# 内部函数
GaussDB中下列函数使用了内部数据类型，用户无法直接调用，在此章节列出。
#### 选择率计算函数
|   areajoinsel    |     areasel     | arraycontjoinsel |  arraycontsel  |  contjoinsel   |     contsel      |  eqjoinsel   |
|---|---|---|---|---|---|---|
| eqsel            | iclikejoinsel   | iclikesel        | icnlikejoinsel | icnlikesel     | icregexeqjoinsel | icregexeqsel |
| icregexnejoinsel | icregexnesel    | likejoinsel      | likesel        | neqjoinsel     | neqsel           | nlikejoinsel |
| nlikesel         | positionjoinsel | positionsel      | regexeqjoinsel | regexeqsel     | regexnejoinsel   | regexnesel   |
| scalargtjoinsel  | scalargtsel     | scalarltjoinsel  | scalarltsel    | tsmatchjoinsel | tsmatchsel       | -            |
   
#### 统计信息收集函数
| array_typanalyze |          range_typanalyze          | ts_typanalyze |
|---|---|---|
| local_rto_stat   | standby_statement_history_internal | -             |
   
#### 排序内部功能函数
| bpchar_sortsupport | bytea_sortsupport | date_sortsupport | numeric_sortsupport | timestamp_sortsupport |
|---|---|---|---|---|
   
