Faceted search is as crucial to a modern search application as autocomplete, spell correction, and search keywords highlighting, especially in e-commerce products.
Faceted search comes in handy when dealing with large quantities of data and various interconnected properties, such as size, color, manufacturer, or other factors. When querying vast amounts of data, search results frequently include numerous entries that don't match the user's expectations. Faceted search enables the end user to explicitly define the criteria they want their search results to satisfy.
In Manticore Search, there's an optimization that maintains the result set of the original query and reuses it for each facet calculation. Since the aggregations are applied to an already calculated subset of documents, they're fast, and the total execution time can often be only slightly longer than the initial query. Facets can be added to any query, and the facet can be any attribute or expression. A facet result includes the facet values and the facet counts. Facets can be accessed using the SQL SELECT statement by declaring them at the very end of the query.
The facet values can originate from an attribute, a JSON property within a JSON attribute, or an expression. Facet values can also be aliased, but the alias must be unique across all result sets (main query result set and other facets result sets). The facet value is derived from the aggregated attribute/expression, but it can also come from another attribute/expression.
FACET {expr_list} [BY {expr_list} ] [DISTINCT {field_name}] [ORDER BY {expr | FACET()} {ASC | DESC}] [LIMIT [offset,] count]Multiple facet declarations must be separated by a whitespace.
Facets can be defined in the aggs node:
"aggs" :
{
"group name" :
{
"terms" :
{
"field":"attribute name",
"size": 1000
}
"sort": [ {"attribute name": { "order":"asc" }} ]
}
}where:
group nameis an alias assigned to the aggregationfieldvalue must contain the name of the attribute or expression being faceted- optional
sizespecifies the maximum number of buckets to include in the result. When not specified, it inherits the main query's limit. More details can be found in the Size of facet result section. - optional
sortspecifies an array of attributes and/or additional properties using the same syntax as the "sort" parameter in the main query.
The result set will contain an aggregations node with the returned facets, where key is the aggregated value and doc_count is the aggregation count.
"aggregations": {
"group name": {
"buckets": [
{
"key": 10,
"doc_count": 1019
},
{
"key": 9,
"doc_count": 954
},
{
"key": 8,
"doc_count": 1021
},
{
"key": 7,
"doc_count": 1011
},
{
"key": 6,
"doc_count": 997
}
]
}
} - SQL
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SELECT *, price AS aprice FROM facetdemo LIMIT 10 FACET price LIMIT 10 FACET brand_id LIMIT 5;+------+-------+----------+---------------------+------------+-------------+---------------------------------------+------------+--------+
| id | price | brand_id | title | brand_name | property | j | categories | aprice |
+------+-------+----------+---------------------+------------+-------------+---------------------------------------+------------+--------+
| 1 | 306 | 1 | Product Ten Three | Brand One | Six_Ten | {"prop1":66,"prop2":91,"prop3":"One"} | 10,11 | 306 |
| 2 | 400 | 10 | Product Three One | Brand Ten | Four_Three | {"prop1":69,"prop2":19,"prop3":"One"} | 13,14 | 400 |
...
| 9 | 560 | 6 | Product Two Five | Brand Six | Eight_Two | {"prop1":90,"prop2":84,"prop3":"One"} | 13,14 | 560 |
| 10 | 229 | 9 | Product Three Eight | Brand Nine | Seven_Three | {"prop1":84,"prop2":39,"prop3":"One"} | 12,13 | 229 |
+------+-------+----------+---------------------+------------+-------------+---------------------------------------+------------+--------+
10 rows in set (0.00 sec)
+-------+----------+
| price | count(*) |
+-------+----------+
| 306 | 7 |
| 400 | 13 |
...
| 229 | 9 |
| 595 | 10 |
+-------+----------+
10 rows in set (0.00 sec)
+----------+----------+
| brand_id | count(*) |
+----------+----------+
| 1 | 1013 |
| 10 | 998 |
| 5 | 1007 |
| 8 | 1033 |
| 7 | 965 |
+----------+----------+
5 rows in set (0.00 sec)Data can be faceted by aggregating another attribute or expression. For example if the documents contain both the brand id and name, we can return in facet the brand names, but aggregate the brand ids. This can be done by using FACET {expr1} BY {expr2}
- SQL
SELECT * FROM facetdemo FACET brand_name by brand_id;+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+
| id | price | brand_id | title | brand_name | property | j | categories |
+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+
| 1 | 306 | 1 | Product Ten Three | Brand One | Six_Ten | {"prop1":66,"prop2":91,"prop3":"One"} | 10,11 |
| 2 | 400 | 10 | Product Three One | Brand Ten | Four_Three | {"prop1":69,"prop2":19,"prop3":"One"} | 13,14 |
....
