HOPEX Administration > Administrator Guide > Managing Repositories > Optimizing Repository Access Performance > Managing cache in RDBMS environments
Managing cache in RDBMS environments
The RDBMS local cache avoid multiple requests when multiple users are on the same repository view. Access for the following users is speed up.
By default the RDBMS local cache is activated on SystemDb repository only:
• You must configure your anti-virus accordingly.
• You can:
• increase RDBMS cache size (memory).
• extend the RDBMS local cache option to all the repositories or disable the option.
RDBMS local cache files are generated in .mgc format. They are stored in RDBMS Data sub-folder accessible from: <ProgramData>\MEGA\HOPEX <HOPEX version>\Cache\ folder.
*To modify the HOPEX cache location, see Modifying HOPEX cache location.
Increasing RDBMS cache size (memory)
In RDBMS storage case, with repositories including a large amount of objects, we advise you to increase the size of RDBMS caches. The larger your cache space, the fewer the network exchanges and the better your HOPEX performance.
To increase cache size:
1. Connect to HOPEX Administration and select the environment in which the repository is referenced.
2. Right-click the environment and select Options > Modify.
3. In the environment options, select Options > Installation > Advanced.
4. Increase cache sizes depending on your memory space.
Modifying HOPEX cache location 
By default, HOPEX caches are stored in <ProgramData>\MEGA\HOPEX <HOPEX version>\Cache\ directory sub-folders:
• Compiled data
• Pictures
• RDBMS data
If needed you can change HOPEX cache folder location.
To modify the HOPEX cache folder location:
1. Connect to HOPEX Administration.
2. Right-click the Site (HOPEX) and select Options > Modify.
3. In the environment options, select Options > Installation > Advanced.
4. In Path of HOPEX cache field, enter a location.
This location indicates the location where HOPEX must read and write its cache data.
*For this location select a local drive that has a good access time.
Extending or disabling RDBMS local cache files 
By default RDBMS local cache is enabled on SystemDb repository only. According to your infrastructure performances, you can extend the storage to the other repositories or disabled the storage.
*You must be an advanced user to modify this option.
Modifying the scope of the RDBMS local cache files depends on:
• the latency between HOPEX application server and RDBMS databases, and
• Reading/Writing performances of HOPEX application server local disks.
Local disk performance (reading/writing)
Low latency
(< 2 ms)
2 ms < Latency < 5 ms
High latency
(5 ms <)
Good
(SSD, physical infrastructure)
SytemDb only
SytemDb only
All repositories
Fair
(virtual infrastructure)
Disabled
SytemDb only
SytemDb only
To modify the default scope of RDBMS local cache files:
1. Connect to HOPEX Administration.
2. Right-click the Site (HOPEX) and select Options > Modify.
3. In the environment options, select Options > Installation > Advanced.
4. Modify the Scope of HOPEX-RDBMS local cache option value according to your infrastructure performances.
*Default value: “SytemDb only”.
Cyphering RDBMS local cache data 
Cyphering of RDBMS local cache option enables cyphering data included in the RDBMS local cache. Selecting this option decreases the benefit of RDBMS local cache activation. In that case, balance the benefit of storing the RDBMS local cache files with Scope of HOPEX-RDBMS local cache option activation.
To cypher the data of the RDBMS local cache files:
1. Connect to HOPEX Administration.
2. Right-click the Site (HOPEX) and select Options > Modify.
3. In the environment options, select Options > Installation > Advanced.
4. Select Cyphering of HOPEX-RDBMS cache option.