@Statistics

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@Statistics

@Statistics — Returns statistics about the usage of the VoltDB database.

Synopsis

@Statistics String component, Integer delta-flag

Description

The @Statistics system procedure returns information about the VoltDB database. The second argument, component, specifies what aspect of VoltDB to return statistics about. The third argument, delta-flag, specifies whether statistics are reported from when the database started or since the last call to @Statistics where the flag was set.

If the delta-flag is set to zero, the system procedure returns statistics since the database started. If the delta-flag is non-zero, the system procedure returns statistics for the interval since the last time @Statistics was called with a non-zero flag. (If @Statistics has not been called with a non-zero flag before, the first call with the flag set returns statistics since startup.)

Note that in a cluster with K-safety, if a node fails, the statistics reported by this procedure are reset to zero for the node when it rejoins the cluster.

The following are the allowable values of component:

"CPU"

Returns information about the amount of CPU used by each VoltDB server process. CPU usage is returned as a number between 0 and 100 representing the amount of CPU used by the VoltDB process out of the total CPU available for that server.

"DR"

Returns information about the status of database replication, including how much data is waiting to be sent to the DR agent. This information is available only if the database is licensed for database replication.

"INDEX"

Returns information about the indexes in the database, including the number of keys for each index and the estimated amount of memory used to store those keys. Separate information is returned for each partition in the database.

"INITIATOR"

Returns information on the number of procedure invocations for each stored procedure (including system procedures). The count of invocations is reported for each connection to the database.

"IOSTATS"

Returns information on the number of messages and amount of data (in bytes) sent to and from each connection to the database.

"LIVECLIENTS"

Returns information about the number of outstanding requests per client. You can use this information to determine how much work is waiting in the execution queues.

"MANAGEMENT"

Returns the same information as INDEX, INITIATOR, IOSTATS, MEMORY, PROCEDURE, and TABLE, except all in a single procedure call.

"MEMORY"

Returns statistics on the use of memory for each node in the cluster. MEMORY statistics include the current resident set size (RSS) of the VoltDB server process; the amount of memory used for Java temporary storage, database tables, indexes, and string (including varbinary) storage; as well as other information.

"PARTITIONCOUNT"

Returns information on the number of unique partitions in the cluster. The VoltDB cluster creates multiple partitions based on the number of servers and the number of sites per host requested. So, for example, a 2 node cluster with 4 sites per host will have 8 partitions. However, when you define a cluster with K-safety, there are duplicate partitions. PARTITIONCOUNT only reports the number of unique partitions available in the cluster.

"PLANNER"

Returns information on the use of cached plans within each partition. Queries in stored procedures are planned when the application catalog is compiled. However, ad hoc queries must be planned at runtime. To improve performance, VoltDB caches plans for ad hoc queries so they can be reused when a similar query is encountered later. There are two caches: the level 1 cache performs exact matches on queries and the level 2 cache parameterizes constants so it can match queries with the same plan but different input. The planner statistics provide information about the size of each cache, how frequently it is used, and the minimum, maximum, and average execution time of ad hoc queries as a result.

"PROCEDURE"

Returns information on the usage of stored procedures for each site within the database cluster sorted by partition. The information includes the name of the procedure, the number of invocations (for each site), and selected performance information on minimum, maximum, and average execution time.

"PROCEDUREINPUT"

Returns summary information on the size of the input data submitted with stored procedure invocations. PROCEDUREINPUT uses information from PROCEDURE, except it focuses on the input parameters and aggregates data for the entire cluster.

"PROCEDUREOUTPUT"

Returns summary information on the size of the result sets returned by stored procedure invocations. PROCEDUREOUTPUT uses information from PROCEDURE, except it focuses on the result sets and aggregates data for the entire cluster.

"PROCEDUREPROFILE"

Returns summary information on the usage of stored procedures averaged across all partitions in the cluster. The information from PROCEDUREPROFILE is similar to the information from PROCEDURE, except it focuses on the performance of the individual procedures rather than on procedures by partition. The weighted average across partitions is helpful for determining which stored procedures the application is spending most of its time in.

"REBALANCE"

Returns information on the current progress of rebalancing on the cluster. Rebalancing occurs when one or more nodes are added "on the fly" to an elastic cluster. If no rebalancing is occurring, no data is returned. During a rebalance, this selector returns information about the speed of migration of the data, the latency of rebalance tasks, and the estimated time until completion.

