topic Re: Buffering ????? in Application Development and Automation Discussions

topic Re: Buffering ????? in Application Development and Automation Discussions https://community.sap.com/t5/application-development-and-automation-discussions/buffering/m-p/1789837#M339865 <HTML><HEAD></HEAD><BODY><P>instead of hitting the database table again & again we used to buffer the data.</P><P>to reduce the network we go to buffering.</P><P></P><P>while creating table itself we will specify whether the table to be buffered or not.</P><P>If buffered we have to specify the type .See the technical setting in table.</P><P></P><P>if u want the updated data from the table means we have to use </P><P>select query with bypass buffer option.</P></BODY></HTML> Wed, 20 Dec 2006 06:16:38 GMT Former Member 2006-12-20T06:16:38Z Buffering ????? https://community.sap.com/t5/application-development-and-automation-discussions/buffering/m-p/1789835#M339863 <HTML><HEAD></HEAD><BODY><P>Hi Experts,</P><P> could anyone explain me what is buffering in data dictionary? what is the use of it?</P><P></P><P></P><P></P><P>Thanks in advance,</P><P>Ramana</P></BODY></HTML> Wed, 20 Dec 2006 06:12:05 GMT https://community.sap.com/t5/application-development-and-automation-discussions/buffering/m-p/1789835#M339863 Former Member 2006-12-20T06:12:05Z Re: Buffering ????? https://community.sap.com/t5/application-development-and-automation-discussions/buffering/m-p/1789836#M339864 <HTML><HEAD></HEAD><BODY><P>check sap help.</P><P><A href="http://help.sap.com/saphelp_47x200/helpdata/en/c4/3a6de2505211d189550000e829fbbd/frameset.htm" target="test_blank">http://help.sap.com/saphelp_47x200/helpdata/en/c4/3a6de2505211d189550000e829fbbd/frameset.htm</A></P></BODY></HTML> Wed, 20 Dec 2006 06:14:05 GMT https://community.sap.com/t5/application-development-and-automation-discussions/buffering/m-p/1789836#M339864 Former Member 2006-12-20T06:14:05Z Re: Buffering ????? https://community.sap.com/t5/application-development-and-automation-discussions/buffering/m-p/1789837#M339865 <HTML><HEAD></HEAD><BODY><P>instead of hitting the database table again & again we used to buffer the data.</P><P>to reduce the network we go to buffering.</P><P></P><P>while creating table itself we will specify whether the table to be buffered or not.</P><P>If buffered we have to specify the type .See the technical setting in table.</P><P></P><P>if u want the updated data from the table means we have to use </P><P>select query with bypass buffer option.</P></BODY></HTML> Wed, 20 Dec 2006 06:16:38 GMT https://community.sap.com/t5/application-development-and-automation-discussions/buffering/m-p/1789837#M339865 Former Member 2006-12-20T06:16:38Z Re: Buffering ????? https://community.sap.com/t5/application-development-and-automation-discussions/buffering/m-p/1789838#M339866 <HTML><HEAD></HEAD><BODY><P>HI</P><P></P><P>Buffering means of keeping the table data in the buffer of the application server after the first access.</P><P></P><P>Buffering allows you to read the data from main memory next time it is accessed, thus saving a further database access.</P><P></P><P>The buffering type is defined in the technical settings for a table.</P><P>There are three types of buffering:</P><P>Full buffering: All the records of the table are loaded into the buffer when one record of the table is accessed. </P><P></P><P>Generic buffering: When a record of the table is accessed, all the records having this record in the generic key fields (part of the table key that is left-justified, identified by specifying a number of key fields) are loaded into the buffer. </P><P></P><P>Single-record buffering: Only the records of a table that are really accessed are loaded into the buffer.</P><P></P><P>Just have a look at these links:</P><P></P><P><A class="jive_macro jive_macro_thread" href="https://community.sap.com/" __jive_macro_name="thread" modifiedtitle="true" __default_attr="274144"></A></P><P></P><P>Regards,</P><P>Gunasree.</P></BODY></HTML> Wed, 20 Dec 2006 06:24:47 GMT https://community.sap.com/t5/application-development-and-automation-discussions/buffering/m-p/1789838#M339866 Former Member 2006-12-20T06:24:47Z Re: Buffering ????? https://community.sap.com/t5/application-development-and-automation-discussions/buffering/m-p/1789839#M339867 <HTML><HEAD></HEAD><BODY><P>Hi,</P><P></P><P>Whenever an Open SQL statement is used to read a record, the data buffer is checked first to see whether it is there. If not, the data is read from the database. If the table's attributes indicate that the data should be buffered, the record is saved in RAM on the application server in data buffers. Later, if that record is read again, it is read from the buffer instead of the database.