21.2.7.5 Limits Associated with Database Objects in NDB Cluster
Some database objects such as tables and indexes have different limitations when using the NDBCLUSTER storage engine:
Database and table names. When using the
NDBstorage engine, the maximum allowed length both for database names and for table names is 63 characters. A statement using a database name or table name longer than this limit fails with an appropriate error.Number of database objects. The maximum number of all
NDBdatabase objects in a single NDB Cluster—including databases, tables, and indexes—is limited to 20320.Attributes per table. The maximum number of attributes (that is, columns and indexes) that can belong to a given table is 512.
Attributes per key. The maximum number of attributes per key is 32.
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Row size. The maximum permitted size of any one row is 14000 bytes.
Each
BLOBorTEXTcolumn contributes 256 + 8 = 264 bytes to this total; this includesJSONcolumns. See String Type Storage Requirements, as well as JSON Storage Requirements, for more information relating to these types.In addition, the maximum offset for a fixed-width column of an
NDBtable is 8188 bytes; attempting to create a table that violates this limitation fails with NDB error 851 Maximum offset for fixed-size columns exceeded. For memory-based columns, you can work around this limitation by using a variable-width column type such asVARCHARor defining the column asCOLUMN_FORMAT=DYNAMIC; this does not work with columns stored on disk. For disk-based columns, you may be able to do so by reordering one or more of the table's disk-based columns such that the combined width of all but the disk-based column defined last in theCREATE TABLEstatement used to create the table does not exceed 8188 bytes, less any possible rounding performed for some data types such asCHARorVARCHAR; otherwise it is necessary to use memory-based storage for one or more of the offending column or columns instead. BIT column storage per table. The maximum combined width for all
BITcolumns used in a givenNDBtable is 4096.FIXED column storage. NDB Cluster 7.5 and later supports a maximum of 128 TB per fragment of data in
FIXEDcolumns. (Previously, this was 16 GB.)
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