| 19 | 855 | 1 | Product Seven Two | Brand One | Eight_Seven | {"prop1":63,"prop2":78,"prop3":"One"} | 10,11,12 |
| 20 | 31 | 9 | Product Four One | Brand Nine | Ten_Four | {"prop1":79,"prop2":42,"prop3":"One"} | 12,13,14 |
+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+
20 rows in set (0.00 sec)
+-------------+----------+
| brand_name | count(*) |
+-------------+----------+
| Brand One | 1013 |
| Brand Ten | 998 |
| Brand Five | 1007 |
| Brand Nine | 944 |
| Brand Two | 990 |
| Brand Six | 1039 |
| Brand Three | 1016 |
| Brand Four | 994 |
| Brand Eight | 1033 |
| Brand Seven | 965 |
+-------------+----------+
10 rows in set (0.00 sec)If you need to remove duplicates from the buckets returned by FACET, you can use DISTINCT field_name, where field_name is the field by which you want to perform deduplication. It can also be id (which is the default) if you make a FACET query against a distributed table and are not sure whether you have unique ids in the tables (the tables should be local and have the same schema).
If you have multiple FACET declarations in your query, field_name should be the same in all of them.
DISTINCT returns an additional column count(distinct ...) before the column count(*), allowing you to obtain both results without needing to make another query.
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SELECT brand_name, property FROM facetdemo FACET brand_name distinct property;+-------------+----------+
| brand_name | property |
+-------------+----------+
| Brand Nine | Four |
| Brand Ten | Four |
| Brand One | Five |
| Brand Seven | Nine |
| Brand Seven | Seven |
| Brand Three | Seven |
| Brand Nine | Five |
| Brand Three | Eight |
| Brand Two | Eight |
| Brand Six | Eight |
| Brand Ten | Four |
| Brand Ten | Two |
| Brand Four | Ten |
| Brand One | Nine |
| Brand Four | Eight |
| Brand Nine | Seven |
| Brand Four | Five |
| Brand Three | Four |
| Brand Four | Two |
| Brand Four | Eight |
+-------------+----------+
20 rows in set (0.00 sec)
+-------------+--------------------------+----------+
| brand_name | count(distinct property) | count(*) |
+-------------+--------------------------+----------+
| Brand Nine | 3 | 3 |
| Brand Ten | 2 | 3 |
| Brand One | 2 | 2 |
| Brand Seven | 2 | 2 |
| Brand Three | 3 | 3 |
| Brand Two | 1 | 1 |
| Brand Six | 1 | 1 |
| Brand Four | 4 | 5 |
+-------------+--------------------------+----------+
8 rows in set (0.00 sec)Facets can aggregate over expressions. A classic example is the segmentation of prices by specific ranges:
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SELECT * FROM facetdemo FACET INTERVAL(price,200,400,600,800) AS price_range ;+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+-------------+
| id | price | brand_id | title | brand_name | property | j | categories | price_range |
+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+-------------+
| 1 | 306 | 1 | Product Ten Three | Brand One | Six_Ten | {"prop1":66,"prop2":91,"prop3":"One"} | 10,11 | 1 |
...
+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+-------------+
20 rows in set (0.00 sec)
+-------------+----------+
| price_range | count(*) |
+-------------+----------+
| 0 | 1885 |
| 3 | 1973 |
| 4 | 2100 |
| 2 | 1999 |
| 1 | 2043 |
+-------------+----------+
5 rows in set (0.01 sec)Facets can aggregate over multi-level grouping, with the result set being the same as if the query performed a multi-level grouping:
- SQL
SELECT *,INTERVAL(price,200,400,600,800) AS price_range FROM facetdemo
FACET price_range AS price_range,brand_name ORDER BY brand_name asc;+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+-------------+
| id | price | brand_id | title | brand_name | property | j | categories | price_range |
+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+-------------+
| 1 | 306 | 1 | Product Ten Three | Brand One | Six_Ten | {"prop1":66,"prop2":91,"prop3":"One"} | 10,11 | 1 |
...
