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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<div id="projectname"><a href="https://www.hdfgroup.org">HDF5</a>
 <span id="projectnumber">1.15.0.bf68e6e</span>
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<a href="#func-members">Functions</a> </div>
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<div class="title">Metadata Cache<div class="ingroups"><a class="el" href="group___h5_f.html">Files (H5F)</a></div></div> </div>
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<a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
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<img id="dynsection-0-trigger" src="closed.png" alt="+"/> Collaboration diagram for Metadata Cache:</div>
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<table class="memberdecls">
<tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="func-members"></a>
Functions</h2></td></tr>
<tr class="memitem:gaa67f127242d4aaf244ae8ac4a1fe6a59"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___m_d_c.html#gaa67f127242d4aaf244ae8ac4a1fe6a59">H5Fget_mdc_config</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> file_id, <a class="el" href="struct_h5_a_c__cache__config__t.html">H5AC_cache_config_t</a> *config_ptr)</td></tr>
<tr class="memdesc:gaa67f127242d4aaf244ae8ac4a1fe6a59"><td class="mdescLeft"> </td><td class="mdescRight">Obtains current metadata cache configuration for target file. <a href="group___m_d_c.html#gaa67f127242d4aaf244ae8ac4a1fe6a59">More...</a><br /></td></tr>
<tr class="separator:gaa67f127242d4aaf244ae8ac4a1fe6a59"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga81bc06be69131484eb04d01511b9c8f8"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___m_d_c.html#ga81bc06be69131484eb04d01511b9c8f8">H5Fset_mdc_config</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> file_id, const <a class="el" href="struct_h5_a_c__cache__config__t.html">H5AC_cache_config_t</a> *config_ptr)</td></tr>
<tr class="memdesc:ga81bc06be69131484eb04d01511b9c8f8"><td class="mdescLeft"> </td><td class="mdescRight">Attempts to configure metadata cache of target file. <a href="group___m_d_c.html#ga81bc06be69131484eb04d01511b9c8f8">More...</a><br /></td></tr>
<tr class="separator:ga81bc06be69131484eb04d01511b9c8f8"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:gabea066c3fd924d2cf868ecee66a7c41f"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___m_d_c.html#gabea066c3fd924d2cf868ecee66a7c41f">H5Fget_mdc_hit_rate</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> file_id, double *hit_rate_ptr)</td></tr>
<tr class="memdesc:gabea066c3fd924d2cf868ecee66a7c41f"><td class="mdescLeft"> </td><td class="mdescRight">Obtains target file's metadata cache hit rate. <a href="group___m_d_c.html#gabea066c3fd924d2cf868ecee66a7c41f">More...</a><br /></td></tr>
<tr class="separator:gabea066c3fd924d2cf868ecee66a7c41f"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:gacda6cbd60d3c50b59f801eba4e5a335f"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___m_d_c.html#gacda6cbd60d3c50b59f801eba4e5a335f">H5Fget_mdc_size</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> file_id, size_t *max_size_ptr, size_t *min_clean_size_ptr, size_t *cur_size_ptr, int *cur_num_entries_ptr)</td></tr>
<tr class="memdesc:gacda6cbd60d3c50b59f801eba4e5a335f"><td class="mdescLeft"> </td><td class="mdescRight">Obtains current metadata cache size data for specified file. <a href="group___m_d_c.html#gacda6cbd60d3c50b59f801eba4e5a335f">More...</a><br /></td></tr>
<tr class="separator:gacda6cbd60d3c50b59f801eba4e5a335f"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga6708886c2bb8740327d9078d7840197f"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___m_d_c.html#ga6708886c2bb8740327d9078d7840197f">H5Freset_mdc_hit_rate_stats</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> file_id)</td></tr>
