SHOW PLAN is an SQL statement that displays the execution plan of the previous SELECT statement. The plan is generated and stored during the actual execution, so profiling must be enabled in the current session before running that statement. This can be done with a SET profiling=1 statement.
To view the query execution plan in JSON queries, add "profile": true to the query. The result appears as a profile property in the result set.
Note that there are two things returned in the SQL mode:
transformed_tree, which shows the full-text query decompositionenabled_indexes, which shows information about effective secondary indexes
- SQL
- JSON
📋
set profiling=1;
select * from hn_small where match('dog|cat') limit 0;
show plan;Response
*************************** 1. row ***************************
Variable: transformed_tree
Value: OR(
AND(KEYWORD(dog, querypos=1)),
AND(KEYWORD(cat, querypos=2)))
*************************** 2. row ***************************
Variable: enabled_indexes
Value:
2 rows in set (0.00 sec)In some cases, the evaluated query tree can be quite different from the original one due to expansions and other transformations.
- SQL
- JSON
📋
SET profiling=1;
SELECT id FROM forum WHERE MATCH('@title way* @content hey') LIMIT 1;
SHOW PLAN;Response
Query OK, 0 rows affected (0.00 sec)
+--------+
| id |
+--------+
| 711651 |
+--------+
1 row in set (0.04 sec)
+------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Variable | Value |
+------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| transformed_tree | AND(
OR(
OR(
AND(fields=(title), KEYWORD(wayne, querypos=1, expanded)),
OR(
AND(fields=(title), KEYWORD(ways, querypos=1, expanded)),
AND(fields=(title), KEYWORD(wayyy, querypos=1, expanded)))),
AND(fields=(title), KEYWORD(way, querypos=1, expanded)),
OR(fields=(title), KEYWORD(way*, querypos=1, expanded))),
AND(fields=(content), KEYWORD(hey, querypos=2))) |
+------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)See also EXPLAIN QUERY. It displays the execution tree of a full-text query without actually executing the query.
query property contains the transformed full-text query tree. Each node contains:
type: node type. Can beAND,OR,PHRASE,KEYWORD, etc.description: query subtree for this node shown as a string (inSHOW PLANformat)children: child nodes, if anymax_field_pos: maximum position within a fieldword: transformed keyword. Keyword nodes only.querypos: position of this keyword in a query. Keyword nodes only.excluded: keyword excluded from query. Keyword nodes only.expanded: keyword added by prefix expansion. Keyword nodes only.field_start: keyword must occur at the very start of the field. Keyword nodes only.field_end: keyword must occur at the very end of the field. Keyword nodes only.boost: keyword IDF will be multiplied by this. Keyword nodes only.
SHOW PLAN format=dot allows returning the full-text query execution tree in a hierarchical format suitable for visualization by existing tools, such as https://dreampuf.github.io/GraphvizOnline:
MySQL [(none)]> show plan option format=dot\G
*************************** 1. row ***************************
Variable: transformed_tree
Value: digraph "transformed_tree"
{
0 [shape=record,style=filled,bgcolor="lightgrey" label="AND"]
0 -> 1
1 [shape=record,style=filled,bgcolor="lightgrey" label="AND"]
1 -> 2
2 [shape=record label="i | { querypos=1 }"]
0 -> 3
3 [shape=record,style=filled,bgcolor="lightgrey" label="AND"]
3 -> 4
4 [shape=record label="me | { querypos=2 }"]
}
⪢ Table settings and status
SHOW TABLE STATUS is an SQL statement that displays various per-table statistics.
The syntax is:
SHOW TABLE index_name STATUSDepending on index type, displayed statistic includes different set of rows:
- template:
index_type. - distributed:
index_type,query_time_1min,query_time_5min,query_time_15min,query_time_total,exact_query_time_1min,exact_query_time_5min,exact_query_time_15min,exact_query_time_total,found_rows_1min,found_rows_5min,found_rows_15min,found_rows_total. - percolate:
index_type,stored_queries,ram_bytes,disk_bytes,max_stack_need,average_stack_base,desired_thread_stack,tid,tid_saved,query_time_1min,query_time_5min,query_time_15min,query_time_total,exact_query_time_1min,exact_query_time_5min,exact_query_time_15min,exact_query_time_total,found_rows_1min,found_rows_5min,found_rows_15min,found_rows_total. - disk:
index_type,indexed_documents,indexed_bytes, may be set offield_tokens_*andtotal_tokens,ram_bytes,disk_bytes,disk_mapped,disk_mapped_cached,disk_mapped_doclists,disk_mapped_cached_doclists,disk_mapped_hitlists,disk_mapped_cached_hitlists,killed_documents,killed_rate,query_time_1min,query_time_5min,query_time_15min,query_time_total,exact_query_time_1min,exact_query_time_5min,exact_query_time_15min,exact_query_time_total,found_rows_1min,found_rows_5min,found_rows_15min,found_rows_total. - rt:
index_type,indexed_documents,indexed_bytes, may be set offield_tokens_*andtotal_tokens,ram_bytes,disk_bytes,disk_mapped,disk_mapped_cached,disk_mapped_doclists,disk_mapped_cached_doclists,disk_mapped_hitlists,disk_mapped_cached_hitlists,killed_documents,killed_rate,ram_chunk,ram_chunk_segments_count,disk_chunks,mem_limit,mem_limit_rate,ram_bytes_retired,tid,tid_saved,query_time_1min,query_time_5min,query_time_15min,query_time_total,exact_query_time_1min,exact_query_time_5min,exact_query_time_15min,exact_query_time_total,found_rows_1min,found_rows_5min,found_rows_15min,found_rows_total.