+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+-------------+
20 rows in set (0.00 sec)
+--------------+-------------+----------+
| fprice_range | brand_name | count(*) |
+--------------+-------------+----------+
| 1 | Brand Eight | 197 |
| 4 | Brand Eight | 235 |
| 3 | Brand Eight | 203 |
| 2 | Brand Eight | 201 |
| 0 | Brand Eight | 197 |
| 4 | Brand Five | 230 |
| 2 | Brand Five | 197 |
| 1 | Brand Five | 204 |
| 3 | Brand Five | 193 |
| 0 | Brand Five | 183 |
| 1 | Brand Four | 195 |
...Facets can aggregate over histogram values by constructing fixed-size buckets over the values. The key function is:
key_of_the_bucket = interval + offset * floor ( ( value - offset ) / interval )The histogram argument interval must be positive, and the histogram argument offset must be positive and less than interval. By default, the buckets are returned as an array. The histogram argument keyed makes the response a dictionary with the bucket keys.
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- JSON 2
SELECT COUNT(*), HISTOGRAM(price, {hist_interval=100}) as price_range FROM facets GROUP BY price_range ORDER BY price_range ASC;+----------+-------------+
| count(*) | price_range |
+----------+-------------+
| 5 | 0 |
| 5 | 100 |
| 1 | 300 |
| 4 | 400 |
| 1 | 500 |
| 3 | 700 |
| 1 | 900 |
+----------+-------------+Facets can aggregate over histogram date values, which is similar to the normal histogram. The difference is that the interval is specified using a date or time expression. Such expressions require special support because the intervals are not always of fixed length. Values are rounded to the closest bucket using the following key function:
key_of_the_bucket = interval * floor ( value / interval )The histogram parameter calendar_interval understands months to have different amounts of days.
Unlike calendar_interval, the fixed_interval parameter uses a fixed number of units and does not deviate, regardless of where it falls on the calendar. However fixed_interval cannot process units such as months because a month is not a fixed quantity. Attempting to specify units like weeks or months for fixed_interval will result in an error.
The accepted intervals are described in the date_histogram expression. By default, the buckets are returned as an array. The histogram argument keyed makes the response a dictionary with the bucket keys.
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SELECT count(*), DATE_HISTOGRAM(tm, {calendar_interval='month'}) AS months FROM idx_dates GROUP BY months ORDER BY months ASC+----------+------------+
| count(*) | months |
+----------+------------+
| 442 | 1485907200 |
| 744 | 1488326400 |
| 720 | 1491004800 |
| 230 | 1493596800 |
+----------+------------+Facets can aggregate over a set of ranges. The values are checked against the bucket range, where each bucket includes the from value and excludes the to value from the range.
Setting the keyed property to true makes the response a dictionary with the bucket keys rather than an array.
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- JSON 2
SELECT COUNT(*), RANGE(price, {range_to=150},{range_from=150,range_to=300},{range_from=300}) price_range FROM facets GROUP BY price_range ORDER BY price_range ASC;+----------+-------------+
| count(*) | price_range |
+----------+-------------+
| 8 | 0 |
| 2 | 1 |
| 10 | 2 |
+----------+-------------+Facets can aggregate over a set of date ranges, which is similar to the normal range. The difference is that the from and to values can be expressed in Date math expressions. This aggregation includes the from value and excludes the to value for each range. Setting the keyed property to true makes the response a dictionary with the bucket keys rather than an array.
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SELECT COUNT(*), DATE_RANGE(tm, {range_to='2017||+2M/M'},{range_from='2017||+2M/M',range_to='2017||+5M/M'},{range_from='2017||+5M/M'}) AS points FROM idx_dates GROUP BY points ORDER BY points ASC;+----------+--------+
| count(*) | points |
+----------+--------+
| 442 | 0 |
| 1464 | 1 |
| 230 | 2 |
+----------+--------+Facets support the ORDER BY clause just like a standard query. Each facet can have its own ordering, and the facet ordering doesn't affect the main result set's ordering, which is determined by the main query's ORDER BY. Sorting can be done on attribute name, count (using COUNT(*), COUNT(DISTINCT attribute_name)), or the special FACET() function, which provides the aggregated data values. By default, a query with ORDER BY COUNT(*) will sort in descending order.
