occurs when setting last day of month to the min. [GitHub#698]

### Thanks

- Sergei Golubchik

- Naoya Murakami

## Release 7.0.2 - 2017-04-29

### Improvements

- [logical_select] Supported multiple drilldowns[${LABEL}].columns[${NAME}].window.sort_keys and drilldowns[${LABEL}].columns[${NAME}].window.group_keys.

- [windows] Updated bundled LZ4 to 1.7.5.

- [cache] Supported persistent cache feature.

- [log_level] Update English documentation.

- Added the following APIs:

  - `grn_set_default_cache_base_path()`

  - `grn_get_default_cache_base_path()`

  - `grn_persistent_cache_open()`

  - `grn_cache_default_open()`

- [`groonga --cache-base-path`] Added a new option to use persistent cache.

- [groonga-httpd] [groonga_cache_base_path] Added new configuration to use persistent cache.

- [windows] Updated bundled msgpack to 2.1.1.

- [object_inspect] Supported not only column inspection, but also index column statistics.

- Supported index search for “`.*`” regexp pattern. This feature is enabled by default. Set `GRN_SCAN_INFO_REGEXP_DOT_ASTERISK_ENABLE=no` environment variable to disable this feature.

- [in_records] Added function to use an existing table as condition patterns.

- [Ubuntu] Dropped Ubuntu 12.04 (Precise Pangolin) support because of EOL.

### Fixes

- [logical_select] Fixed a bug that wrong cache is used. This bug was occurred when dynamic column parameter is used.

- [logical_select] Fixed a bug that dynamic columns aren’t created. It’s occurred when no match case.

- [reindex] Fixed a bug that data is lost by reindex. [GitHub#646]

- [httpd] Fixed a bug that response of quit and shutdown is broken JSON when worker is running as another user. [GitHub ranguba/groonga-client#12]

## Release 7.0.1 - 2017-03-29

### Improvements

- Exported the following API

  - grn_ii_cursor_next_pos()

  - grn_table_apply_expr()

  - grn_obj_is_data_column()

  - grn_obj_is_expr()

  - grn_obj_is_scalar_column()

- [dump] Supported to dump weight reference vector.

- [load] Supported to load `array<object>` style weight vector column. The example of `array<object>` style is: `[{"key1": weight1}, {"key2": weight2}]`.

- Supported to search `!(XXX OPERATOR VALUE)` by index. Supported operator is not only `>` but also `>=`, `<`, `<=`, `==` and `!=`.

- Supported index search for “!(column == CONSTANT)”. The example in this case is: `!(column == 29)` and so on.

- Supported more “!” optimization in the following patterns.

  - `!(column @ "X") && (column @ "Y")`

  - `(column @ "Y") && !(column @ "X")`

  - `(column @ "Y") &! !(column @ "X")`

- Supported to search `XXX || !(column @ "xxx")` by index.

- [dump] Changed to use `'{"x": 1, "y": 2}'` style for not referenced weight vector. This change doesn’t affect to old Groonga because it already supports one.

- [experimental] Supported `GRN_ORDER_BY_ESTIMATED_SIZE_ENABLE` environment variable. This variable controls whether query optimization which is based on estimated size is applied or not. This feature is disabled by default. Set `GRN_ORDER_BY_ESTIMATED_SIZE_ENABLE=yes` if you want to try it.

- [select] Added query log for `columns`, `drilldown` evaluation.

- [select] Changed query log format for `drilldown`. This is backward incompatible change, but it only affects users who convert query log by own programs.

- [table_remove] Reduced temporary memory usage. It’s enabled when the number of max threads is 0.

- [select] `columns[LABEL](N)` is used for query log format instead of `columns(N)[LABEL]`..

- [Query expansion] Updated example to use vector column because it is recommended way. [Reported by Gurunavi, Inc]

- Supported to detect canceled request while locking. It fixes the problem that `request_cancel` is ignored unexpectedly while locking.

- [logical_select] Supported `initial` and `filtered` stage dynamic columns. The examples are: `--columns[LABEL].stage initial` or `--columns[LABEL].stage filtered`.

- [logical_select] Supported `match_columns`, `query` and `drilldown_filter` option.

- [highlight_html] Supported similar search.

- [logical_select] Supported `initial` and stage dynamic columns in labeled drilldown. The example is: `--drilldowns[LABEL].stage initial`.

- [logical_select] Supported window function in dynamic column.

- [select] Added documentation about dynamic columns.

