Skip to content

Commit

Permalink
Merge pull request #1298 from planetscale/concepts
Browse files Browse the repository at this point in the history 
Docs Review for Concepts
  • Loading branch information
@GuptaManan100
GuptaManan100 authored Dec 22, 2022
2 parents 6eeee80 + b7c3e2f commit 651b9b3
Show file tree
Hide file tree
Showing 6 changed files with 327 additions and 314 deletions.
316 changes: 161 additions & 155 deletions content/en/docs/15.0/concepts/query-rewriting.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -58,13 +58,13 @@ This way, no session state is needed to evaluate the query in MySQL.
### Server System Variables

A user might also want to change one of the many different system variables that MySQL exposes.
Vitess handles system variables in one of four different ways:
Vitess handles system variables in one of five different ways:

* *No op*. For some settings, Vitess will just silently ignore the setting. This is for system variables that don't make much sense in a sharded setting, and don't change the behaviour of MySQL in an interesting way.
* *Check and fail if not already set*. These are settings that should not change, but Vitess will allow SET statements that try to set the variable to whatever it already is.
* *Not supported*. For these settings, attempting to change them will always result in an error.
* *Vitess aware*. These are settings that change Vitess' behaviour, and are not sent down to MySQL
* *Reserved connection*. For some settings, it makes sense to allow them to be set, but it also means that we can't use a shared connection for this user. What this means is that every connection done on this users behalf will need to first have these system variables set, and then keep the connection dedicated. Connection pooling is important for the performance of Vitess, and reserved connections can't be pooled, so this should not be the normal way to run applications on Vitess. Just make sure that the global variable is set to the same value the application will set it to, and Vitess can use connection pooling.
* *Reserved connection*. For some settings, it makes sense to allow them to be set, but it makes using a shared connection for this user much harder. By default, Vitess will first apply these system variables that are set, and then keep the connection dedicated for this user. Connection pooling is important for the performance of Vitess, so this should not be the normal way to run applications on Vitess. Just make sure that the global variable is set to the same value the application will set it to, and Vitess can use connection pooling. Vitess now has support for connection-pooling even for these settings that originally required reserved connections. You can read more about it [here](../../reference/query-serving/reserved-conn/#settings-pool-and-reserved-connections).

In addition to this, Vitess makes sure that @@version includes both the emulated MySQL version and the Vitess version, such as: `5.7.9-vitess-14.0.0`. This value can be changed by using the vtgate flag `--mysql_server_version`.

Expand All @@ -81,159 +81,165 @@ There are a few special functions that Vitess handles without delegating to MySQ

Here is a list of all the system variables that are handled by Vitess and how they are handled.