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SELECT * FROM facetdemo
FACET brand_name BY brand_id ORDER BY FACET() ASC
FACET brand_name BY brand_id ORDER BY brand_name ASC
FACET brand_name BY brand_id order BY COUNT(*) DESC;
FACET brand_name BY brand_id order BY COUNT(*);+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+
| id | price | brand_id | title | brand_name | property | j | categories |
+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+
| 1 | 306 | 1 | Product Ten Three | Brand One | Six_Ten | {"prop1":66,"prop2":91,"prop3":"One"} | 10,11 |
...
| 20 | 31 | 9 | Product Four One | Brand Nine | Ten_Four | {"prop1":79,"prop2":42,"prop3":"One"} | 12,13,14 |
+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+
20 rows in set (0.01 sec)
+-------------+----------+
| brand_name | count(*) |
+-------------+----------+
| Brand One | 1013 |
| Brand Two | 990 |
| Brand Three | 1016 |
| Brand Four | 994 |
| Brand Five | 1007 |
| Brand Six | 1039 |
| Brand Seven | 965 |
| Brand Eight | 1033 |
| Brand Nine | 944 |
| Brand Ten | 998 |
+-------------+----------+
10 rows in set (0.01 sec)
+-------------+----------+
| brand_name | count(*) |
+-------------+----------+
| Brand Eight | 1033 |
| Brand Five | 1007 |
| Brand Four | 994 |
| Brand Nine | 944 |
| Brand One | 1013 |
| Brand Seven | 965 |
| Brand Six | 1039 |
| Brand Ten | 998 |
| Brand Three | 1016 |
| Brand Two | 990 |
+-------------+----------+
10 rows in set (0.01 sec)
+-------------+----------+
| brand_name | count(*) |
+-------------+----------+
| Brand Six | 1039 |
| Brand Eight | 1033 |
| Brand Three | 1016 |
| Brand One | 1013 |
| Brand Five | 1007 |
| Brand Ten | 998 |
| Brand Four | 994 |
| Brand Two | 990 |
| Brand Seven | 965 |
| Brand Nine | 944 |
+-------------+----------+
10 rows in set (0.01 sec)By default, each facet result set is limited to 20 values. The number of facet values can be controlled with the LIMIT clause individually for each facet by providing either a number of values to return in the format LIMIT count or with an offset as LIMIT offset, count.
The maximum facet values that can be returned is limited by the query's max_matches setting. If you want to implement dynamic max_matches (limiting max_matches to offset + per page for better performance), it must be taken into account that a too low max_matches value can affect the number of facet values. In this case, a minimum max_matches value should be used that is sufficient to cover the number of facet values.
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SELECT * FROM facetdemo
FACET brand_name BY brand_id ORDER BY FACET() ASC LIMIT 0,1
FACET brand_name BY brand_id ORDER BY brand_name ASC LIMIT 2,4
FACET brand_name BY brand_id order BY COUNT(*) DESC LIMIT 4;+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+
| id | price | brand_id | title | brand_name | property | j | categories |
+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+
| 1 | 306 | 1 | Product Ten Three | Brand One | Six_Ten | {"prop1":66,"prop2":91,"prop3":"One"} | 10,11 |
...
| 20 | 31 | 9 | Product Four One | Brand Nine | Ten_Four | {"prop1":79,"prop2":42,"prop3":"One"} | 12,13,14 |
+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+
20 rows in set (0.01 sec)
+-------------+----------+
| brand_name | count(*) |
+-------------+----------+
| Brand One | 1013 |
+-------------+----------+
1 rows in set (0.01 sec)
+-------------+----------+
| brand_name | count(*) |
+-------------+----------+
| Brand Four | 994 |
| Brand Nine | 944 |
| Brand One | 1013 |
| Brand Seven | 965 |
+-------------+----------+
4 rows in set (0.01 sec)
+-------------+----------+
| brand_name | count(*) |
+-------------+----------+
| Brand Six | 1039 |
| Brand Eight | 1033 |
| Brand Three | 1016 |
+-------------+----------+
3 rows in set (0.01 sec)When using SQL, a search with facets returns multiple result sets. The MySQL client/library/connector used must support multiple result sets in order to access the facet result sets.
Internally, the FACET is a shorthand for executing a multi-query where the first query contains the main search query and the rest of the queries in the batch have each a clustering. As in the case of multi-query, the common query optimization can kick in for a faceted search, meaning the search query is executed only once, and the facets operate on the search query result, with each facet adding only a fraction of time to the total query time.
