Monitoring Database Storage in xSQL

Sometimes it is useful to see the amount of database memory space available in the database. xSQL provides the mem command for this purpose. It displays the amount of total and free storage in the database. The available storage is displayed in bytes (-b), Kilobytes (-k, default), Megabytes (-m), Gigabytes (-g), Terabytes (-t) or memory pages (-p)

 
    XSQL>mem [-b|-k|-m|-g|-t|-p]
     

For example, the following displays memory usage for an in-memory database:

 
    XSQL>mem
    Total         Used               Free
    Mem :    102212            6      	     102205
 
    XSQL>mem -b
    Total         Used               Free
    Mem : 104665344         6656       	  104658688
     

Examining Dictionary Memory Usage

In order to dynamically modify the database layout via the dynamic DDL, the database must have space for dynamically created classes and indexes preallocated (reserved ) in advance. The memddl command displays the amount of the reserved space, the already used and available sizes. For example:

 
    XSQLCMD>memddl
    Reserved             Used        Available
    Classes    :              100                1               99
    Indexes    :             1000                1              999
    Dict. size :             32Kb              0Kb             31Kb
     

Persistent Databases

The mem command displays the following persistent storage usage for a persistent database :

 
    XSQL>mem
    Total            Used            Free
    Mem :    102154              12          102141
    Disk:       128             121
            
    Log :       833