For rebalance, the delta flag to the system procedure is ignored. All rebalance statistics are cumulative for the current rebalance activity.

"SNAPSHOTSTATUS"

Returns information about up to ten of the most recent snapshots performed by the database. The results include the directory path and prefix for the snapshot, when it occurred, how long it took, and whether the snapshot was completed successfully or not. The results report on both native and CSV snapshots, as well as manual, automated, and command log snapshots. Note that this selector does not tell you whether the snapshot files still exist, only that the snapshot was performed. Use the @SnapshotScan procedure to determine what snapshots are available.

"TABLE"

Returns information about the database tables, including the number of rows per site for each table. This information can be useful for seeing how well the rows are distributed across the cluster for partitioned tables.

Note that INITIATOR and PROCEDURE report information on both user-declared stored procedures and system procedures. These include certain system procedures that are used internally by VoltDB and are not intended to be called by client applications. Only the system procedures documented in this appendix are intended for client invocation.

Return Values

Returns different VoltTables depending on which component is requested. The following tables identify the structure of the return values for each component. (Note that the MANAGEMENT component returns seven VoltTables.)

CPU — Returns a row for every server in the cluster.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
HOST_ID	INTEGER	Numeric ID for the host node.
HOSTNAME	STRING	Server name of the host node.
PERCENT_USED	BIGINT	The percentage of total CPU available used by the database server process.

DR — Returns two VoltTables. The first table contains information about the replication streams, which consist of a row per partition for each server. The data shows the current state of replication and how much data is currently queued for the DR agent.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
HOST_ID	INTEGER	Numeric ID for the host node.
HOSTNAME	STRING	Server name of the host node.
PARTITION_ID	INTEGER	The numeric ID for the logical partition.
STREAMTYPE	STRING	The type of stream, which can either be "TRANSACTIONS" or "SNAPSHOT".
TOTALBYTES	BIGINT	The total number of bytes currently queued for transmission to the DR agent.
TOTALBYTESINMEMORY	BIGINT	The total number of bytes of queued data currently held in memory. If the amount of total bytes is larger than the amount in memory, the remainder is kept in overflow storage on disk.
TOTALBUFFERS	BIGINT	The total number of buffers in this partition currently waiting for acknowledgement from the DR agent. Partitions create a buffer every five milliseconds.
LASTACKTIMESTAMP	BIGINT	The timestamp of the last acknowledgement received from the DR agent.
ISSYNCED	STRING	A text string indicating whether the database is currently being replicated. If replication has not started, or the overflow capacity has been exceeded (that is, replication has failed), the value of ISSYNCED is "false". If replication is currently in progress, the value is "true".
MODE	STRING	A text string indicating whether this particular partition is replicating data for the DR agent ("NORMAL") or not ("PAUSED"). Only one copy of each logical partition actually sends data to the DR agent during replication. So for clusters with a K-safety value greater than zero, not all physical partitions will report "NORMAL" even when replication is in progress.

The second table returns a row for every host in the cluster, showing whether a replication snapshot is in progress and if it is, the status of transmission to the DR agent.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
HOST_ID	INTEGER	Numeric ID for the host node.
HOSTNAME	STRING	Server name of the host node.
ENABLED	STRING	A text string indicating whether the database is currently being replicated. Possible values are "true" and "false".
SYNCSNAPSHOTSTATE	STRING	A text string indicating the current state of the synchronization snapshot that begins replication. During normal operation, this value is "NOT_SYNCING" indicating either that replication is not active or that transactions are actively being replicated. If a synchronization snapshot is in progress, this value provides additional infomation about the specific activity underway.
ROWSINSYNCSNAPSHOT	BIGINT	Reserved for future use.
ROWSACKEDFORSYNCSNAPSHOT	BIGINT	Reserved for future use.

INDEX — Returns a row for every index in every execution site.

Name

Datatype

Description

TIMESTAMP

BIGINT

The timestamp when the information was collected (in milliseconds).

HOST_ID

BIGINT

Numeric ID for the host node.

HOSTNAME

STRING

Server name of the host node.