To check if the faceted search ran in an optimized mode, you can look in the query log, where all logged queries will contain an xN string, where N is the number of queries that ran in the optimized group. Alternatively, you can check the output of the SHOW META statement, which will display a multiplier metric:
- SQL
SELECT * FROM facetdemo FACET brand_id FACET price FACET categories;
SHOW META LIKE 'multiplier';+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+
| id | price | brand_id | title | brand_name | property | j | categories |
+------+-------+----------+---------------------+-------------+-------------+---------------------------------------+------------+
| 1 | 306 | 1 | Product Ten Three | Brand One | Six_Ten | {"prop1":66,"prop2":91,"prop3":"One"} | 10,11 |
...
+----------+----------+
| brand_id | count(*) |
+----------+----------+
| 1 | 1013 |
...
+-------+----------+
| price | count(*) |
+-------+----------+
| 306 | 7 |
...
+------------+----------+
| categories | count(*) |
+------------+----------+
| 10 | 2436 |
...
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| multiplier | 4 |
+---------------+-------+
1 row in set (0.00 sec)One of the greatest features of Manticore Search is the ability to combine full-text searching with geo-location. For example, a retailer can offer a search where a user looks for a product, and the result set can indicate the closest shop that has the product in stock, so the user can go in-store and pick it up. A travel site can provide results based on a search limited to a certain area and have the results sorted by the distance from a point (for example, 'search museums near a hotel').
To perform geo-searching, a document needs to contain pairs of latitude/longitude coordinates. The coordinates can be stored as float attributes. If the document has multiple locations, it may be convenient to use a JSON attribute to store coordinate pairs.
table myrt
{
...
rt_attr_float = lat
rt_attr_float = lon
...
}The coordinates can be stored as degrees or radians.
If secondary indexes are generated for latitude and longitude attributes, they may automatically be used to speed up geo searches if the Cost based optimizer decides to use them.
To find out the distance between two points, the GEODIST() function can be used. GEODIST requires two pairs of coordinates as its first four parameters.
The 5th parameter in a simplified JSON format can configure certain aspects of the function. By default, GEODIST expects coordinates to be in radians, but in=degrees can be added to allow using degrees as input. The coordinates for which we perform the geo distance must have the same type (degrees or radians) as the ones stored in the table; otherwise, results will be misleading.
The calculated distance is by default in meters, but with the out option, it can be transformed to kilometers, feet, or miles. Lastly, by default, a calculation method called adaptive is used. An alternative method based on the haversine algorithm is available; however, this one is slower and less precise.
The result of the function - the distance - can be used in theORDER BY clause to sort the results:
SELECT *, GEODIST(40.7643929, -73.9997683, lat, lon, {in=degrees, out=miles}) AS distance FROM myindex WHERE MATCH('...') ORDER BY distance ASC, WEIGHT() DESC;Or to limit the results to a radial area around the point:
SELECT *,GEODIST(40.7643929, -73.9997683, lat,lon, {in=degrees, out=miles}) AS distance FROM myindex WHERE MATCH('...') AND distance <1000 ORDER BY WEIGHT(), DISTANCE ASC;Another geo search feature is the ability to determine if a location is within a specified area. A special function constructs a polygon object, which is then used by another function to test whether a set of coordinates is contained within that polygon or not.
There are two functions available for creating the polygon:
- GEOPOLY2D() - creates a polygon that takes into account the Earth's curvature
- POLY2D() - creates a simple polygon in flat space
POLY2D is suitable for geo searches when the area has sides shorter than 500km (for polygons with 3-4 sides; for polygons with more sides, lower values should be considered). For areas with longer sides, using GEOPOLY2D is required to maintain accurate results. GEOPOLY2D expects coordinates as latitude/longitude pairs in degrees; using radians will yield results in flat space (similar to POLY2D).
CONTAINS() takes a polygon and a set of coordinates as input and outputs 1 if the point is inside the polygon or 0 otherwise.
SELECT *,CONTAINS(GEOPOLY2D(40.76439, -73.9997, 42.21211, -73.999, 42.21211, -76.123, 40.76439, -76.123), 41.5445, -74.973) AS inside FROM myindex WHERE MATCH('...') AND inside=1;Percolate queries are also known as Persistent queries, Prospective search, document routing, search in reverse, and inverse search.
