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Diffstat (limited to 'docs/programmer_reference/txn_config.html')
| -rw-r--r-- | docs/programmer_reference/txn_config.html | 74 |
1 files changed, 40 insertions, 34 deletions
diff --git a/docs/programmer_reference/txn_config.html b/docs/programmer_reference/txn_config.html index a7b3c5f1..69783439 100644 --- a/docs/programmer_reference/txn_config.html +++ b/docs/programmer_reference/txn_config.html @@ -14,7 +14,7 @@ <body> <div xmlns="" class="navheader"> <div class="libver"> - <p>Library Version 11.2.5.3</p> + <p>Library Version 12.1.6.1</p> </div> <table width="100%" summary="Navigation header"> <tr> @@ -22,9 +22,7 @@ </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="txn.html">Prev</a> </td> - <th width="60%" align="center">Chapter 19. - The Transaction Subsystem - </th> + <th width="60%" align="center">Chapter 19. The Transaction Subsystem </th> <td width="20%" align="right"> <a accesskey="n" href="txn_limits.html">Next</a></td> </tr> </table> @@ -38,33 +36,43 @@ </div> </div> </div> - <p>The application may change the number of simultaneous outstanding -transactions supported by the Berkeley DB environment by calling the -<a href="../api_reference/C/envset_tx_max.html" class="olink">DB_ENV->set_tx_max()</a> method. This will also set the size of the -underlying transaction subsystem's region. When the number of -outstanding transactions is reached, additional calls to -<a href="../api_reference/C/txnbegin.html" class="olink">DB_ENV->txn_begin()</a> will fail until some active transactions complete.</p> - <p>The application can limit how long a transaction runs or blocks on -contested resources. -The <a href="../api_reference/C/envset_timeout.html" class="olink">DB_ENV->set_timeout()</a> method specifies the length of the timeout. -This value is checked whenever deadlock detection is performed or -when the transaction is about to block on a lock that cannot be -immediately granted. -Because timeouts are only checked at these times, the accuracy of the -timeout depends on how often deadlock detection is performed or how -frequently the transaction blocks.</p> - <p>There is an additional parameter used in configuring transactions; the -<a href="../api_reference/C/envset_flags.html#envset_flags_DB_TXN_NOSYNC" class="olink">DB_TXN_NOSYNC</a>. Setting the <a href="../api_reference/C/envset_flags.html#envset_flags_DB_TXN_NOSYNC" class="olink">DB_TXN_NOSYNC</a> flag to -<a href="../api_reference/C/envset_flags.html" class="olink">DB_ENV->set_flags()</a> when opening a transaction region changes the -behavior of transactions to not write or synchronously flush the log -during transaction commit.</p> - <p>This change may significantly increase application transactional -throughput. However, it means that although transactions will continue -to exhibit the ACI (atomicity, consistency, and isolation) properties, -they will not have D (durability). Database integrity will be -maintained, but it is possible that some number of the most recently -committed transactions may be undone during recovery instead of being -redone.</p> + <p> + The application may change the number of simultaneous + outstanding transactions supported by the Berkeley DB + environment by calling the <a href="../api_reference/C/envset_tx_max.html" class="olink">DB_ENV->set_tx_max()</a> method. This will + also set the size of the underlying transaction subsystem's + region. When the number of outstanding transactions is + reached, additional calls to <a href="../api_reference/C/txnbegin.html" class="olink">DB_ENV->txn_begin()</a> will fail until some + active transactions complete. + </p> + <p> + The application can limit how long a transaction runs or + blocks on contested resources. The <a href="../api_reference/C/envset_timeout.html" class="olink">DB_ENV->set_timeout()</a> method + specifies the length of the timeout. This value is checked + whenever deadlock detection is performed or when the + transaction is about to block on a lock that cannot be + immediately granted. Because timeouts are only checked at + these times, the accuracy of the timeout depends on how often + deadlock detection is performed or how frequently the + transaction blocks. + </p> + <p> + There is an additional parameter used in configuring + transactions; the <a href="../api_reference/C/envset_flags.html#envset_flags_DB_TXN_NOSYNC" class="olink">DB_TXN_NOSYNC</a>. Setting the <a href="../api_reference/C/envset_flags.html#envset_flags_DB_TXN_NOSYNC" class="olink">DB_TXN_NOSYNC</a> + flag to <a href="../api_reference/C/envset_flags.html" class="olink">DB_ENV->set_flags()</a> when opening a transaction region + changes the behavior of transactions to not write or + synchronously flush the log during transaction commit. + </p> + <p> + This change may significantly increase application + transactional throughput. However, it means that although + transactions will continue to exhibit the ACI (atomicity, + consistency, and isolation) properties, they will not have D + (durability). Database integrity will be maintained, but it is + possible that some number of the most recently committed + transactions may be undone during recovery instead of being + redone. + </p> </div> <div class="navfooter"> <hr /> @@ -77,9 +85,7 @@ redone.</p> <td width="40%" align="right"> <a accesskey="n" href="txn_limits.html">Next</a></td> </tr> <tr> - <td width="40%" align="left" valign="top">Chapter 19. - The Transaction Subsystem - </td> + <td width="40%" align="left" valign="top">Chapter 19. The Transaction Subsystem </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> |