#### 内部类型处理函数
|            abstimerecv            |   euc_jis_2004_to_utf8   |         int2recv         |         line_recv          |      oidvectorrecv_extend      |       tidrecv        |       utf8_to_koi8u        |
|---|---|---|---|---|---|---|
| anyarray_recv                     | euc_jp_to_mic            | int2vectorrecv           | lseg_recv                  | path_recv                      | time_recv            | utf8_to_shift_jis_2004     |
| array_recv                        | euc_jp_to_sjis           | int4recv                 | macaddr_recv               | pg_node_tree_recv              | time_transform       | utf8_to_sjis               |
| ascii_to_mic                      | euc_jp_to_utf8           | int8recv                 | mic_to_ascii               | point_recv                     | timestamp_recv       | utf8_to_uhc                |
| ascii_to_utf8                     | euc_kr_to_mic            | internal_out             | mic_to_big5                | poly_recv                      | timestamp_transform  | utf8_to_win                |
| big5_to_euc_tw                    | euc_kr_to_utf8           | interval_recv            | mic_to_euc_cn              | pound_nexttoken                | timestamptz_recv     | uuid_recv                  |
| big5_to_mic                       | euc_tw_to_big5           | interval_transform       | mic_to_euc_jp              | prsd_nexttoken                 | timetz_recv          | varbit_recv                |
| big5_to_utf8                      | euc_tw_to_mic            | iso_to_koi8r             | mic_to_euc_kr              | range_recv                     | tintervalrecv        | varbit_transform           |
| bit_recv                          | euc_tw_to_utf8           | iso_to_mic               | mic_to_euc_tw              | rawrecv                        | tsqueryrecv          | varchar_transform          |
| boolrecv                          | float4recv               | iso_to_win1251           | mic_to_iso                 | record_recv                    | tsvectorrecv         | varcharrecv                |
| box_recv                          | float8recv               | iso_to_win866            | mic_to_koi8r               | regclassrecv                   | txid_snapshot_recv   | void_recv                  |
| bpcharrecv                        | gb18030_to_utf8          | iso8859_1_to_utf8        | mic_to_latin1              | regconfigrecv                  | uhc_to_utf8          | win_to_utf8                |
| btoidsortsupport                  | gbk_to_utf8              | iso8859_to_utf8          | mic_to_latin2              | regdictionaryrecv              | unknownrecv          | win1250_to_latin2          |
| bytearecv                         | -                        | johab_to_utf8            | mic_to_latin3              | regoperatorrecv                | utf8_to_ascii        | win1250_to_mic             |
| byteawithoutorderwithequalcolrecv | gtsvector_compress       | json_recv                | mic_to_latin4              | regoperrecv                    | utf8_to_big5         | win1251_to_iso             |
| cash_recv                         | gtsvector_consistent     | koi8r_to_iso             | mic_to_sjis                | regprocedurerecv               | utf8_to_euc_cn       | win1251_to_koi8r           |
| charrecv                          | gtsvector_decompress     | koi8r_to_mic             | mic_to_win1250             | regprocrecv                    | utf8_to_euc_jis_2004 | win1251_to_mic             |
| cidr_recv                         | gtsvector_penalty        | koi8r_to_utf8            | mic_to_win1251             | regtyperecv                    | utf8_to_euc_jp       | win1251_to_win866          |
| cidrecv                           | gtsvector_picksplit      | koi8r_to_win1251         | mic_to_win866              | reltimerecv                    | utf8_to_euc_kr       | win866_to_iso              |
| circle_recv                       | gtsvector_same           | koi8r_to_win866          | namerecv                   | shift_jis_2004_to_euc_jis_2004 | utf8_to_euc_tw       | win866_to_koi8r            |
| cstring_recv                      | gtsvector_union          | koi8u_to_utf8            | ngram_nexttoken            | shift_jis_2004_to_utf8         | utf8_to_gb18030      | win866_to_mic              |
| date_recv                         | hll_recv                 | latin1_to_mic            | numeric_recv               | sjis_to_euc_jp                 | utf8_to_gbk          | win866_to_win1251          |
| domain_recv                       | hll_trans_recv           | latin2_to_mic            | numeric_transform          | sjis_to_mic                    | utf8_to_iso8859      | xidrecv                    |
| euc_cn_to_mic                     | -                        | latin2_to_win1250        | nvarchar2recv              | sjis_to_utf8                   | utf8_to_iso8859_1    | xidrecv4                   |
| euc_cn_to_utf8                    | inet_recv                | latin3_to_mic            | oidrecv                    | smalldatetime_recv             | utf8_to_johab        | xml_recv                   |
| euc_jis_2004_to_shift_jis_2004    | int1recv                 | latin4_to_mic            | oidvectorrecv              | textrecv                       | utf8_to_koi8r        | -                          |
| i16toi1                           | int16                    | int16_bool               | int16eq                    | int16div                       | int16ge              | int16gt                    |
| int16in                           | int16le                  | int16lt                  | int16mi                    | int16mul                       | int16ne              | int16out                   |
| int16pl                           | int16recv                | int16send                | numeric_bool               | int2vectorin_extend            | int2vectorout_extend | int2vectorrecv_extend      |
| int2vectorsend_extend             | tdigest_in               | tdigest_merge            | tdigest_merge_to_one       | tdigest_mergep                 | tdigest_out          | -                          |
| anyset_out                        | btint2setcmp             | btint4setcmp             | btint8setcmp               | btsetcmp                       | btsetint2cmp         | btsetint4cmp               |
| btsetint8cmp                      | btsetsortsupport         | float4                   | float8                     | hashsetint                     | hashsettext          | int2                       |
| int2seteq                         | int2setge                | int2setgt                | int2setle                  | int2setlt                      | int2setne            | int4                       |
| int4seteq                         | int4setge                | int4setgt                | int4setle                  | int4setlt                      | int4setne            | int8                       |
| int8seteq                         | int8setge                | int8setgt                | int8setle                  | int8setlt                      | int8setne            | set                        |
| set_in                            | set_out                  | set_recv                 | set_send                   | seteq                          | setge                | setgt                      |
| setint2eq                         | setint2ge                | setint2gt                | setint2le                  | setint2lt                      | setint2ne            | setint4eq                  |
| setint4ge                         | setint4gt                | setint4le                | setint4lt                  | setint4ne                      | setint8eq            | setint8ge                  |
| setint8gt                         | setint8le                | setint8lt                | setint8ne                  | setle                          | setlt                | setne                      |
| settexteq                         | settextge                | settextgt                | settextle                  | settextlt                      | settextne            | settobpchar                |
| settonumber                       | settonvarchar2           | settotext                | settovarchar               | textseteq                      | textsetge            | textsetgt                  |
| textsetle                         | textsetlt                | textsetne                | gb18030_2022_to_utf8       | utf8_to_gb18030_2022           | array_to_nesttable   | array_to_indexby_int_table |
| nesttable_to_array                | indexbytableint_to_array | array_to_nesttable       | array_to_indexby_int_table | zhs16gbk_to_utf8               | utf8_to_zhs16gbk     | zhs16gbk_to_gb18030        |
| gb18030_to_zhs16gbk               | zhs16gbk_to_gb18030_2022 | gb18030_2022_to_zhs16gbk | -                          | -                              | -                    | -                          |
   