The traditional way of conducting searches involves storing documents and performing search queries against them. However, there are cases where we want to apply a query to a newly incoming document to signal a match. Some scenarios where this is desired include monitoring systems that collect data and notify users about specific events, such as reaching a certain threshold for a metric or a particular value appearing in the monitored data. Another example is news aggregation, where users may want to be notified only about certain categories or topics, or even specific "keywords."
In these situations, traditional search is not the best fit, as it assumes the desired search is performed over the entire collection. This process gets multiplied by the number of users, resulting in many queries running over the entire collection, which can cause significant additional load. The alternative approach described in this section involves storing the queries instead and testing them against an incoming new document or a batch of documents.
Google Alerts, AlertHN, Bloomberg Terminal, and other systems that allow users to subscribe to specific content utilize similar technology.
- See percolate for information on creating a PQ table.
- See Adding rules to a percolate table to learn how to add percolate rules (also known as PQ rules). Here's a quick example:
The key thing to remember about percolate queries is that your search queries are already in the table. What you need to provide are documents to check if any of them match any of the stored rules.
You can perform a percolate query via SQL or JSON interfaces, as well as using programming language clients. The SQL approach offers more flexibility, while the HTTP method is simpler and provides most of what you need. The table below can help you understand the differences.
| Desired Behavior | SQL | HTTP |
|---|---|---|
| Provide a single document | CALL PQ('tbl', '{doc1}') |
query.percolate.document{doc1} |
| Provide a single document (alternative) | CALL PQ('tbl', 'doc1', 0 as docs_json) |
- |
| Provide multiple documents | CALL PQ('tbl', ('doc1', 'doc2'), 0 as docs_json) |
- |
| Provide multiple documents (alternative) | CALL PQ('tbl', ('{doc1}', '{doc2}')) |
- |
| Provide multiple documents (alternative) | CALL PQ('tbl', '[{doc1}, {doc2}]') |
- |
| Return matching document ids | 0/1 as docs (disabled by default) | Enabled by default |
| Use document's own id to show in the result | 'id field' as docs_id (disabled by default) | Not available |
| Consider input documents are JSON | 1 as docs_json (1 by default) | Enabled by default |
| Consider input documents are plain text | 0 as docs_json (1 by default) | Not available |
| Sparsed distribution mode | default | default |
| Sharded distribution mode | sharded as mode | Not available |
| Return all info about matching query | 1 as query (0 by default) | Enabled by default |
| Skip invalid JSON | 1 as skip_bad_json (0 by default) | Not available |
| Extended info in SHOW META | 1 as verbose (0 by default) | Not available |
| Define the number which will be added to document ids if no docs_id fields provided (mostly relevant in distributed PQ modes) | 1 as shift (0 by default) | Not available |
To demonstrate how this works, here are a few examples. Let's create a PQ table with two fields:
- title (text)
- color (string)
and three rules in it:
- Just full-text. Query:
@title bag - Full-text and filtering. Query:
@title shoes. Filters:color='red' - Full-text and more complex filtering. Query:
@title shoes. Filters:color IN('blue', 'green')
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CREATE TABLE products(title text, color string) type='pq';
INSERT INTO products(query) values('@title bag');
INSERT INTO products(query,filters) values('@title shoes', 'color=\'red\'');
INSERT INTO products(query,filters) values('@title shoes', 'color in (\'blue\', \'green\')');
select * from products;+---------------------+--------------+------+---------------------------+
| id | query | tags | filters |
+---------------------+--------------+------+---------------------------+
| 1657852401006149635 | @title shoes | | color IN ('blue, 'green') |
| 1657852401006149636 | @title shoes | | color='red' |
| 1657852401006149637 | @title bag | | |
+---------------------+--------------+------+---------------------------+The first document doesn't match any rules. It could match the first two, but they require additional filters.
The second document matches one rule. Note that CALL PQ by default expects a document to be a JSON, but if you use 0 as docs_json, you can pass a plain string instead.