SITE_ID

BIGINT

Numeric ID of the execution site on the host node.

PARTITION_ID

BIGINT

The numeric ID for the logical partition that this site represents. When using a K value greater than zero, there are multiple copies of each logical partition.

INDEX_NAME

STRING

The name of the index.

TABLE_NAME

STRING

The name of the database table to which the index applies.

INDEX_TYPE

STRING

A text string identifying the type of the index as either a hash or tree index and whether it is unique or not. Possible values include the followiing:

CompactingHashMultiMapIndex

CompactingHashUniqueIndex

CompactingTreeMultiMapIndex

CompactingTreeUniqueIndex

IS_UNIQUE

TINYINT

A byte value specifying whether the index is unique (1) or not (0).

IS_COUNTABLE

TINYINT

A byte value specifying whether the index maintains a counter to optimize COUNT(*) queries.

ENTRY_COUNT

BIGINT

The number of index entries currently in the partition.

MEMORY_ESTIMATE

INTEGER

The estimated amount of memory (in kilobytes) consumed by the current index entries.

INITIATOR — Returns a separate row for each connection and the stored procedures initiated by that connection.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
HOST_ID	INTEGER	Numeric ID for the host node.
HOSTNAME	STRING	Server name of the host node.
SITE_ID	INTEGER	Numeric ID of the execution site on the host node.
CONNECTION_ID	BIGINT	Numeric ID of the client connection invoking the procedure.
CONNECTION_HOSTNAME	STRING	The server name of the node from which the client connection originates.
PROCEDURE_NAME	STRING	The name of the stored procedure.
INVOCATIONS	BIGINT	The number of times the stored procedure has been invoked by this connection on this host node.
AVG_EXECUTION_TIME	INTEGER	The average length of time (in milliseconds) it took to execute the stored procedure.
MIN_EXECUTION_TIME	INTEGER	The minimum length of time (in milliseconds) it took to execute the stored procedure.
MAX_EXECUTION_TIME	INTEGER	The maximum length of time (in milliseconds) it took to execute the stored procedure.
ABORTS	BIGINT	The number of times the procedure was aborted.
FAILURES	BIGINT	The number of times the procedure failed unexpectedly. (As opposed to user aborts or expected errors, such as constraint violations.)

IOSTATS — Returns one row for every client connection on the cluster.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
HOST_ID	INTEGER	Numeric ID for the host node.
HOSTNAME	STRING	Server name of the host node.
CONNECTION_ID	BIGINT	Numeric ID of the client connection invoking the procedure.
CONNECTION_HOSTNAME	STRING	The server name of the node from which the client connection originates.
BYTES_READ	BIGINT	The number of bytes of data sent from the client to the host.
MESSAGES_READ	BIGINT	The number of individual messages sent from the client to the host.
BYTES_WRITTEN	BIGINT	The number of bytes of data sent from the host to the client.
MESSAGES_WRITTEN	BIGINT	The number of individual messages sent from the host to the client.

LIVECLIENTS — Returns a row for every client connection currently active on the cluster.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
HOST_ID	INTEGER	Numeric ID for the host node.
HOSTNAME	STRING	Server name of the host node.
CONNECTION_ID	BIGINT	Numeric ID of the client connection invoking the procedure.
CLIENT_HOSTNAME	STRING	The server name of the node from which the client connection originates.
ADMIN	TINYINT	A byte value specifying whether the connection is to the client port (0) or the admin port (1).
OUTSTANDING_REQUEST_BYTES	BIGINT	The number of bytes of data sent from the client currently pending on the host.
OUTSTANDING_RESPONSE_MESSAGES	BIGINT	The number of messages on the host queue waiting to be retrieved by the client.
OUTSTANDING_ TRANSACTIONS	BIGINT	The number of transactions (that is, stored procedures) initiated on behalf of the client that have yet to be completed.