| *System variable* | *Handled* |
|---|---|
|autocommit|VitessAware|
|client_found_rows|VitessAware|
|skip_query_plan_cache|VitessAware|
|tx_read_only|VitessAware|
|transaction_read_only|VitessAware|
|sql_select_limit|VitessAware|
|transaction_mode|VitessAware|
|workload|VitessAware|
|charset|VitessAware|
|names|VitessAware|
|big_tables| NoOp |
|bulk_insert_buffer_size| NoOp |
|debug| NoOp |
|default_storage_engine| NoOp |
|default_tmp_storage_engine| NoOp |
|innodb_strict_mode| NoOp |
|innodb_support_xa| NoOp |
|innodb_table_locks| NoOp |
|innodb_tmpdir| NoOp |
|join_buffer_size| NoOp |
|keep_files_on_create| NoOp |
|lc_messages| NoOp |
|long_query_time| NoOp |
|low_priority_updates| NoOp |
|max_delayed_threads| NoOp |
|max_insert_delayed_threads| NoOp |
|multi_range_count| NoOp |
|net_buffer_length| NoOp |
|new| NoOp |
|query_cache_type| NoOp |
|query_cache_wlock_invalidate| NoOp |
|query_prealloc_size| NoOp |
|sql_buffer_result| NoOp |
|transaction_alloc_block_size| NoOp |
|wait_timeout| NoOp |
|audit_log_read_buffer_size| NotSupported|
|auto_increment_increment| NotSupported|
|auto_increment_offset| NotSupported|
|binlog_direct_non_transactional_updates| NotSupported|
|binlog_row_image| NotSupported|
|binlog_rows_query_log_events| NotSupported|
|innodb_ft_enable_stopword| NotSupported|
|innodb_ft_user_stopword_table| NotSupported|
|max_points_in_geometry| NotSupported|
|max_sp_recursion_depth| NotSupported|
|myisam_repair_threads| NotSupported|
|myisam_sort_buffer_size| NotSupported|
|myisam_stats_method| NotSupported|
|ndb_allow_copying_alter_table| NotSupported|
|ndb_autoincrement_prefetch_sz| NotSupported|
|ndb_blob_read_batch_bytes| NotSupported|
|ndb_blob_write_batch_bytes| NotSupported|
|ndb_deferred_constraints| NotSupported|
|ndb_force_send| NotSupported|
|ndb_fully_replicated| NotSupported|
|ndb_index_stat_enable| NotSupported|
|ndb_index_stat_option| NotSupported|
|ndb_join_pushdown| NotSupported|
|ndb_log_bin| NotSupported|
|ndb_log_exclusive_reads| NotSupported|
|ndb_row_checksum| NotSupported|
|ndb_use_exact_count| NotSupported|
|ndb_use_transactions| NotSupported|
|ndbinfo_max_bytes| NotSupported|
|ndbinfo_max_rows| NotSupported|
|ndbinfo_show_hidden| NotSupported|
|ndbinfo_table_prefix| NotSupported|
|old_alter_table| NotSupported|
|preload_buffer_size| NotSupported|
|rbr_exec_mode| NotSupported|
|sql_log_off| NotSupported|
|thread_pool_high_priority_connection| NotSupported|
|thread_pool_prio_kickup_timer| NotSupported|
|transaction_write_set_extraction| NotSupported|
|default_week_format|ReservedConn|
|end_markers_in_json|ReservedConn|
|eq_range_index_dive_limit|ReservedConn|
|explicit_defaults_for_timestamp|ReservedConn|
|foreign_key_checks|ReservedConn|
|group_concat_max_len|ReservedConn|
|max_heap_table_size|ReservedConn|
|max_seeks_for_key|ReservedConn|
|max_tmp_tables|ReservedConn|
|min_examined_row_limit|ReservedConn|
|old_passwords|ReservedConn|
|optimizer_prune_level|ReservedConn|
|optimizer_search_depth|ReservedConn|
|optimizer_switch|ReservedConn|
|optimizer_trace|ReservedConn|
|optimizer_trace_features|ReservedConn|
|optimizer_trace_limit|ReservedConn|
|optimizer_trace_max_mem_size|ReservedConn|
|transaction_isolation|ReservedConn|
|tx_isolation|ReservedConn|
|optimizer_trace_offset|ReservedConn|
|parser_max_mem_size|ReservedConn|
|profiling|ReservedConn|
|profiling_history_size|ReservedConn|
|query_alloc_block_size|ReservedConn|
|range_alloc_block_size|ReservedConn|
|range_optimizer_max_mem_size|ReservedConn|
|read_buffer_size|ReservedConn|
|read_rnd_buffer_size|ReservedConn|
|show_create_table_verbosity|ReservedConn|
|show_old_temporals|ReservedConn|
|sort_buffer_size|ReservedConn|
|sql_big_selects|ReservedConn|
|sql_mode|ReservedConn|
|sql_notes|ReservedConn|
|sql_quote_show_create|ReservedConn|
|sql_safe_updates|ReservedConn|
|sql_warnings|ReservedConn|
|tmp_table_size|ReservedConn|
|transaction_prealloc_size|ReservedConn|
|unique_checks|ReservedConn|
|updatable_views_with_limit|ReservedConn|
|binlog_format|CheckAndIgnore|
|block_encryption_mode|CheckAndIgnore|
|character_set_client|CheckAndIgnore|
|character_set_connection|CheckAndIgnore|
|character_set_database|CheckAndIgnore|
|character_set_filesystem|CheckAndIgnore|
|character_set_results|CheckAndIgnore|
|character_set_server|CheckAndIgnore|
|collation_connection|CheckAndIgnore|
|collation_database|CheckAndIgnore|
|collation_server|CheckAndIgnore|
|completion_type|CheckAndIgnore|
|div_precision_increment|CheckAndIgnore|
|innodb_lock_wait_timeout|CheckAndIgnore|
|interactive_timeout|CheckAndIgnore|
|lc_time_names|CheckAndIgnore|
|lock_wait_timeout|CheckAndIgnore|
|max_allowed_packet|CheckAndIgnore|
|max_error_count|CheckAndIgnore|
|max_execution_time|CheckAndIgnore|
|max_join_size|CheckAndIgnore|
|max_length_for_sort_data|CheckAndIgnore|
|max_sort_length|CheckAndIgnore|
|max_user_connections|CheckAndIgnore|
|net_read_timeout|CheckAndIgnore|
|net_retry_count|CheckAndIgnore|
|net_write_timeout|CheckAndIgnore|
|session_track_gtids|CheckAndIgnore|
|session_track_schema", boolean:|CheckAndIgnore|
|session_track_state_change", boolean:|CheckAndIgnore|
|session_track_system_variables|CheckAndIgnore|
|session_track_transaction_info|CheckAndIgnore|
|sql_auto_is_null", boolean:|CheckAndIgnore|
|time_zone|CheckAndIgnore|
|version_tokens_session|CheckAndIgnore|
| *System variable* | *Handled* |
|-----------------------------------------|----------------|
| autocommit | VitessAware |
| client_found_rows | VitessAware |
| skip_query_plan_cache | VitessAware |
| tx_read_only | VitessAware |
| transaction_read_only | VitessAware |
| sql_select_limit | VitessAware |
| transaction_mode | VitessAware |
| ddl_strategy | VitessAware |
| workload | VitessAware |
