diff --git a/ndb/docs/doxygen/Doxyfile.ndb b/ndb/docs/doxygen/Doxyfile.ndb index c823c638c9f..3986a7cd17f 100644 --- a/ndb/docs/doxygen/Doxyfile.ndb +++ b/ndb/docs/doxygen/Doxyfile.ndb @@ -14,6 +14,8 @@ # General configuration options #--------------------------------------------------------------------------- +DETAILS_AT_TOP = YES + # The PROJECT_NAME tag is a single word (or a sequence of words surrounded # by quotes) that should identify the project. diff --git a/ndb/docs/doxygen/Doxyfile.ndbapi b/ndb/docs/doxygen/Doxyfile.ndbapi index 72280574888..da610148468 100644 --- a/ndb/docs/doxygen/Doxyfile.ndbapi +++ b/ndb/docs/doxygen/Doxyfile.ndbapi @@ -13,8 +13,8 @@ #--------------------------------------------------------------------------- # General configuration options #--------------------------------------------------------------------------- -DETAILS_AT_TOP = yes -HIDE_FRIEND_COMPOUNDS = yes +DETAILS_AT_TOP = YES +HIDE_FRIEND_COMPOUNDS = YES # The PROJECT_NAME tag is a single word (or a sequence of words surrounded # by quotes) that should identify the project. diff --git a/ndb/docs/doxygen/Doxyfile.odbc b/ndb/docs/doxygen/Doxyfile.odbc index 382ee53b836..262513852b7 100644 --- a/ndb/docs/doxygen/Doxyfile.odbc +++ b/ndb/docs/doxygen/Doxyfile.odbc @@ -14,6 +14,8 @@ # General configuration options #--------------------------------------------------------------------------- +DETAILS_AT_TOP = YES + # The PROJECT_NAME tag is a single word (or a sequence of words surrounded # by quotes) that should identify the project. diff --git a/ndb/docs/doxygen/Doxyfile.test b/ndb/docs/doxygen/Doxyfile.test index 1051dbc1d3a..801c82cf380 100644 --- a/ndb/docs/doxygen/Doxyfile.test +++ b/ndb/docs/doxygen/Doxyfile.test @@ -14,6 +14,8 @@ # General configuration options #--------------------------------------------------------------------------- +DETAILS_AT_TOP = YES + # The PROJECT_NAME tag is a single word (or a sequence of words surrounded # by quotes) that should identify the project. diff --git a/ndb/include/ndbapi/Ndb.hpp b/ndb/include/ndbapi/Ndb.hpp index 39ec90937a4..10b939b50f5 100644 --- a/ndb/include/ndbapi/Ndb.hpp +++ b/ndb/include/ndbapi/Ndb.hpp @@ -538,64 +538,69 @@ #endif /** - @page secConcepts NDB Cluster Concepts + @page secConcepts MySQL Cluster Concepts The NDB Kernel is the collection of storage nodes - belonging to an NDB Cluster. + belonging to a MySQL Cluster. The application programmer can for most purposes view the - set of all DB nodes as one entity. - Each DB node has three main components: - - TC : The transaction coordinator - - ACC : The index storage - - TUP : The data storage + set of all storage nodes as a single entity. + Each storage node is made up of three main components: + - TC : The transaction co-ordinator + - ACC : Index storage component + - TUP : Data storage component - When the application program executes a transaction, - it connects to one TC on one DB node. - Usually, the programmer does not need to specify which TC to use, - but some cases when performance is important, - transactions can be hinted to use a certain TC. - (If the node with the TC is down, then another TC will + When an application program executes a transaction, + it connects to one transaction co-ordinator on one storage node. + Usually, the programmer does not need to specify which TC should be used, + but in some cases when performance is important, the programmer can + provide "hints" to use a certain TC. + (If the node with the desired transaction co-ordinator is down, then another TC will automatically take over the work.) - Every DB node has an ACC and a TUP which stores - the index and the data part of the database. + Every storage node has an ACC and a TUP which store + the indexes and data portions of the database table fragment. Even though one TC is responsible for the transaction, - several ACCs and TUPs on other DB nodes might be involved in the + several ACCs and TUPs on other storage nodes might be involved in the execution of the transaction. - @section secNdbKernelConnection Selecting Transaction Coordinator + @section secNdbKernelConnection Selecting a Transaction Co-ordinator - The default method is to select the transaction coordinator (TC) as being - the "closest" DB node. There is a heuristics for closeness based on - the type of transporter connection. In order of closest first, we have - SCI, SHM, TCP/IP (localhost), and TCP/IP (remote host). If there are several - connections available with the same "closeness", they will each be + The default method is to select the transaction co-ordinator (TC) determined to be + the "closest" storage node, using a heuristic for proximity based on + the type of transporter connection. In order of closest to most distant, these are + - SCI + - SHM + - TCP/IP (localhost) + - TCP/IP (remote host) + If there are several connections available with the same proximity, they will each be selected in a round robin fashion for every transaction. Optionally - one may set the methos for TC selection round robin over all available - connections, where each new set of transactions - is placed on the next DB node. + one may set the method for TC selection to round-robin mode, where each new set of + transactions is placed on the next DB node. The pool of connections from which this + selection is made consists of all available connections. - The application programmer can however hint the NDB API which - transaction coordinator to use - by providing a partition key (usually the primary key). - By using the primary key as partition key, + As noted previously, the application programmer can provide hints to the NDB API as to + which transaction co-ordinator it should use. This is done by + providing a partition key (usually the primary key). + By using the primary key as the partition key, the transaction will be placed on the node where the primary replica of that record resides. - Note that this is only a hint, the system can be - reconfigured and then the NDB API will choose a transaction - coordinator without using the hint. - For more information, see NdbDictionary::Column::getPartitionKey(), - Ndb::startTransaction(). The application programmer can specify + Note that this is only a hint; the system can be + reconfigured at any time, in which case the NDB API will choose a transaction + co-ordinator without using the hint. + For more information, see NdbDictionary::Column::getPartitionKey() and + Ndb::startTransaction(). The application programmer can specify the partition key from SQL by using the construct, - "CREATE TABLE ... ENGINE=NDB PARTITION BY KEY ()". + CREATE TABLE ... ENGINE=NDB PARTITION BY KEY (attribute-list);. - @section secRecordStruct Record Structure - NDB Cluster is a relational database with tables of records. - Table rows represent tuples of relational data stored as records. - When created, the attribute schema of the table is specified, - and thus each record of the table has the same schema. + @section secRecordStruct NDB Record Structure + The NDB Cluster engine used by MySQL Cluster is a relational database engine + storing records in tables just as with any other RDBMS. + Table rows represent records as tuples of relational data. + When a new table is created, its attribute schema is specified for the table as a whole, + and thus each record of the table has the same structure. Again, this is typical + of relational databases, and NDB is no different in this regard. @subsection secKeys Primary Keys @@ -604,14 +609,14 @@ @section secTrans Transactions - Transactions are committed to main memory, - and are committed to disk after a global checkpoint, GCP. + Transactions are committed first to main memory, + and then to disk after a global checkpoint (GCP) is issued. Since all data is (in most NDB Cluster configurations) synchronously replicated and stored on multiple NDB nodes, the system can still handle processor failures without loss of data. However, in the case of a system failure (e.g. the whole system goes down), - then all (committed or not) transactions after the latest GCP are lost. + then all (committed or not) transactions occurring since the latest GCP are lost. @subsection secConcur Concurrency Control @@ -620,39 +625,38 @@ cannot be attained within a specified time, then a timeout error occurs. - Concurrent transactions (parallel application programs, thread-based - applications) - sometimes deadlock when they try to access the same information. - Applications need to be programmed so that timeout errors - occurring due to deadlocks are handled. This generally - means that the transaction encountering timeout - should be rolled back and restarted. + Concurrent transactions as requested by parallel application programs and + thread-based applications can sometimes deadlock when they try to access + the same information simultaneously. + Thus, applications need to be written in a manner so that timeout errors + occurring due to such deadlocks are handled gracefully. This generally + means that the transaction encountering a timeout should be rolled back + and restarted. - @section secHint Hints and performance + @section secHint Hints and Performance - Placing the transaction coordinator close + Placing the transaction co-ordinator in close proximity to the actual data used in the transaction can in many cases improve performance significantly. This is particularly true for - systems using TCP/IP. A system using Solaris and a 500 MHz processor - has a cost model for TCP/IP communication which is: + systems using TCP/IP. For example, a Solaris system using a single 500 MHz processor + has a cost model for TCP/IP communication which can be represented by the formula - 30 microseconds + (100 nanoseconds * no of Bytes) + [30 microseconds] + ([100 nanoseconds] * [number of bytes]) This means that if we can ensure that we use "popular" links we increase buffering and thus drastically reduce the communication cost. - Systems using SCI has a different cost model which is: + The same system using SCI has a different cost model: - 5 microseconds + (10 nanoseconds * no of Bytes) + [5 microseconds] + ([10 nanoseconds] * [number of bytes]) - Thus SCI systems are much less dependent on selection of - transaction coordinators. - Typically TCP/IP systems spend 30-60% of the time during communication, - whereas SCI systems typically spend 5-10% of the time during - communication. - Thus SCI means that less care from the NDB API programmer is - needed and great scalability can be achieved even for applications using - data from many parts of the database. + Thus, the efficiency of an SCI system is much less dependent on selection of + transaction co-ordinators. + Typically, TCP/IP systems spend 30-60% of their working time on communication, + whereas for SCI systems this figure is closer to 5-10%. + Thus, employing SCI for data transport means that less care from the NDB API + programmer is required and greater scalability can be achieved, even for + applications using data from many different parts of the database. A simple example is an application that uses many simple updates where a transaction needs to update one record. @@ -928,11 +932,11 @@ i.e. get/setValue("kalle[3]"); @subsection secArrays Array Attributes - A table attribute in NDB Cluster can be of array type. - This means that the attribute consists of an array of - elements. The attribute size is the size - of one element of the array (expressed in bits) and the - array size is the number of elements of the array. + A table attribute in NDB Cluster can be of type Array, + meaning that the attribute consists of an ordered sequence of + elements. In such cases, attribute size is the size + (expressed in bits) of any one element making up the array; the + array size is the number of elements in the array. */ @@ -1051,16 +1055,16 @@ public: /** * The Ndb object represents a connection to a database. * - * @note the init() method must be called before it may be used + * @note The init() method must be called before the Ndb object may actually be used. * - * @param ndb_cluster_connection is a connection to a cluster containing + * @param ndb_cluster_connection is a connection to the cluster containing * the database to be used - * @param aCatalogName is the name of the catalog you want to use. - * @note The catalog name provides a name space for the tables and + * @param aCatalogName is the name of the catalog to be used. + * @note The catalog name provides a namespace for the tables and * indexes created in any connection from the Ndb object. * @param aSchemaName is the name of the schema you * want to use. - * @note The schema name provides an additional name space + * @note The schema name provides an additional namespace * for the tables and indexes created in a given catalog. */ Ndb(Ndb_cluster_connection *ndb_cluster_connection,