<tr class="memdesc:ga6708886c2bb8740327d9078d7840197f"><td class="mdescLeft"> </td><td class="mdescRight">Resets hit rate statistics counters for the target file. <a href="group___m_d_c.html#ga6708886c2bb8740327d9078d7840197f">More...</a><br /></td></tr>
<tr class="separator:ga6708886c2bb8740327d9078d7840197f"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga378fb5863071278b47070cf205f53e67"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___m_d_c.html#ga378fb5863071278b47070cf205f53e67">H5Fstart_mdc_logging</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> file_id)</td></tr>
<tr class="memdesc:ga378fb5863071278b47070cf205f53e67"><td class="mdescLeft"> </td><td class="mdescRight">Starts logging metadata cache events if logging was previously enabled. <a href="group___m_d_c.html#ga378fb5863071278b47070cf205f53e67">More...</a><br /></td></tr>
<tr class="separator:ga378fb5863071278b47070cf205f53e67"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga78627b23010f82002b837f4d312bf234"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___m_d_c.html#ga78627b23010f82002b837f4d312bf234">H5Fstop_mdc_logging</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> file_id)</td></tr>
<tr class="memdesc:ga78627b23010f82002b837f4d312bf234"><td class="mdescLeft"> </td><td class="mdescRight">Stops logging metadata cache events if logging was previously enabled and is currently ongoing. <a href="group___m_d_c.html#ga78627b23010f82002b837f4d312bf234">More...</a><br /></td></tr>
<tr class="separator:ga78627b23010f82002b837f4d312bf234"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga998ebdc7b5190cf3d0fdf2fbe71e9780"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___m_d_c.html#ga998ebdc7b5190cf3d0fdf2fbe71e9780">H5Fget_mdc_logging_status</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> file_id, <a class="el" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> *is_enabled, <a class="el" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> *is_currently_logging)</td></tr>
<tr class="memdesc:ga998ebdc7b5190cf3d0fdf2fbe71e9780"><td class="mdescLeft"> </td><td class="mdescRight">Gets the current metadata cache logging status. <a href="group___m_d_c.html#ga998ebdc7b5190cf3d0fdf2fbe71e9780">More...</a><br /></td></tr>
<tr class="separator:ga998ebdc7b5190cf3d0fdf2fbe71e9780"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga7b37da15ff80c4aa5c275649f1f45b0a"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___m_d_c.html#ga7b37da15ff80c4aa5c275649f1f45b0a">H5Fget_mdc_image_info</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> file_id, <a class="el" href="_h5public_8h.html#a8c86e866f40d7167cf9a1934c72b856f">haddr_t</a> *image_addr, <a class="el" href="_h5public_8h.html#a7f81cce70fb546af88da24d9285d3c1c">hsize_t</a> *image_size)</td></tr>
<tr class="memdesc:ga7b37da15ff80c4aa5c275649f1f45b0a"><td class="mdescLeft"> </td><td class="mdescRight">Obtains information about a cache image if it exists. <a href="group___m_d_c.html#ga7b37da15ff80c4aa5c275649f1f45b0a">More...</a><br /></td></tr>
<tr class="separator:ga7b37da15ff80c4aa5c275649f1f45b0a"><td class="memSeparator" colspan="2"> </td></tr>
</table>
<h2 class="groupheader">Function Documentation</h2>
<a id="gaa67f127242d4aaf244ae8ac4a1fe6a59"></a>
<h2 class="memtitle"><span class="permalink"><a href="#gaa67f127242d4aaf244ae8ac4a1fe6a59">◆ </a></span>H5Fget_mdc_config()</h2>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> H5Fget_mdc_config </td>
<td>(</td>
<td class="paramtype"><a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> </td>
<td class="paramname"><em>file_id</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="struct_h5_a_c__cache__config__t.html">H5AC_cache_config_t</a> * </td>
<td class="paramname"><em>config_ptr</em> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td>
</tr>
</table>
</div><div class="memdoc">
<p>Obtains current metadata cache configuration for target file. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">file_id</td><td>File identifier </td></tr>
