GD33-jLYBFA/UF888alJRQI/AAAAAAAAAaU/xAW6t-gLu7w/s1600/crs2.jpg' alt='Odbc Oracle 11.2' title='Odbc Oracle 11.2' />This section describes the connection URL format and how to create connection objects with the DriverManager class. I installed ODAC 11. Release 3 and Oracle Developer Tools for Visual Studio 11. Oracle Latches Database. Journal. com. Latches can be confusing. Sessions can wait for them and when those waits become excessive performance degrades. To many they appear to be the same as locks, but they arent, even though lock waits, when the times get excessive, can also degrade performance. So, what are the differences between latches and locks Lets examine both and see where they differ, what can cause latch waits and how latch waits can be investigated. Latches are similar to locks but they operate on memory to protect code and internal data structures by preventing concurrent access. For example, the LRU latches are used when managing the buffer cache, an operation that is restricted to being run by a single process other processes must wait for the current process to complete its actions on the buffer cache before the next one in line can proceed. The latch holds this structure for the current process to access when the current process is done the latch is released and the next process in the queue can acquire it. Since only one process at a time can hold a latch, popular actions can create a long line of processes waiting to obtain the associated latch. Normally latch waits are in milliseconds or fractions of milliseconds so waiting for a latch usually isnt noticeable. Lets look at the differences between a lock and a latch Locks. Protect the logical contents of the database object table, index from other transactions. Are held for the transaction duration. Provide rollback capability for the associated transaction. Protect the critical sections of the associated internal data structures from other threads. Are held only until the operation completes and then are released. Prevent concurrent access to a memory structure. Run-Setup.exe1.png' alt='Odbc Oracle 11.2' title='Odbc Oracle 11.2' />Oracles Instant Client ODBC software is a standalone package that offers the full functionality of the Oracle ODBC driver except the Oracle service for Microsoft. Note Oracle ODBC Driver is supported only for the Linux x86, Linux Itanium, and Solaris SPARC 64 platforms. What is the Oracle ODBC Driver. The Oracle ODBC Driver enables ODBC applications on Microsoft Windows, as well as UNIX platforms like Linux, Solaris, and IBM. With a new Oracle Installation when I go to Configuration Management Tools Microsoft ODBC Administrator System DSN Add new installation it does not. L.jpg' alt='Odbc Oracle 11.2' title='Odbc Oracle 11.2' />Since memory operations arent transactions the ability to rollback a change isnt necessary clearing a buffer so another process can use it is a fast, irreversible operation that isnt designed to be undone. Contrast that to a lock, which controls access to change data in a table such actions are transactional in nature and are designed with the ability to undo the changes should the need arise. Locks can also protect a data image while its being read, which gives rise to the different types of locks that are available shared, row shared, row shared exclusive, exclusive that govern who and how the data can be modified. Oracle latches are interesting items that can protect, and sometimes hinder, object access. Read on to see what they are, how they work and how they can sometimes. SSIS. Oracle ODBC Instantclient 11g Install. County Ad Hoc Query Users. Reference Document 143. January 17, 2012. Setting up an Oracle ODBC Driver and Data Source requires more steps than the Microsoft SQL Server database setup. This article explains the steps including. You must accept the Oracle Technology Network License Agreement to download this software. Subject to the Oracle Technology Network License Agreement for Oracle. Without exception, every lock in an Oracle database allows other sessions to read data in the locked table the locks are there to control concurrent updates and protect against the possibility of lost transactions. Latches can indicate the existence of a locking problem, as the cursor pins wait on x latch illustrates. This latch, when its wait times become long, usually indicates an issue with a hot block, a data or index block that is so popular everyone and their Aunt Gertrude are waiting for it. Long waits for this latch usually accompany concurrent sessions inserting data into a table using a sequence the sequence values will be clustered together and will usually access the same data for direct path inserts or index block and can cause sessions to wait until the current process completes. And since the latch allows one, and only one, process access to it at a time the rest of the interested transactions and their processes form a long queue, sort of like a really busy day at the amusement park. In such cases addressing the locking problem also addresses the latching problem. Various tools are available to investigate latching issues Tanel Poder has written two scripts, latchprof. They can be invaluable in investigating latch waits and contention. An example of the output that can be generated is shown below. Latch. Prof. X 2. Tanel Poder http www. SID NAME HMODE FUNC OBJECT SQLID Held Gets Held Held ms Avg hold ms. DML lock allocation exclusive ktadmc 0 9brz. D8. 25 8n. 2dsqpu. KTILM latch shared ktilmht get 0 bnqcqzztx. KTILM latch shared ktilmht get 0 8n. B 9zg. 9qd. 9bm. 4spu 2. B 9zg. 9qd. 9bm. 4spu 1. KTILM latch shared ktilmht get 0 gt. KTILM latch shared ktilmht get 0 by. KTILM latch shared ktilmht get 0 4twyxstjxggc. C 9brz. 3jsxmf. 4ts 9 1. KTILM latch shared ktilmht get 0 2. A 2. 4kkd. 5u. 3fdf. C1 5wwkp. 7spyq. 2fn 8 1. EditionRNs/ToadForOracle/Images/NITR/11.0_CA_ReportTab_NITR.png' alt='Odbc Oracle 11.2' title='Odbc Oracle 11.2' />In this example the latchprofx. SID of the holding session, the name of the latch, the mode in which the latch is held notice that almost all of the latches reported are exclusive, the associated kernel function, the object involved for latches associated with transactional activity, the number of times the latch has been held, the number of times the latch has been gotten successfully, the percentage of gets to holds, the total hold time in milliseconds and the average hold time, again in milliseconds. The report is ordered by the HELD values to make it easier to see which latches are being held and for how long. Other values can be output depending upon the parameters passed to the script. As latches control access to memory structures anything that affects how memory is allocated and used can affect them. Its possible to run afoul of latch contention when memory leaks occur usually caused by code that doesnt properly manage the memory structures it uses. Common memory leaks involve memory areas that are no longer used but are no longer accessible because the code that created the memory structure didnt free it properly. As available memory slowly decreases from these leaks it can become more difficult to obtain a latch, resulting in queues that are much longer than they would normally be. Another problem that can create the same situation is remote user sessions that die at the client but cant clean up properly, leaving orphan processes holding latches that cant be released. How such situations are managed is dependent upon the specific conditions surrounding them and resolution in extreme cases could require drastic action. Since these are usually rare occurrences these wont be discussed further. AWR and ASH reports are a good place to start when investigating wait activity and knowing whether the waits are lock or latch related of course, those reports require the Diagnostic and Tuning pack license and may not be available if your site isnt licensed. Statspack reports are also good sources of information to start an investigation and list latch activity in a dedicated report section a part of that section is reproduced below. Latch Activity DBInst FNORGfnorg Snaps 1 2. Get Requests, Pct Get Miss and Avg SlpsMiss are statistics for. No. Wait Requests, Pct No. Wait Miss are for no wait latch get requests. Pct Misses for both should be very close to 0. Pct Avg Wait Pct. Get Get Slps Time No. Wait No. Wait. Latch Requests Miss Miss s Requests Miss. New Mechwarrior Game Release Date more. AQ Background interrupt 1 0. AQ deq hash table latch 1 0. ASM db client latch 5 0. ASM map operation hash t 1 0. Change Notification Hash 3 0. Consistent RBA 4. DML lock allocation 7. Event Group Locks 1 0. File State Object Pool P 1 0. IO Staticstics latch 1 0.