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CALL PQ('products', 'Beautiful shoes', 0 as docs_json);
CALL PQ('products', 'What a nice bag', 0 as docs_json);
CALL PQ('products', '{"title": "What a nice bag"}');+---------------------+
| id |
+---------------------+
| 1657852401006149637 |
+---------------------+
+---------------------+
| id |
+---------------------+
| 1657852401006149637 |
+---------------------+- SQL
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CALL PQ('products', '{"title": "What a nice bag"}', 1 as query);+---------------------+------------+------+---------+
| id | query | tags | filters |
+---------------------+------------+------+---------+
| 1657852401006149637 | @title bag | | |
+---------------------+------------+------+---------+Note that with CALL PQ, you can provide multiple documents in different ways:
- as an array of plain documents in round brackets
('doc1', 'doc2'). This requires0 as docs_json - as an array of JSONs in round brackets
('{doc1}', '{doc2}') - or as a standard JSON array
'[{doc1}, {doc2}]'
- SQL
- JSON
- PHP
- Python
- javascript
- Java
- C#
- TypeScript
- Go
CALL PQ('products', ('nice pair of shoes', 'beautiful bag'), 1 as query, 0 as docs_json);
CALL PQ('products', ('{"title": "nice pair of shoes", "color": "red"}', '{"title": "beautiful bag"}'), 1 as query);
CALL PQ('products', '[{"title": "nice pair of shoes", "color": "blue"}, {"title": "beautiful bag"}]', 1 as query);+---------------------+------------+------+---------+
| id | query | tags | filters |
+---------------------+------------+------+---------+
| 1657852401006149637 | @title bag | | |
+---------------------+------------+------+---------+
+---------------------+--------------+------+-------------+
| id | query | tags | filters |
+---------------------+--------------+------+-------------+
| 1657852401006149636 | @title shoes | | color='red' |
| 1657852401006149637 | @title bag | | |
+---------------------+--------------+------+-------------+
+---------------------+--------------+------+---------------------------+
| id | query | tags | filters |
+---------------------+--------------+------+---------------------------+
| 1657852401006149635 | @title shoes | | color IN ('blue, 'green') |
| 1657852401006149637 | @title bag | | |
+---------------------+--------------+------+---------------------------+Using the option 1 as docs allows you to see which documents of the provided ones match which rules.
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CALL PQ('products', '[{"title": "nice pair of shoes", "color": "blue"}, {"title": "beautiful bag"}]', 1 as query, 1 as docs);+---------------------+-----------+--------------+------+---------------------------+
| id | documents | query | tags | filters |
+---------------------+-----------+--------------+------+---------------------------+
| 1657852401006149635 | 1 | @title shoes | | color IN ('blue, 'green') |
| 1657852401006149637 | 2 | @title bag | | |
+---------------------+-----------+--------------+------+---------------------------+By default, matching document ids correspond to their relative numbers in the list you provide. However, in some cases, each document already has its own id. For this case, there's an option 'id field name' as docs_id for CALL PQ.
Note that if the id cannot be found by the provided field name, the PQ rule will not be shown in the results.
This option is only available for CALL PQ via SQL.
- SQL
CALL PQ('products', '[{"id": 123, "title": "nice pair of shoes", "color": "blue"}, {"id": 456, "title": "beautiful bag"}]', 1 as query, 'id' as docs_id, 1 as docs);+---------------------+-----------+--------------+------+---------------------------+
| id | documents | query | tags | filters |
+---------------------+-----------+--------------+------+---------------------------+
| 1657852401006149664 | 456 | @title bag | | |
| 1657852401006149666 | 123 | @title shoes | | color IN ('blue, 'green') |
+---------------------+-----------+--------------+------+---------------------------+When using CALL PQ with separate JSONs, you can use the option 1 as skip_bad_json to skip any invalid JSONs in the input. In the example below, the 2nd query fails due to an invalid JSON, but the 3rd query avoids the error by using 1 as skip_bad_json. Keep in mind that this option is not available when sending JSON queries over HTTP, as the whole JSON query must be valid in that case.
- SQL
CALL PQ('products', ('{"title": "nice pair of shoes", "color": "blue"}', '{"title": "beautiful bag"}'));
CALL PQ('products', ('{"title": "nice pair of shoes", "color": "blue"}', '{"title": "beautiful bag}'));
CALL PQ('products', ('{"title": "nice pair of shoes", "color": "blue"}', '{"title": "beautiful bag}'), 1 as skip_bad_json);+---------------------+
| id |
+---------------------+
| 1657852401006149635 |
| 1657852401006149637 |
+---------------------+
ERROR 1064 (42000): Bad JSON objects in strings: 2
+---------------------+
| id |
+---------------------+
| 1657852401006149635 |
+---------------------+Percolate queries are designed with high throughput and large data volumes in mind. To optimize performance for lower latency and higher throughput, consider the following.