| charset | VitessAware |
| names | VitessAware |
| session_uuid | VitessAware |
| enable_system_settings | VitessAware |
| read_after_write_gtid | VitessAware |
| read_after_write_timeout | VitessAware |
| session_track_gtids | VitessAware |
| big_tables | NoOp |
| bulk_insert_buffer_size | NoOp |
| debug | NoOp |
| default_storage_engine | NoOp |
| default_tmp_storage_engine | NoOp |
| innodb_strict_mode | NoOp |
| innodb_support_xa | NoOp |
| innodb_table_locks | NoOp |
| innodb_tmpdir | NoOp |
| join_buffer_size | NoOp |
| keep_files_on_create | NoOp |
| lc_messages | NoOp |
| long_query_time | NoOp |
| low_priority_updates | NoOp |
| max_delayed_threads | NoOp |
| max_insert_delayed_threads | NoOp |
| multi_range_count | NoOp |
| net_buffer_length | NoOp |
| new | NoOp |
| query_cache_type | NoOp |
| query_cache_wlock_invalidate | NoOp |
| query_prealloc_size | NoOp |
| sql_buffer_result | NoOp |
| transaction_alloc_block_size | NoOp |
| wait_timeout | NoOp |
| audit_log_read_buffer_size | NotSupported |
| auto_increment_increment | NotSupported |
| auto_increment_offset | NotSupported |
| binlog_direct_non_transactional_updates | NotSupported |
| binlog_row_image | NotSupported |
| binlog_rows_query_log_events | NotSupported |
| innodb_ft_enable_stopword | NotSupported |
| innodb_ft_user_stopword_table | NotSupported |
| max_points_in_geometry | NotSupported |
| max_sp_recursion_depth | NotSupported |
| myisam_repair_threads | NotSupported |
| myisam_sort_buffer_size | NotSupported |
| myisam_stats_method | NotSupported |
| ndb_allow_copying_alter_table | NotSupported |
| ndb_autoincrement_prefetch_sz | NotSupported |
| ndb_blob_read_batch_bytes | NotSupported |
| ndb_blob_write_batch_bytes | NotSupported |
| ndb_deferred_constraints | NotSupported |
| ndb_force_send | NotSupported |
| ndb_fully_replicated | NotSupported |
| ndb_index_stat_enable | NotSupported |
| ndb_index_stat_option | NotSupported |
| ndb_join_pushdown | NotSupported |
| ndb_log_bin | NotSupported |
| ndb_log_exclusive_reads | NotSupported |
| ndb_row_checksum | NotSupported |
| ndb_use_exact_count | NotSupported |
| ndb_use_transactions | NotSupported |
| ndbinfo_max_bytes | NotSupported |
| ndbinfo_max_rows | NotSupported |
| ndbinfo_show_hidden | NotSupported |
| ndbinfo_table_prefix | NotSupported |
| old_alter_table | NotSupported |
| preload_buffer_size | NotSupported |
| rbr_exec_mode | NotSupported |
| sql_log_off | NotSupported |
| thread_pool_high_priority_connection | NotSupported |
| thread_pool_prio_kickup_timer | NotSupported |
| transaction_write_set_extraction | NotSupported |
| default_week_format | ReservedConn |
| end_markers_in_json | ReservedConn |
| eq_range_index_dive_limit | ReservedConn |
| explicit_defaults_for_timestamp | ReservedConn |
| foreign_key_checks | ReservedConn |
| group_concat_max_len | ReservedConn |
| information_schema_stats_expiry | ReservedConn |
| max_heap_table_size | ReservedConn |
| max_seeks_for_key | ReservedConn |
| max_tmp_tables | ReservedConn |
| min_examined_row_limit | ReservedConn |
| old_passwords | ReservedConn |
| optimizer_prune_level | ReservedConn |
| optimizer_search_depth | ReservedConn |
| optimizer_switch | ReservedConn |
| optimizer_trace | ReservedConn |
| optimizer_trace_features | ReservedConn |
| optimizer_trace_limit | ReservedConn |
| optimizer_trace_max_mem_size | ReservedConn |
| transaction_isolation | ReservedConn |
| tx_isolation | ReservedConn |
| optimizer_trace_offset | ReservedConn |
| parser_max_mem_size | ReservedConn |
| profiling | ReservedConn |
| profiling_history_size | ReservedConn |
| query_alloc_block_size | ReservedConn |
| range_alloc_block_size | ReservedConn |
| range_optimizer_max_mem_size | ReservedConn |
| read_buffer_size | ReservedConn |
| read_rnd_buffer_size | ReservedConn |
| show_create_table_verbosity | ReservedConn |
| show_old_temporals | ReservedConn |
| sort_buffer_size | ReservedConn |
| sql_big_selects | ReservedConn |
| sql_mode | ReservedConn |
| sql_notes | ReservedConn |
| sql_quote_show_create | ReservedConn |
| sql_safe_updates | ReservedConn |
| sql_warnings | ReservedConn |
| time_zone | ReservedConn |
| tmp_table_size | ReservedConn |
| transaction_prealloc_size | ReservedConn |
| unique_checks | ReservedConn |
| updatable_views_with_limit | ReservedConn |
| binlog_format | CheckAndIgnore |
| block_encryption_mode | CheckAndIgnore |
| character_set_client | CheckAndIgnore |
| character_set_connection | CheckAndIgnore |
| character_set_database | CheckAndIgnore |
| character_set_filesystem | CheckAndIgnore |
| character_set_results | CheckAndIgnore |
| character_set_server | CheckAndIgnore |
| collation_connection | CheckAndIgnore |
| collation_database | CheckAndIgnore |
| collation_server | CheckAndIgnore |
| completion_type | CheckAndIgnore |
| div_precision_increment | CheckAndIgnore |
| innodb_lock_wait_timeout | CheckAndIgnore |
| interactive_timeout | CheckAndIgnore |
| lc_time_names | CheckAndIgnore |
| lock_wait_timeout | CheckAndIgnore |
| max_allowed_packet | CheckAndIgnore |
| max_error_count | CheckAndIgnore |
| max_execution_time | CheckAndIgnore |
| max_join_size | CheckAndIgnore |
| max_length_for_sort_data | CheckAndIgnore |
| max_sort_length | CheckAndIgnore |
| max_user_connections | CheckAndIgnore |
| net_read_timeout | CheckAndIgnore |
| net_retry_count | CheckAndIgnore |
| net_write_timeout | CheckAndIgnore |
| session_track_schema", boolean: | CheckAndIgnore |
| session_track_state_change", boolean: | CheckAndIgnore |
| session_track_system_variables | CheckAndIgnore |
| session_track_transaction_info | CheckAndIgnore |
| sql_auto_is_null", boolean: | CheckAndIgnore |
| version_tokens_session | CheckAndIgnore |