<tr><td class="paramdir">[in,out]</td><td class="paramname">config_ptr</td><td>Pointer to the <a class="el" href="struct_h5_a_c__cache__config__t.html">H5AC_cache_config_t</a> instance in which the current metadata cache configuration is to be reported. The fields of this structure are discussed <a class="el" href="_h5_a_c-cache-config-t.html">here</a>. </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>Returns a non-negative value if successful; otherwise, returns a negative value.</dd></dl>
<dl class="section note"><dt>Note</dt><dd>The <code>in</code> direction applies only to the <a class="el" href="struct_h5_a_c__cache__config__t.html#aad880fc4455c253781e8968f2239d56f">H5AC_cache_config_t::version</a> field. All other fields are out parameters.</dd></dl>
<p><a class="el" href="group___m_d_c.html#gaa67f127242d4aaf244ae8ac4a1fe6a59" title="Obtains current metadata cache configuration for target file.">H5Fget_mdc_config()</a> loads the current metadata cache configuration into the instance of <a class="el" href="struct_h5_a_c__cache__config__t.html">H5AC_cache_config_t</a> pointed to by the <code>config_ptr</code> parameter.<br />
The fields of the <a class="el" href="struct_h5_a_c__cache__config__t.html">H5AC_cache_config_t</a> structure are shown below: </p><div class="fragment"><div class="line"><span class="keyword">typedef</span> <span class="keyword">struct </span><a class="code" href="struct_h5_a_c__cache__config__t.html">H5AC_cache_config_t</a> {</div>
<div class="line"> <span class="comment">/* general configuration fields: */</span></div>
<div class="line"> <span class="keywordtype">int</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#aad880fc4455c253781e8968f2239d56f">version</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#aab04b3e770d1c2decc03f6fd94b64b17">rpt_fcn_enabled</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a6c03d051d5efb0e64bdca5d0b354a8b1">open_trace_file</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#aced3486ae892a53209b7aae069a34be9">close_trace_file</a>;</div>
<div class="line"> <span class="keywordtype">char</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a92e7d20eb2b7b353961c64558ddac080">trace_file_name</a>[<a class="code" href="_h5_a_cpublic_8h.html#a717f1f3545cfc3d1b2208c96cc0c3bd3">H5AC__MAX_TRACE_FILE_NAME_LEN</a> + 1];</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a3d6e32c7a9bf8f65848c6840e1de8c6e">evictions_enabled</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a707198a337ece01a37dfec6e01275d82">set_initial_size</a>;</div>
<div class="line"> <span class="keywordtype">size_t</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a649236e7dd714855a50f122aa5caca9f">initial_size</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#abd805b98f873c1720f34a0ce937838fd">min_clean_fraction</a>;</div>
<div class="line"> <span class="keywordtype">size_t</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#af4728438dee601cb2554d9bf18d78a43">max_size</a>;</div>
<div class="line"> <span class="keywordtype">size_t</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#af99ca22b80e05fd5b3603806348ab647">min_size</a>;</div>
<div class="line"> <span class="keywordtype">long</span> <span class="keywordtype">int</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#ac998e51b01e0eef09d9a29c43f97e4bf">epoch_length</a>;</div>
<div class="line"> </div>
<div class="line"> <span class="comment">/* size increase control fields: */</span></div>
<div class="line"> <span class="keyword">enum</span> <a class="code" href="_h5_cpublic_8h.html#a040d488146ff1ca0a82209e9af3918fa">H5C_cache_incr_mode</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#ae825aaf759060239e92170d20eb97d26">incr_mode</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a20f323fcb4747fc7228d2d74bb965586">lower_hr_threshold</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#ac504dff76b24ab9f15536c51aec9fbbb">increment</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a322f2a955e71ab7ede483e991e76f806">apply_max_increment</a>;</div>