There are two modes of distribution for a percolate table and how a percolate query can work against it:
- Sparse (default). Ideal for: many documents, mirrored PQ tables. When your document set is large but the set of queries stored in the PQ table is small, the sparse mode is beneficial. In this mode, the batch of documents you pass will be divided among the number of agents, so each node processes only a portion of the documents from your request. Manticore splits your document set and distributes chunks among the mirrors. Once the agents have finished processing the queries, Manticore collects and merges the results, returning a final query set as if it came from a single table. Use replication to assist the process.
- Sharded. Ideal for: many PQ rules, rules split among PQ tables. In this mode, the entire document set is broadcast to all tables of the distributed PQ table without initially splitting the documents. This is beneficial when pushing a relatively small set of documents, but the number of stored queries is large. In this case, it's more appropriate to store only a portion of PQ rules on each node and then merge the results returned from the nodes that process the same set of documents against different sets of PQ rules. This mode must be explicitly set, as it implies an increase in network payload and expects tables with different PQs, which replication cannot do out-of-the-box.
Assume you have table pq_d2 defined as:
table pq_d2
{
type = distributed
agent = 127.0.0.1:6712:pq
agent = 127.0.0.1:6712:ptitle
}Each of 'pq' and 'ptitle' contains:
- SQL
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SELECT * FROM pq;+------+-------------+------+-------------------+
| id | query | tags | filters |
+------+-------------+------+-------------------+
| 1 | filter test | | gid>=10 |
| 2 | angry | | gid>=10 OR gid<=3 |
+------+-------------+------+-------------------+
2 rows in set (0.01 sec)And you execute CALL PQ on the distributed table with a couple of documents.
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CALL PQ ('pq_d2', ('{"title":"angry test", "gid":3 }', '{"title":"filter test doc2", "gid":13}'), 1 AS docs);+------+-----------+
| id | documents |
+------+-----------+
| 1 | 2 |
| 2 | 1 |
+------+-----------+In the previous example, we used the default sparse mode. To demonstrate the sharded mode, let's create a distributed PQ table consisting of 2 local PQ tables and add 2 documents to "products1" and 1 document to "products2":
create table products1(title text, color string) type='pq';
create table products2(title text, color string) type='pq';
create table products_distributed type='distributed' local='products1' local='products2';
INSERT INTO products1(query) values('@title bag');
INSERT INTO products1(query,filters) values('@title shoes', 'color=\'red\'');
INSERT INTO products2(query,filters) values('@title shoes', 'color in (\'blue\', \'green\')');Now, if you add 'sharded' as mode to CALL PQ, it will send the documents to all the agent's tables (in this case, just local tables, but they can be remote to utilize external hardware). This mode is not available via the JSON interface.
- SQL
CALL PQ('products_distributed', ('{"title": "nice pair of shoes", "color": "blue"}', '{"title": "beautiful bag"}'), 'sharded' as mode, 1 as query);+---------------------+--------------+------+---------------------------+
| id | query | tags | filters |
+---------------------+--------------+------+---------------------------+
| 1657852401006149639 | @title bag | | |
| 1657852401006149643 | @title shoes | | color IN ('blue, 'green') |
+---------------------+--------------+------+---------------------------+Note that the syntax of agent mirrors in the configuration (when several hosts are assigned to one agent line, separated with |) has nothing to do with the CALL PQ query mode. Each agent always represents one node, regardless of the number of HA mirrors specified for that agent.
In some cases, you might want to get more details about the performance of a percolate query. For that purpose, there is the option 1 as verbose, which is only available via SQL and allows you to save more performance metrics. You can see them using the SHOW META query, which you can run after CALL PQ. See SHOW META for more info.
- 1 as verbose
- 0 as verbose
CALL PQ('products', ('{"title": "nice pair of shoes", "color": "blue"}', '{"title": "beautiful bag"}'), 1 as verbose); show meta;+---------------------+
| id |
+---------------------+
| 1657852401006149644 |
| 1657852401006149646 |
+---------------------+
+-------------------------+-----------+
| Name | Value |
+-------------------------+-----------+
| Total | 0.000 sec |
| Setup | 0.000 sec |
| Queries matched | 2 |
| Queries failed | 0 |
| Document matched | 2 |
| Total queries stored | 3 |
| Term only queries | 3 |
| Fast rejected queries | 0 |
| Time per query | 27, 10 |
| Time of matched queries | 37 |
+-------------------------+-----------+