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Are Paradox 7 files loaded into RAM at app. start?

Hey.
Dose anyone know how Delphi app. runs data from .db files (Paradox 7/Delphi 7).

Dose it?, load the table file (.db file) in RAM.
Or dose it?, read it from the HD when needed.

What I am looking for - is:
If I have a XXXLarge table (.db) file. Will the hole file be read in to RAM (then I need more RAM :?) )

My good faith tell's me that it load the Index/Primery keys in RAM and when needed gets data from HD.

Related question: If i use TQuery with different tables(.db) during the program (not at the same time) will all the tables be loaded into (RAM? related to the first question) at app. load.

I am having problems with finding the info I need. I have tryed google.

Sorry my difficult setup of the question and my english. Hope somebody can help.
BG. Asbjrn

Comments

  • zibadianzibadian Member Posts: 6,349
    : Hey.
    : Dose anyone know how Delphi app. runs data from .db files (Paradox 7/Delphi 7).
    :
    : Dose it?, load the table file (.db file) in RAM.
    : Or dose it?, read it from the HD when needed.
    :
    : What I am looking for - is:
    : If I have a XXXLarge table (.db) file. Will the hole file be read in to RAM (then I need more RAM :?) )
    :
    : My good faith tell's me that it load the Index/Primery keys in RAM and when needed gets data from HD.
    :
    : Related question: If i use TQuery with different tables(.db) during the program (not at the same time) will all the tables be loaded into (RAM? related to the first question) at app. load.
    :
    : I am having problems with finding the info I need. I have tryed google.
    :
    : Sorry my difficult setup of the question and my english. Hope somebody can help.
    : BG. Asbjrn
    :
    This depends on the setup of the database access. Most databases load only the indexes and a few records into the RAM and update those as the user navigates the database. If the database is small enough it will most probably load entirely into the RAM, but really large databases (a few gigs or more) will most certainly be loaded partially. This again depending on the available RAM and precise options of the database.
    In case of sql queries, it will behave in the same way: only loading the necessary records for really large databases.

    I hope this answers your questions. Normally you don't have to worry about this kind of things, since the DBE will take care of the precise inner workings of the database, and determine if it can load the entire database or not.
  • neoandresenneoandresen Member Posts: 7
    : : Hey.
    : : Dose anyone know how Delphi app. runs data from .db files (Paradox 7/Delphi 7).
    : :
    : : Dose it?, load the table file (.db file) in RAM.
    : : Or dose it?, read it from the HD when needed.
    : :
    : : What I am looking for - is:
    : : If I have a XXXLarge table (.db) file. Will the hole file be read in to RAM (then I need more RAM :?) )
    : :
    : : My good faith tell's me that it load the Index/Primery keys in RAM and when needed gets data from HD.
    : :
    : : Related question: If i use TQuery with different tables(.db) during the program (not at the same time) will all the tables be loaded into (RAM? related to the first question) at app. load.
    : :
    : : I am having problems with finding the info I need. I have tryed google.
    : :
    : : Sorry my difficult setup of the question and my english. Hope somebody can help.
    : : BG. Asbjrn
    : :
    : This depends on the setup of the database access. Most databases load only the indexes and a few records into the RAM and update those as the user navigates the database. If the database is small enough it will most probably load entirely into the RAM, but really large databases (a few gigs or more) will most certainly be loaded partially. This again depending on the available RAM and precise options of the database.
    : In case of sql queries, it will behave in the same way: only loading the necessary records for really large databases.
    :
    : I hope this answers your questions. Normally you don't have to worry about this kind of things, since the DBE will take care of the precise inner workings of the database, and determine if it can load the entire database or not.
    :

    Yes I think i covered my question. Thx. You said that you don't worry about this things. I think that it is very important to know how your app. uses the computer it are being executed on. I write High performance app. With big databases. But it is some years since I have worked with Delphi. PHP & Unix/Linux programming has been my langauge for some time.
    Again THX.
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