Here is the meaning of these values:
index_type: currently one ofdisk,rt,percolate,template, anddistributed.indexed_documents: number of indexed documents.indexed_bytes: overall size of indexed text. Notice, this value is not strict, since in full-text index that is impossible to strictly recover back stored text to measure it.stored_queries: number of percolate queries, stored in the table.field_tokens_XXX: optional, total per-field lengths (in tokens) across the entire table (used internally forBM25AandBM25Franking functions). Only available for tables built withindex_field_lengths=1.total_tokens: optional, overall sum of allfield_tokens_XXX.ram_bytes: total RAM occupied by table.disk_bytes: total disk space, occupied by table.disk_mapped: total size of file mappings.disk_mapped_cached: total size of file mappings actually cached in RAM.disk_mapped_doclistsanddisk_mapped_cached_doclists: portion of total and cached mappings belonging to document lists.disk_mapped_hitlistsanddisk_mapped_cached_hitlists: portion of total and cached mappings belonging to hit lists. Doclists and hitlists values are shown separately since they're typically large (e.g., about 90% of the whole table's size).killed_documentsandkilled_rate: the first indicates the number of deleted documents and the rate of deleted/indexed. Technically, deleting a document means suppressing it in search output, but it still physically exists in the table and will only be purged after merging/optimizing the table.ram_chunk: size of the RAM chunk of real-time or percolate table.ram_chunk_segments_count: RAM chunk is internally composed of segments, typically no more than 32. This line shows the current count.disk_chunks: number of disk chunks in the real-time table.mem_limit: actual value ofrt_mem_limitfor the table.mem_limit_rate: the rate at which the RAM chunk will be flushed as a disk chunk, e.g., ifrt_mem_limitis 128M and the rate is 50%, a new disk chunk will be saved when the RAM chunk exceeds 64M.ram_bytes_retired: represents the size of garbage in RAM chunks (e.g., deleted or replaced documents not yet permanently removed).max_stack_need: stack space we need to calculate most complex from the stored percolate queries. That is dynamic value, depends on build details as compiler, optimization, hardware, etc.average_stack_base: stack space which is usually occupied on start of calculation of percolate query.desired_thread_stack: sum of above values, rounded up to 128 bytes edge. If this value is greater thanthread_stack, you may not executecall pqover this table, as some stored queries will fail. Defaultthread_stackvalue is 1M (which is 1048576); other values should be configured.tidandtid_saved: represent the state of saving the table.tidincreases with each change (transaction).tid_savedshows the maxtidof the state saved in a RAM chunk in<table>.ramfile. When the numbers differ, some changes exist only in RAM and are also backed by binlog (if enabled). PerformingFLUSH TABLEor scheduling periodic flushing saves these changes. After flushing, the binlog is cleared, andtid_savedrepresents the new actual state.query_time_*,exact_query_time_*: query execution time statistics for the last 1 minute, 5 minutes, 15 minutes, and total since server start; data is encapsulated as a JSON object, including the number of queries and min, max, avg, 95, and 99 percentile values.found_rows_*: statistics of rows found by queries; provided for the last 1 minute, 5 minutes, 15 minutes, and total since server start; data is encapsulated as a JSON object, including the number of queries and min, max, avg, 95, and 99 percentile values.
- SQL
- PHP
- Python
- Javascript
- Java
- C#
📋
mysql> SHOW TABLE statistic STATUS;Response
+-----------------------------+--------------------------------------------------------------------------+
| Variable_name | Value |
+-----------------------------+--------------------------------------------------------------------------+
| index_type | rt |
| indexed_documents | 146000 |
| indexed_bytes | 149504000 |
| ram_bytes | 87674788 |
| disk_bytes | 1762811 |
| disk_mapped | 794147 |
| disk_mapped_cached | 802816 |
| disk_mapped_doclists | 0 |
| disk_mapped_cached_doclists | 0 |
| disk_mapped_hitlists | 0 |
| disk_mapped_cached_hitlists | 0 |
| killed_documents | 0 |
| killed_rate | 0.00% |
| ram_chunk | 86865484 |
| ram_chunk_segments_count | 24 |
| disk_chunks | 1 |
| mem_limit | 134217728 |
| mem_limit_rate | 95.00% |
| ram_bytes_retired | 0 |
| tid | 0 |
| tid_saved | 0 |
| query_time_1min | {"queries":0, "avg":"-", "min":"-", "max":"-", "pct95":"-", "pct99":"-"} |
| query_time_5min | {"queries":0, "avg":"-", "min":"-", "max":"-", "pct95":"-", "pct99":"-"} |
| query_time_15min | {"queries":0, "avg":"-", "min":"-", "max":"-", "pct95":"-", "pct99":"-"} |
| query_time_total | {"queries":0, "avg":"-", "min":"-", "max":"-", "pct95":"-", "pct99":"-"} |
| found_rows_1min | {"queries":0, "avg":"-", "min":"-", "max":"-", "pct95":"-", "pct99":"-"} |
| found_rows_5min | {"queries":0, "avg":"-", "min":"-", "max":"-", "pct95":"-", "pct99":"-"} |
| found_rows_15min | {"queries":0, "avg":"-", "min":"-", "max":"-", "pct95":"-", "pct99":"-"} |
| found_rows_total | {"queries":0, "avg":"-", "min":"-", "max":"-", "pct95":"-", "pct99":"-"} |
+-----------------------------+--------------------------------------------------------------------------+
29 rows in set (0.00 sec)