I. Introduction of row migration and row link in actual work we often encounter some problems with low Oracle database performance. Of course, there are many reasons that cause low Oracle database performance, we can use some correct design and
Scenario: If varchar and VarChar2 are modified more often, and the modified data length is different each time, this can cause a "row migration" phenomenonConcept:Row chaining and row migration (row migration)When a row of data is too long to be
Row migrations and row links lead to degraded Oracle performance, this article describes what row migration and row links are, what they do, how to judge them, and provides solutions to them.What is row migration and row link row migrationOracle's
Row height refers to the distance between the baseline of a line of text, but the spacing between the text is not just the row height, but also the font size.7.3 Line-heightRow height refers to the distance between the baseline of a line of text,
Because of the row link can only increase db_block_size to clear, and db_block_size after the creation of the database can not be changed, so there is no more than the purge of the row link, mainly for the row migration to talk about in the actual
What is a row migration row link? # The following description is from Oracle11gR2Document1. The row link Therowistoolargetofitintoonedatablockwhenitisfirstinserted. Inrowchaining, OracleDatabasestor
What is a row migration row link? # The following
Oracle Lock table row-level lock table-level lock ----row is locked exclusively ----Other users cannot modify this line until a row's lock is released----use the commit or the rollback command to release the lock ----Oracle by using INSERT, UPDATE,
Through the previous introduction we know that the main line link is due to the db_block_size of the database is not large enough for some large fields can not be stored in a block, resulting in a row link. For row links We have nothing to avoid
SQL row-to-column and column-to-row code details, SQL-to-row
Switching between rows and columns is a common requirement. Implementation methods include the case when method and the built-in unlock and ununlock methods after 2005.After reading the
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