MEMORY — Returns a row for every server in the cluster.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
HOST_ID	INTEGER	Numeric ID for the host node.
HOSTNAME	STRING	Server name of the host node.
RSS	INTEGER	The current resident set size. That is, the total amount of memory allocated to the VoltDB processes on the server.
JAVAUSED	INTEGER	The amount of memory (in kilobytes) allocated by Java and currently in use by VoltDB.
JAVAUNUSED	INTEGER	The amount of memory (in kilobytes) allocated by Java but unused. (In other words, free space in the Java heap.)
TUPLEDATA	INTEGER	The amount of memory (in kilobytes) currently in use for storing database records.
TUPLEALLOCATED	INTEGER	The amount of memory (in kilobytes) allocated for the storage of database records (including free space).
INDEXMEMORY	INTEGER	The amount of memory (in kilobytes) currently in use for storing database indexes.
STRINGMEMORY	INTEGER	The amount of memory (in kilobytes) currently in use for storing string and binary data that is not stored "in-line" in the database record.
TUPLECOUNT	BIGINT	The total number of database records currently in memory.
POOLEDMEMORY	BIGINT	The total size of memory (in kilobytes) allocated for tasks other than database records, indexes, and strings. (For example, pooled memory is used for temporary tables while processing stored procedures.)
PHYSICALMEMORY	BIGINT	The total size of physical memory (in kilobytes) on the server.

PARTITIONCOUNT — Returns one row identifying the total number of partitions and the host that provided that information.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
HOST_ID	INTEGER	Numeric ID for the host node.
HOSTNAME	STRING	Server name of the host node.
PARTITION_COUNT	INTEGER	The number of unique or logical partitions on the cluster. When using a K value greater than zero, there are multiple copies of each logical partition.

PLANNER — Returns a row for every planner cache. That is, one cache per execution site, plus one global cache per server. (The global cache is identified by a site and partition ID of minus one.)

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
HOST_ID	INTEGER	Numeric ID for the host node.
HOSTNAME	STRING	Server name of the host node.
SITE_ID	INTEGER	Numeric ID of the execution site on the host node.
PARTITION_ID	INTEGER	The numeric ID for the logical partition that this site represents. When using a K value greater than zero, there are multiple copies of each logical partition.
CACHE1_LEVEL	INTEGER	The number of query plans in the level 1 cache.
CACHE2_LEVEL	INTEGER	The number of query plans in the level 2 cache.
CACHE1_HITS	INTEGER	The number of queries that matched and reused a plan in the level 1 cache.
CACHE2_HITS	INTEGER	The number of queries that matched and reused a plan in the level 2 cache.
CACHE_MISSES	INTEGER	The number of queries that had no match in the cache and had to be planned from scratch
PLAN_TIME_MIN	BIGINT	The minimum length of time (in nanoseconds) it took to complete the planning of ad hoc queries.
PLAN_TIME_MAX	BIGINT	The maximum length of time (in nanoseconds) it took to complete the planning of ad hoc queries.
PLAN_TIME_AVG	BIGINT	The average length of time (in nanoseconds) it took to complete the planning of ad hoc queries.
FAILURES	BIGINT	The number of times planning for an ad hoc query failed.

PROCEDURE — Returns a row for every stored procedure that has been executed on the cluster, grouped by execution site.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
HOST_ID	INTEGER	Numeric ID for the host node.
HOSTNAME	STRING	Server name of the host node.
SITE_ID	INTEGER	Numeric ID of the execution site on the host node.
PARTITION_ID	INTEGER	The numeric ID for the logical partition that this site represents. When using a K value greater than zero, there are multiple copies of each logical partition.
PROCEDURE	STRING	The class name of the stored procedure.
INVOCATIONS	BIGINT	The total number of invocations of this procedure at this site.
TIMED_INVOCATIONS	BIGINT	The number of invocations used to measure the minimum, maximum, and average execution time.
MIN_EXECUTION_TIME	BIGINT	The minimum length of time (in nanoseconds) it took to execute the stored procedure.
MAX_EXECUTION_TIME	BIGINT	The maximum length of time (in nanoseconds) it took to execute the stored procedure.
AVG_EXECUTION_TIME	BIGINT	The average length of time (in nanoseconds) it took to execute the stored procedure.
MIN_RESULT_SIZE	INTEGER	The minimum size (in bytes) of the results returned by the procedure.
MAX_RESULT_SIZE	INTEGER	The maximum size (in bytes) of the results returned by the procedure.
AVG_RESULT_SIZE	INTEGER	The average size (in bytes) of the results returned by the procedure.
MIN_PARAMETER_SET_SIZE	INTEGER	The minimum size (in bytes) of the parameters passed as input to the procedure.
MAX_PARAMETER_SET_SIZE	INTEGER	The maximum size (in bytes) of the parameters passed as input to the procedure.
AVG_PARAMETER_SET_SIZE	INTEGER	The average size (in bytes) of the parameters passed as input to the procedure.
ABORTS	BIGINT	The number of times the procedure was aborted.
FAILURES	BIGINT	The number of times the procedure failed unexpectedly. (As opposed to user aborts or expected errors, such as constraint violations.)