- [Window function] Added section about window functions.

- [CentOS] Dropped CentOS 5 support because of EOL.

- [httpd] Updated bundled nginx to 1.11.12

- Supported to disable AND match optimization by environment variable. You can disable this feature by `GRN_TABLE_SELECT_AND_MIN_SKIP_ENABLE=no`. This feature is enable by default.

- [vector_new] Added a new function to create a new vector.

- [select] Added documentation about `drilldown_filter`.

### Fixes

- [lock_clear] Fixed a crash bug against temporary database.

- Fixed a problem that dynamically updated index size was increased for natural language since Grooonga 6.1.4.

- [select] Fixed a bug that “A && B.C @ X” may not return records that should be matched.

- Fixed a conflict with `grn_io_flush()` and `grn_io_expire()`. Without this change, if `io_flush` and `load` command are executed simultaneously in specific timing, it causes a crash bug by access violation.

- [logical_table_remove] Fixed a crash bug when the max number of threads is 1.

### Thanks

- Gurunavi, Inc.

## Release 7.0.0 - 2017-02-09

### Improvements

- [in_values] Supported sequential search for reference vector column. [Patch by Naoya Murakami] [GitHub#629]

- [select] Changed to report error instead of ignoring on invalid `drilldown[LABEL].sort_keys`.

- [select] Removed needless metadata updates on DB. It reduces the case that database lock remains even though `select` command is executed. [Reported by aomi-n]

- [lock_clear] Changed to clear metadata lock by lock_clear against DB.

- [CentOS] Enabled EPEL by default to install Groonga on Amazon Linux.

- [query] Supported “@X” style in script syntax for prefix(“@^”), suffix(“@$”), regexp(“@^”) search.

- [query] Added documentation about available list of mode. The default mode is `MATCH` (“@”) mode which executes full text search.

- [rpm][centos] Supported groonga-token-filter-stem package which provides stemming feature by `TokenFilterStem` token filter on CentOS 7. [GitHub#633] [Reported by Tim Bellefleur]

- [window_record_number] Marked `record_number` as deprecated. Use `window_record_number` instead. `record_number` is still available for backward compatibility.

- [window_sum] Added `window_sum` window function. It’s similar behavior to window function sum() on PostgreSQL.

- Supported to construct offline indexing with in-memory (temporary) `TABLE_DAT_KEY` table. [GitHub#623] [Reported by Naoya Murakami]

- [onigmo] Updated bundled Onigmo to 6.1.1.

- Supported `columns[LABEL].window.group_keys`. It’s used to apply window function for every group.

- [load] Supported to report error on invalid key. It enables you to detect mismatch type of key.

- [load] Supported `--output_errors yes` option. If you specify “yes”, you can get errors for each load failed record. Note that this feature requires command version 3.

- [load] Improve error message on table key cast failure. Instead of “cast failed”, type of table key and target type of table key are also contained in error message.

- [httpd] Updated bundled nginx to 1.11.9.

### Fixes

- Fixed a bug that nonexistent sort keys for `drilldowns[LABEL]` or `slices[LABEL]` causes invalid JSON parse error. [Patch by Naoya Murakami] [GitHub#627]

- Fixed a bug that access to nonexistent sub records for group causes a crash. For example, This bug affects the case when you use `drilldowns[LABEL].sort_keys _sum` without specifying `calc_types`. [Patch by Naoya Murakami] [GitHub#625]

- Fixed a crash bug when tokenizer has an error. It’s caused when tokenizer and token filter are registered and tokenizer has an error.

- [window_record_number] Fixed a bug that arguments for window function is not correctly passed. [GitHub#634][Patch by Naoya Murakami]