#### 聚合操作内部函数
|      array_agg_finalfn       |       array_agg_transfn        |     bytea_string_agg_finalfn     |   bytea_string_agg_transfn   |   date_list_agg_noarg2_transfn    |    date_list_agg_transfn     |   float4_list_agg_noarg2_transfn    |
|---|---|---|---|---|---|---|
| float4_list_agg_transfn      | float8_list_agg_noarg2_transfn | float8_list_agg_transfn          | int2_list_agg_noarg2_transfn | int2_list_agg_transfn             | int4_list_agg_noarg2_transfn | int4_list_agg_transfn               |
| int8_list_agg_noarg2_transfn | int8_list_agg_transfn          | interval_list_agg_noarg2_transfn | interval_list_agg_transfn    | list_agg_finalfn                  | list_agg_noarg2_transfn      | list_agg_transfn                    |
| median_float8_finalfn        | median_interval_finalfn        | median_transfn                   | mode_final                   | numeric_list_agg_noarg2_transfn   | numeric_list_agg_transfn     | ordered_set_transition              |
| percentile_cont_float8_final | percentile_cont_interval_final | string_agg_finalfn               | string_agg_transfn           | timestamp_list_agg_noarg2_transfn | timestamp_list_agg_transfn   | timestamptz_list_agg_noarg2_transfn |
| timestamptz_list_agg_transfn | checksumtext_agg_transfn       | -                                | -                            | -                                 | -                            | -                                   |
   
#### 哈希内部功能函数
| hashbeginscan | hashbuild  | hashbuildempty | hashbulkdelete | hashcostestimate | hashendscan  |   hashgetbitmap   |
|---|---|---|---|---|---|---|
| hashgettuple  | hashinsert | hashmarkpos    | hashmerge      | hashrescan       | hashrestrpos | hashvacuumcleanup |
| hashvarlena   | -          | -              | -              | -                | -            | -                 |
   
#### Btree索引内部功能函数
| cbtreebuild  |  cbtreecanreturn  | cbtreecostestimate |  cbtreegetbitmap  |  cbtreegettuple   |     btbeginscan     |       btbuild       |
|---|---|---|---|---|---|---|
| btbuildempty | btbulkdelete      | btcanreturn        | btcostestimate    | btendscan         | btfloat4sortsupport | btfloat8sortsupport |
| btgetbitmap  | btgettuple        | btinsert           | btint2sortsupport | btint4sortsupport | btint8sortsupport   | btmarkpos           |
| btmerge      | btnamesortsupport | btrescan           | btrestrpos        | bttextsortsupport | btvacuumcleanup     | cbtreeoptions       |
   
#### Psort索引内部函数
| psortbuild | psortcanreturn | psortcostestimate | psortgetbitmap | psortgettuple |
|---|---|---|---|---|
   
#### Ugin索引内部函数
| ugininsert  |      uginbeginscan      |      ugingetbitmap      |      uginrescan      |       uginendscan       |
|---|---|---|---|---|
| uginbuild   | uginbuildempty          | uginbulkdelete          | uginvacuumcleanup    | ugincostestimate        |
| uginoptions | ugin_extract_value_trgm | ugin_extract_query_trgm | ugin_trgm_consistent | ugin_trgm_triconsistent |
   
#### Ubtree索引内部函数
|   ubtbeginscan   |  ubtbuild  | ubtbuildempty | ubtbulkdelete | ubtcanreturn |
|---|---|---|---|---|
| ubtcostestimate  | ubtendscan | ubtgetbitmap  | ubtgettuple   | ubtinsert    |
| ubtmarkpos       | ubtmerge   | ubtoptions    | ubtrescan     | ubtrestrpos  |
| ubtvacuumcleanup | -          | -             | -             | -            |
   
#### GsIVFFLAT索引内部函数
|  ivfflatbeginscan   |  ivfflatbuild  | ivfflatbuildempty | ivfflatbulkdelete |    ivfflatinsert     |
|---|---|---|---|---|
| ivfflatcostestimate | ivfflatendscan | ivfflatoptions    | ivfflatgettuple   | ivfflatvacuumcleanup |
| ivfflatrescan       | -              | -                 | -                 | -                    |
   
#### GsDiskANN索引内部函数
|  diskannbeginscan   |  diskannbuild  | diskannbuildempty | diskannbulkdelete |    diskanninsert     |
|---|---|---|---|---|
| diskanncostestimate | diskannendscan | diskannoptions    | diskanngettuple   | diskannvacuumcleanup |
| diskannrescan       | -              | -                 | -                 | -                    |
   
#### BM25索引内部函数
|  gs_bm25beginscan   |  gs_bm25build  | gs_bm25buildempty | gs_bm25bulkdelete |    gs_bm25insert     |
|---|---|---|---|---|
| gs_bm25costestimate | gs_bm25endscan | gs_bm25options    | gs_bm25gettuple   | gs_bm25vacuumcleanup |
| gs_bm25rescan       | -              | -                 | -                 | -                    |
   