PROCEDUREINPUT — Returns a row for every stored procedure that has been executed on the cluster, summarized across the cluster.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
PROCEDURE	STRING	The class name of the stored procedure.
WEIGHTED_PERC	BIGINT	A weighted average expressed as a percentage of the parameter set size for invocations of this stored procedure compared to all stored procedure invocations.
INVOCATIONS	BIGINT	The total number of invocations of this procedure.
MIN_PARAMETER_SET_SIZE	BIGINT	The minimum parameter set size in bytes.
MAX_PARAMETER_SET_SIZE	BIGINT	The maximum parameter set size in bytes.
AVG_PARAMETER_SET_SIZE	BIGINT	The average parameter set size in bytes.
TOTAL_PARAMETER_SET_SIZE_MB	BIGINT	The total input for all invocations of this stored procedure measured in megabytes.

PROCEDUREOUTPUT — Returns a row for every stored procedure that has been executed on the cluster, summarized across the cluster.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
PROCEDURE	STRING	The class name of the stored procedure.
WEIGHTED_PERC	BIGINT	A weighted average expressed as a percentage of the result set size returned by invocations of this stored procedure compared to all stored procedure invocations.
INVOCATIONS	BIGINT	The total number of invocations of this procedure.
MIN_RESULT_SIZE	BIGINT	The minimum result set size in bytes.
MAX_RESULT_SIZE	BIGINT	The maximum result set size in bytes.
AVG_RESULT_SIZE	BIGINT	The average result set size in bytes.
TOTAL_RESULT_SIZE_MB	BIGINT	The total output returned by all invocations of this stored procedure measured in megabytes.

PROCEDUREPROFILE — Returns a row for every stored procedure that has been executed on the cluster, summarized across the cluster.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
PROCEDURE	STRING	The class name of the stored procedure.
WEIGHTED_PERC	BIGINT	A weighted average expressed as a percentage of the execution time for this stored procedure compared to all stored procedure invocations.
INVOCATIONS	BIGINT	The total number of invocations of this procedure.
AVG	BIGINT	The average length of time (in nanoseconds) it took to execute the stored procedure.
MIN	BIGINT	The minimum length of time (in nanoseconds) it took to execute the stored procedure.
MAX	BIGINT	The maximum length of time (in nanoseconds) it took to execute the stored procedure.
ABORTS	BIGINT	The number of times the procedure was aborted.
FAILURES	BIGINT	The number of times the procedure failed unexpectedly. (As opposed to user aborts or expected errors, such as constraint violations.)

REBALANCE — Returns one row if the cluster is rebalancing. No data is returned if the cluster is not rebalancing.

Warning

The rebalance selector is still under development. The return values are likely to change in upcoming releases.

Name	Datatype	Description
TOTAL_RANGES	BIGINT	The total number of partition segments to be migrated.
PERCENTAGE_MOVED	FLOAT	The percentage of the total segments that have already been moved.
MOVED_ROWS	BIGINT	The number of rows of data that have been moved.
ROWS_PER_SECOND	FLOAT	The average number of rows moved per second.
ESTIMATED_REMAINING	BIGINT	The estimated time remaining until the rebalance is complete, in milliseconds.
MEGABYTES_PER_SECOND	FLOAT	The average volume of data moved per second, measured in megabytes.
CALLS_PER_SECOND	FLOAT	The average number of rebalance work units, or transactions, executed per second.
CALLS_LATENCY	FLOAT	The average execution time for rebalance transactions, in milliseconds.