### Thanks

- Naoya Murakami

- aomi-n

## The old releases

- News - 6.x
  - Release 6.1.5 - 2017-01-23
  - Release 6.1.4 - 2017-01-18
  - Release 6.1.3 - 2017-01-06
  - Release 6.1.2 - 2016-12-31
  - Release 6.1.1 - 2016-11-29
  - Release 6.1.0 - 2016-10-29
  - Release 6.0.9 - 2016-09-29
  - Release 6.0.8 - 2016-08-29
  - Release 6.0.7 - 2016-07-29
  - Release 6.0.5 - 2016-06-29
  - Release 6.0.4 - 2016-06-06
  - Release 6.0.3 - 2016-05-29
  - Release 6.0.2 - 2016-04-29
  - Release 6.0.1 - 2016-03-29
  - Release 6.0.0 - 2016-02-29
- News - 5.x
  - Release 5.1.2 - 2016-01-29
  - Release 5.1.1 - 2015-12-29
  - Release 5.1.0 - 2015-11-29
  - Release 5.0.9 - 2015-10-29
  - Release 5.0.8 - 2015-09-29
  - Release 5.0.7 - 2015-08-31
  - Release 5.0.6 - 2015-07-29
  - Release 5.0.5 - 2015-06-29
  - Release 5.0.4 - 2015-05-29
  - Release 5.0.3 - 2015-04-29
  - Release 5.0.2 - 2015-03-31
  - Release 5.0.1 - 2015-03-29
  - Release 5.0.0 - 2015-02-09
- News - 4.x
  - Release 4.1.1 - 2015-01-29
  - Release 4.1.0 - 2015-01-09
  - Release 4.0.9 - 2014-12-29
  - Release 4.0.8 - 2014-11-29
  - Release 4.0.7 - 2014-10-29
  - Release 4.0.6 - 2014-09-29
  - Release 4.0.5 - 2014-08-29
  - Release 4.0.4 - 2014-07-29
  - Release 4.0.3 - 2014-06-29
  - Release 4.0.2 - 2014-05-29
  - Release 4.0.1 - 2014-03-29
  - Release 4.0.0 - 2014-02-09
- News - 3.x
  - Release 3.1.2 - 2014-01-29
  - Release 3.1.1 - 2013-12-29
  - Release 3.1.0 - 2013-11-29
  - Release 3.0.9 - 2013-10-29
  - Release 3.0.8 - 2013-09-29
  - Release 3.0.7 - 2013-08-29
  - Release 3.0.6 - 2013-07-29
  - Release 3.0.5 - 2013-06-29
  - Release 3.0.4 - 2013-05-29
  - Release 3.0.3 - 2013-04-29
  - Release 3.0.2 - 2013-03-29
  - Release 3.0.1 - 2013-02-28
  - Release 3.0.0 - 2013-02-09
- News - 2.x
  - Release 2.1.2 - 2013-01-29
  - Release 2.1.1 - 2012-12-29
  - Release 2.1.0 - 2012-12-29
  - Release 2.0.9 - 2012-11-29
  - Release 2.0.8 - 2012-10-29
  - Release 2.0.7 - 2012-09-29
  - Release 2.0.6 - 2012-08-29
  - Release 2.0.5 - 2012-07-29
  - Release 2.0.4 - 2012-06-29
  - Release 2.0.3 - 2012-05-29
  - Release 2.0.2 - 2012-04-29
  - Release 2.0.1 - 2012-03-29
  - Release 2.0.0 - 2012-02-29
- News - 1.3.x
  - Release 1.3.0 - 2012-01-29
- News - 1.2.x
  - Release 1.2.9 - 2011-12-29
  - Release 1.2.8 - 2011-11-29
  - Release 1.2.7 - 2011-10-29
  - Release 1.2.6 - 2011-09-29
  - Release 1.2.5 - 2011-08-29
  - Release 1.2.4 - 2011-07-29
  - Release 1.2.3 - 2011-06-29
  - Release 1.2.2 - 2011-05-29
  - 1.2.1リリース - 2011-04-29
  - 1.2.0リリース - 2011-03-29
- バージョン1.1.xのお知らせ
  - 1.1.0リリース - 2011-02-09
- バージョン1.0.xのお知らせ
  - 1.0.8リリース - 2011-02-02
  - 1.0.7リリース - 2011-01-29
  - 1.0.6リリース - 2010-12-31
  - 1.0.5リリース - 2010-12-29
  - 1.0.4リリース - 2010-11-29
  - 1.0.3リリース - 2010-10-29
  - 1.0.2リリース - 2010-09-09
  - 1.0.1リリース - 2010-09-06
  - 1.0.0リリース - 2010-08-29
- バージョン0.xのお知らせ
  - 0.7.7リリース - 2010-08-25
  - 0.7.6リリース - 2010-08-19
- News in Senna period
  - Senna -> groonga - 2009-01-14
  - 2006-04-05
  - 2006-03-03
  - 2006-01-16
  - 2006-01-12
  - 2005-12-22
  - 2005-10-27
  - 2005-09-17
  - 2005-09-08
  - 2005-08-16
  - 2005-07-05
  - 2005-06-23
  - 2005-04-12