#### plpgsql内部函数
plpgsql_inline_handler
#### 集合相关内部函数
| array_indexby_delete | array_indexby_length | array_integer_deleteidx | array_integer_exists | array_integer_first | array_integer_last |
|---|---|---|---|---|---|
| array_integer_next   | array_integer_prior  | array_varchar_deleteidx | array_varchar_exists | array_varchar_first | array_varchar_last |
| array_varchar_next   | array_varchar_prior  | -                       | -                    | -                   | -                  |
   
#### 外表相关内部函数
|  dist_fdw_handler  |    roach_handler     | streaming_fdw_handler | dist_fdw_validator | file_fdw_handler | file_fdw_validator | log_fdw_handler |
|---|---|---|---|---|---|---|
| dblink_fdw_handler | dblink_fdw_validator | -                     | -                  | -                | -                  | -               |
   
#### 主DN远程读取备DN数据页辅助函数
gs_read_block_from_remote用于读取非段页式表文件的页面。默认只有初始化用户可以查看，其余用户需要赋权后才可以使用。
gs_read_segment_block_from_remote用于读取段页式表文件的页面。默认只有初始化用户可以查看，其余用户需要赋权后才可以使用。
#### 主DN远程读取备DN数据文件辅助函数
gs_read_file_from_remote用于读取指定的文件。gs_repair_file利用gs_read_file_size_from_remote函数获取文件大小后，依赖这个函数将远端文件逐段读取。默认只有初始化用户可以查看，其余用户需要赋权后才可以使用。
gs_read_file_size_from_remote用于读取指定文件的大小。gs_repair_file函数修复文件时，要先获取远端关于这个文件的大小，用于校验本地文件缺失的文件信息，然后将缺失的文件逐个修复。默认只有初始化用户可以查看，其余用户需要赋权后才可以使用。
#### 以备DN实例增量重建其他备或级联备DN实例辅助函数
gs_standby_incremental_filemap_create用于创建备DN增量重建临时filemap文件，用于存储当次增量重建需传输的数据路径与大小。只有初始化用户且application为gs_rewind时可以调用。
gs_standby_incremental_filemap_insert用于向指定临时filemap文件中插入文件信息，指定文件的路径、传输起始点、单次传输数据长度和rebuild标志位。只有初始化用户且application为gs_rewind时可以调用。
gs_standby_incremental_filemap_execute用于获取指定临时filemap文件中存储的文件信息并删除指定filemap，用于备DN增量重建的数据传输。只有初始化用户且application为gs_rewind时可以调用。
#### 账本数据库函数
get_dn_hist_relhash
#### AI特性函数
|     create_snapshot     | create_snapshot_internal | prepare_snapshot_internal | prepare_snapshot | manage_snapshot_internal | archive_snapshot | publish_snapshot |
|---|---|---|---|---|---|---|
| purge_snapshot_internal | purge_snapshot           | sample_snapshot           | -                | -                        | -                | -                |
   
#### PKG_SERVICE函数
| isubmit_on_nodes | submit_on_nodes | - | - | - | - | - |
|---|---|---|---|---|---|---|
   
#### 其他函数
|                                      to_tsvector_for_batch                                      |  value_of_percentile   |   disable_conn    |        bind_variable        |     job_update     |  job_cancel   |         job_finish         |
|---|---|---|---|---|---|---|
| similar_escape                                                                                  | table_skewness （不可用）   | timetz_text       | time_text                   | reltime_text       | abstime_text  | _pg_keysequal              |
| analyze_query (不可用） | analyze_workload （不可用） | assign_table_type | gs_comm_proxy_thread_status | gs_txid_oldestxmin | gs_ltxid      | pg_stat_segment_space_info |
| remote_segment_space_info                                                                       | set_cost_params        | set_weight_params | start_collect_workload      | tdigest_in         | tdigest_merge | tdigest_merge_to_one       |
| tdigest_mergep                                                                                  | tdigest_out            | -                 | -                           | -                  | -             | -                          |
   
#### 视图相关引用函数
adm_hisadm_hist_sqltext_funct_sqlstat_func
adm_hist_sqlstat_idlog_func
adm_hist_sqltext_func
#### gs_txn_snapshot系统表维护函数
gs_insert_delete_txn_snapshot用于GTM-Lite模式下维护全局各节点gs_txn_snapshot系统表，只有系统管理员用户才能调用，当前版本调用该函数将返回f，无实际操作。
#### xmltype类型相关函数
isschemavalid