**Related Vitess Documentation**

Expand Down
2 changes: 1 addition & 1 deletion content/en/docs/15.0/concepts/vtctl.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@
title: vtctl
---

**vtctl** is a command-line tool used to administer a Vitess cluster. It is available as both a standalone tool (`vtctl`) and client-server (`vtctlclient` in combination with `vtctld`). Using client-server is recommended, as it provides an additional layer of security when using the client remotely.
**vtctl** is a command-line tool used to administer a Vitess cluster. It is available as both a standalone tool (`vtctl`) and client-server (`vtctldclient` in combination with `vtctld`). Using client-server is recommended, as it provides an additional layer of security when using the client remotely.

Using vtctl, you can identify primary and replica databases, create tables, initiate failovers, perform resharding operations, and so forth.

Expand Down
2 changes: 1 addition & 1 deletion content/en/docs/15.0/concepts/vtctld.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,4 +4,4 @@ title: vtctld

**vtctld** is an HTTP server that lets you browse the information stored in the Topology Service. It is useful for troubleshooting or for getting a high-level overview of the servers and their current states.

`vtctld` also acts as the server for `vtctlclient` connections.
`vtctld` also acts as the server for `vtctlclient` and `vtctldclient` connections.
Loading

0 comments on commit 651b9b3

Please sign in to comment.