</P><P></P><P>By buffering data, you increase performance in two important ways: </P><P></P><P>The programs using the buffered data run faster because they don't have to wait for it to come from the database. This reduces delays waiting for the database and the network that connects it. </P><P></P><P>The other programs that need to access the database run faster because there is less load on the database and less traffic on the network. </P><P></P><P>Three types of buffering are possible: </P><P></P><P>Full buffering </P><P>Generic buffering </P><P>Single-record buffering </P><P>Although you use a check box to indicate the buffering type, only one type can be selected at a time. If you choose more than one, an error message will be displayed. </P><P></P><P>There are two data buffers on each application server, and the buffering type chosen determines which buffer is used. On an application sever there are: </P><P></P><P>The generic record buffer </P><P>The single-record buffer </P><P>The generic record buffer is called TABL (short for "table"). The single-record buffer is TABLP ("P"' stands for "partial"). </P><P></P><P>Full Buffering:</P><P>To activate the full buffering type, tickmark the Full check box. When an attempt is made to read data from a fully buffered table, the system looks in the TABL buffer for it. If it is not found there, all rows are loaded from the database into TABL . This happens whenever a select statement for it is executed, no matter how many records match the where clause. Even if no records match, all are loaded into the buffer if the table is not already there or if it has been invalidated due to buffer synchronization. </P><P></P><P>Loading of TABL does not occur with select single statements; only select/ endselect does this. If the table is fully buffered and a select single statement is executed, no records are loaded into TABL. However, if the table is already loaded into TABL, select single will read records from it. </P><P>During buffer synchronization, the entire table is invalidated if any record within it changes. The next time data is read the entire table is reloaded.</P><P></P><P>Full buffering is appropriate for small tables that seldom change.</P><P></P><P>Generic Buffering:</P><P>With generic buffering, a group of records is loaded into TABL instead of the entire table. To activate this type of buffering, tickmark the Generic check box and put a number n in the No. of Key Fields so that the n left-most fields of the primary key will group records. When a record is read and n is 1, all records having the same value in the first field of the primary key are loaded into the buffer. When a record is read and n is 2, all records having the same value in the first two fields of the primary key are loaded into the buffer. </P><P></P><P>Generic buffering is suitable for tables in which records are usually accessed in sets or groups. </P><P></P><P>Single Record Buffering:</P><P>With this type of buffering, select single picks one record into the single record buffer TABLP. With this buffering type, records are only buffered when the select single statement is executed. Select/endselect does not load or read TABLP. </P><P>Single-record buffering is appropriate for very large tables in which a small percentage of the records are read often. For single-record buffering to work, records must be read using the select single statement. </P><P></P><P></P><P>There are two buffers: TABL (the generic record buffer) and TABLP (the single record buffer). There are also two varieties of the select statement: select and select single. The select statement loads TABL and the select single statement loads TABLP. </P><P>When reading, select only reads TABL; it ignores TABLP. select single reads both buffers. This behavior is summarized in Figure 5.20. Remember that a record can only be in one buffer at a time because a table can only have one buffering type. </P><P></P><P>I hope it helps.</P><P></P><P></P><P>Regards</P><P>Anver</P></BODY></HTML> Wed, 20 Dec 2006 06:27:14 GMT https://community.sap.com/t5/application-development-and-automation-discussions/buffering/m-p/1789839#M339867 anversha_s 2006-12-20T06:27:14Z