Search index limits - Tablestore - Alibaba Cloud Documentation Center

Search indexes in Tablestore have limits on row count, data size, field count, read/write rate, synchronization latency, and query parameters.

Index limits

The following table lists the limits on row count, data size, field count, read/write rate, synchronization latency, nested fields, and data table fields for a search index.

Item	Value	Description
Number of search indexes	No limit	Create only one search index that contains all required fields.
Number of rows	1 trillion	If your business requirements exceed the limit, please submit a ticket to contact us.
Total size	1 PB	If your business requirements exceed the limit, please submit a ticket to contact us.
Number of index fields	1000	If your business requirements exceed the limit, please submit a ticket to contact us.
Read and write rate	100,000 rows/s	Initial writes or burst writes trigger load balancing that takes a few minutes to complete. Maximum indexing throughput depends on field type and size. Throughput decreases for hot spots, large text fields, nested fields, or vector fields. If your business requirements exceed the limits, please submit a ticket to contact us.
Synchronization latency	3 seconds	In 99% of cases, the synchronization latency is within 3 seconds. For stricter latency requirements, submit a ticket to contact us. A new index requires up to 1 minute to initialize.
Array length	256	The maximum number of elements in an array.
Nested field limits	Unique within the search index	Supports up to 5 levels of nesting. Maximum of 256 child rows per nested field. Maximum of 100 subfields per nested field.
Vector field limits	5	A search index supports up to 5 vector fields. If your business requirements exceed this limit, please submit a ticket. Maximum dimension count per vector field: 4,096.
Total length of all primary key column values	1,000 bytes	The combined length of all primary key column values cannot exceed 1,000 bytes.
Length of a String value in a primary key column	1,000 bytes	A String-type primary key column value cannot exceed 1,000 bytes when indexed.
Length of a String value in an attribute column (indexed as Keyword)	4 KB	None.
Length of a String value in an attribute column (indexed as FuzzyKeyword)	2 KB	None.
Length of a String value in an attribute column (indexed as Text)	2 MB	Generally matches the attribute column length limit in the data table. When performing a fuzzy query on a Text field with fuzzy tokenization, only the first 1,024 characters are indexed. Content beyond this limit is truncated.

Query limits

Search API

The following table lists the limits when querying, aggregating, and analyzing data with the Search API.

Category	Item	Value	Description
General limits	offset+limit	100000	The limit parameter defaults to 10, with a maximum of 100.If your business requirements exceed the limit, please submit a ticket to contact us. When the search index contains the queried column data, the limit parameter supports up to 1,000, allowing a single request to return up to 1,000 results. To retrieve more results, use the next_token parameter for pagination.
	timeout	10 seconds	None.
	CU	No limit	None.
	QPS	100,000	For lightweight transaction processing (TP) queries, the QPS upper limit is 100,000. If your business requirements exceed the limit, please submit a ticket to contact us.
	Number of queries in a single Search request	1,024	Overly complex nested queries reduce performance. Simplify queries for better efficiency.
Terms query	Number of search terms	1,024	A terms query supports a maximum of 1,024 search terms.
Wildcard query	Search query length	32 characters	The search query for a WildcardQuery cannot exceed 32 characters.
Prefix query	Search query length	1,000 characters	The search query for a PrefixQuery cannot exceed 1,000 characters.
Full-text search	Total number of highlighted fragments	500	Maximum total highlighted fragments across all inner_hits and highlight results in a single request.
Full-text search	Number of highlighted fields	10	Highlight parameters can be specified for up to 10 fields.
Vector search	Number of top K rows returned	1,000	A KnnVectorQuery returns at most the top 1,000 rows.
Aggregation	Number of Aggregations at the same level	32	The count resets to 0 when an Aggregation is added to a SubGroupBy.
	Number of GroupBys at the same level	5	The count resets to 0 when a GroupBy is added to a SubGroupBy.
	GroupBy nesting levels	3	The level count includes the GroupBy itself. Maximum nesting depth is 3.
	Number of Filters in GroupByFilter	10	None.
	Number of groups returned by GroupByField	2,000	None.
	Number of internal sources in GroupByComposite	32	Maximum number of columns for multi-column grouping.
	Number of Ranges in GroupByRange	100	None.
	Number of Ranges in GroupByGeodistance	10	None.

ParallelScan API

The following table lists the limits when querying data and performing parallel scans with the ParallelScan API.

Category	Item	Value	Description
General limits	offset+limit	Not supported	The offset and limit parameters are not supported. Data traversal starts from the beginning only. The maximum value of the limit parameter is 2000.
	CU	No limit	None.
	QPS	No limit	None.
Parallel data export	Maximum concurrency	Equal to the MaxParallel value	Determined by the MaxParallel value returned by the ComputeSplits API.
	Task validity period (aliveTime)	10 minutes	None.
	Concurrent ParallelScan tasks	10	Concurrent tasks that have the same session ID and ScanQuery are considered a single task. For more information, see parallel scan.