-|_. Operator|_. Operand type|_. Example|
-|@<@, @<=@, @>=@, @>@, @like@, @ilike@|string|@["script_version","like","d00220fb%"]@|
-|@=@, @!=@|string or null|@["tail_uuid","=","xyzzy-j7d0g-fffffffffffffff"]@
-@["tail_uuid","!=",null]@|
-|@in@, @not in@|array of strings|@["script_version","in",["master","d00220fb38d4b85ca8fc28a8151702a2b9d1dec5"]]@|
-|@is_a@|string|@["head_uuid","is_a","arvados#pipelineInstance"]@|
+|_. Operator|_. Operand type|_. Description|_. Example|
+|@=@, @!=@|string, number, timestamp, or null|Equality comparison|@["tail_uuid","=","xyzzy-j7d0g-fffffffffffffff"]@ @["tail_uuid","!=",null]@|
+|@<@, @<=@, @>=@, @>@|string, number, or timestamp|Ordering comparison|@["script_version",">","123"]@|
+|@like@, @ilike@|string|SQL pattern match. Single character match is @_@ and wildcard is @%@. The @ilike@ operator is case-insensitive|@["script_version","like","d00220fb%"]@|
+|@in@, @not in@|array of strings|Set membership|@["script_version","in",["main","d00220fb38d4b85ca8fc28a8151702a2b9d1dec5"]]@|
+|@is_a@|string|Arvados object type|@["head_uuid","is_a","arvados#collection"]@|
+|@exists@|string|Test if a subproperty is present.|@["properties","exists","my_subproperty"]@|
+
+h4(#substringsearchfilter). Filtering using substring search
+
+Resources can also be filtered by searching for a substring in attributes of type @string@, @array of strings@, @text@, and @hash@, which are indexed in the database specifically for search. To use substring search, the filter must:
+
+* Specify @any@ as the attribute
+* Use either the @like@ or @ilike@ operator
+* Have an operand of type @string@ that is wrapped in the SQL pattern match wildcard character @%@
+
+For example, the @["any", "like", "%foo%"]@ filter will return all resources that contain @foo@ in the content of at least one attribute of the previously defined types. This is the recommended way to do keyword and file name search across the entire database. Note that only exact substring matches are returned and results are unranked and returned in the order specified by the @list@ @order@ argument.
+
+h4(#subpropertyfilters). Filtering on subproperties
+
+Some record types have an additional @properties@ attribute that allows recording and filtering on additional key-value pairs. To filter on a subproperty, the value in the @attribute@ position has the form @properties.user_property@. You may also use JSON-LD / RDF style URIs for property keys by enclosing them in @<...>@ for example @properties.<http://example.com/user_property>@. Alternately you may also provide a JSON-LD "@context" field, however at this time JSON-LD contexts are not interpreted by Arvados.
+
+table(table table-bordered table-condensed).
+|_. Operator|_. Operand type|_. Description|_. Example|
+|@=@, @!=@|string, number or boolean|Equality comparison|@["properties.my_subproperty", "=", "fizzy whizy sparkle pop"]@|
+|@<@, @<=@, @>=@, @>@|string or number|Ordering comparison|@["properties.my_subproperty", "<", 3]@|
+|@like@, @ilike@|string|SQL pattern match, single character match is @_@ and wildcard is @%@, ilike is case-insensitive|@["properties.my_subproperty", "like", "d00220fb%"]@|
+|@in@, @not in@|array of strings|Set membership|@["properties.my_subproperty", "in", ["fizz", "buzz"]]@|
+|@exists@|boolean|Test if a subproperty is present or not (determined by operand).|@["properties.my_subproperty", "exists", true]@|
+|@contains@|string, number|Filter where subproperty has a value either by exact match or value is element of subproperty list.|@["foo", "contains", "bar"]@ will find both @{"foo": "bar"}@ and @{"foo": ["bar", "baz"]}@.|
+
+Note that exclusion filters @!=@ and @not in@ will return records for which the property is not defined at all. To restrict filtering to records on which the subproperty is defined, combine with an @exists@ filter.
+
+h4. Federated listing
+
+Federated listing forwards a request to multiple clusters and combines the results. Currently only a very restricted form of the "list" method is supported.
+
+To query multiple clusters, the list request must:
+
+* Have filters only matching @[["uuid", "in", [...]]@ or @["uuid", "=", "..."]@
+* Specify @count=none@
+* Not specify @limit@, @offset@ or @order@
+* Not request more items than the maximum response size
+
+This form may be used to request a specific list of objects by uuid which are owned by multiple clusters.