SNAPSHOTSTATUS — Returns a row for every snapshot file in the recent snapshots performed on the cluster.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the snapshot was initiated (in milliseconds).
HOST_ID	INTEGER	Numeric ID for the host node.
HOSTNAME	STRING	Server name of the host node.
TABLE	STRING	The name of the database table whose data the file contains.
PATH	STRING	The directory path where the snapshot file resides.
FILENAME	STRING	The file name.
NONCE	STRING	The unique identifier for the snapshot.
TXNID	BIGINT	The transaction ID of the snapshot.
START_TIME	BIGINT	The timestamp when the snapshot began (in milliseconds).
END_TIME	BIGINT	The timestamp when the snapshot was completed (in milliseconds).
SIZE	BIGINT	The total size, in bytes, of the file.
DURATION	BIGINT	The length of time (in milliseconds) it took to complete the snapshot.
THROUGHPUT	FLOAT	The average number of bytes per second written to the file during the snapshot process.
RESULT	STRING	String value indicating whether the writing of the snapshot file was successful ("SUCCESS") or not ("FAILURE").

TABLE — Returns a row for every table, per partition. In other words, the number of tables, multiplied by the number of sites per host and the number of hosts.

Name	Datatype	Description
TIMESTAMP	BIGINT	The timestamp when the information was collected (in milliseconds).
HOST_ID	BIGINT	Numeric ID for the host node.
HOSTNAME	STRING	Server name of the host node.
SITE_ID	BIGINT	Numeric ID of the execution site on the host node.
PARTITION_ID	BIGINT	The numeric ID for the logical partition that this site represents. When using a K value greater than zero, there are multiple copies of each logical partition.
TABLE_NAME	STRING	The name of the database table.
TABLE_TYPE	STRING	The type of the table. Values returned include "PersistentTable" for normal data tables and views and "StreamedTable" for export-only tables.
TUPLE_COUNT	BIGINT	The number of rows currently stored for this table in the current partition. For export-only tables, the cumulative total number of rows inserted into the table.
TUPLE_ALLOCATED_MEMORY	INTEGER	The total size of memory, in kilobytes, allocated for storing inline data associated with this table in this partition. The allocated memory can exceed the currently used memory (TUPLE_DATA_MEMORY). For export-only tables, this field identifies the amount of memory currently in use to queue export data (both in memory and as export overflow) prior to its being passed to the export target.
TUPLE_DATA_MEMORY	INTEGER	The total memory, in kilobytes, used for storing inline data associated with this table in this partition. The total memory used for storing data for this table is the combination of memory used for inline (tuple) and non-inline (string) data.
STRING_DATA_MEMORY	INTEGER	The total memory, in kilobytes, used for storing non-inline variable length data (VARCHAR and VARBINARY) associated with this table in this partition. The total memory used for storing data for this table is the combination of memory used for inline (tuple) and non-inline (string) data.
TUPLE_LIMIT	INTEGER	The row limit for this table. Row limits are optional and are defined in the schema as a maximum number of rows that any partition can contain. If no row limit is set, this value is null.
PERCENT_FULL	INTEGER	The percentage of the row limit currently in use by table rows in this partition. If no row limit is set, this value is zero.

Examples

The following example uses @Statistics to gather information about the distribution of table rows within the cluster:

$ sqlcmd
1> exec @Statistics TABLE, 0;

The next program example shows a procedure that collects and displays the number of transactions (i.e. stored procedures) during a given interval, by setting the delta-flag to a non-zero value. By calling this procedure iteratively (for example, every five minutes), it is possible to identify fluctuations in the database workload over time (as measured by the number of transactions processed).

void measureWorkload() {
  VoltTable[] results = null;
  String procName;
  int procCount = 0;
  int sysprocCount = 0;

  try { results = client.callProcedure("@Statistics",
                  "INITIATOR",1).getResults(); }
  catch (Exception e) { e.printStackTrace(); }

  for (VoltTable t: results) { 
     for (int r=0;r<t.getRowCount();r++) {
         VoltTableRow row = t.fetchRow(r);
         procName = row.getString("PROCEDURE_NAME");
                /* Count system procedures separately */
         if (procName.substring(0,1).compareTo("@") == 0)
           { sysprocCount += row.getLong("INVOCATIONS"); }
         else 
           { procCount += row.getLong("INVOCATIONS"); }
     }
  }
  System.out.printf("System procedures: %d\n" +
                    "User-defined procedures: %d\n",+
                    sysprocCount,procCount);
}

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