<div class="line"> <span class="keywordtype">size_t</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#ad5a729f1d611f2780679a35b3524052c">max_increment</a>;</div>
<div class="line"> <span class="keyword">enum</span> <a class="code" href="_h5_cpublic_8h.html#aaaa13ca7756d135b7df6d5a6779ee908">H5C_cache_flash_incr_mode</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a0e25a1dc2c695bea335df0e23ed6363c">flash_incr_mode</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a77b1812e0407c9122db524462a5c9633">flash_multiple</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a95fb1e03a77ef5c109d0c851416ced55">flash_threshold</a>;</div>
<div class="line"> </div>
<div class="line"> <span class="comment">/* size decrease control fields: */</span></div>
<div class="line"> <span class="keyword">enum</span> <a class="code" href="_h5_cpublic_8h.html#a4f8534794ad9a977185a5d608c0af04f">H5C_cache_decr_mode</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a5df68196b281c19d8ab7da0788566aec">decr_mode</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a84a5ff4ac69196aa27c14f6f796db596">upper_hr_threshold</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a54007d3f2afb718b437f499a5c8b46d9">decrement</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#ac2c89a735413e4c36d6f463c4890ab42">apply_max_decrement</a>;</div>
<div class="line"> <span class="keywordtype">size_t</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a75e875a61c9da7f82482d0f6fe6e7152">max_decrement</a>;</div>
<div class="line"> <span class="keywordtype">int</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a7ac41e345300bdecd9943e855d55b71b">epochs_before_eviction</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a6c5cff8e8a21230cc7f21859d8d6bd22">apply_empty_reserve</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a9c1ae995513b55737aad09e11beff733">empty_reserve</a>;</div>
<div class="line"> </div>
<div class="line"> <span class="comment">/* parallel configuration fields: */</span></div>
<div class="line"> <span class="keywordtype">size_t</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a8e3c2a2d300b7a8f8d3705fc5e59a3c1">dirty_bytes_threshold</a>;</div>
<div class="line"> <span class="keywordtype">int</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a83a536128dbb7785b2553c294f33d1fe">metadata_write_strategy</a>;</div>
<div class="line">} <a class="code" href="struct_h5_a_c__cache__config__t.html">H5AC_cache_config_t</a>;</div>
<div class="ttc" id="a_h5_a_cpublic_8h_html_a717f1f3545cfc3d1b2208c96cc0c3bd3"><div class="ttname"><a href="_h5_a_cpublic_8h.html#a717f1f3545cfc3d1b2208c96cc0c3bd3">H5AC__MAX_TRACE_FILE_NAME_LEN</a></div><div class="ttdeci">#define H5AC__MAX_TRACE_FILE_NAME_LEN</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:432</div></div>
<div class="ttc" id="a_h5_cpublic_8h_html_a040d488146ff1ca0a82209e9af3918fa"><div class="ttname"><a href="_h5_cpublic_8h.html#a040d488146ff1ca0a82209e9af3918fa">H5C_cache_incr_mode</a></div><div class="ttdeci">H5C_cache_incr_mode</div><div class="ttdef"><b>Definition:</b> H5Cpublic.h:26</div></div>
<div class="ttc" id="a_h5_cpublic_8h_html_a4f8534794ad9a977185a5d608c0af04f"><div class="ttname"><a href="_h5_cpublic_8h.html#a4f8534794ad9a977185a5d608c0af04f">H5C_cache_decr_mode</a></div><div class="ttdeci">H5C_cache_decr_mode</div><div class="ttdef"><b>Definition:</b> H5Cpublic.h:42</div></div>
<div class="ttc" id="a_h5_cpublic_8h_html_aaaa13ca7756d135b7df6d5a6779ee908"><div class="ttname"><a href="_h5_cpublic_8h.html#aaaa13ca7756d135b7df6d5a6779ee908">H5C_cache_flash_incr_mode</a></div><div class="ttdeci">H5C_cache_flash_incr_mode</div><div class="ttdef"><b>Definition:</b> H5Cpublic.h:34</div></div>
<div class="ttc" id="a_h5public_8h_html_ad470b00eccd2115c707c02de5fa1120d"><div class="ttname"><a href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a></div><div class="ttdeci">bool hbool_t</div><div class="ttdef"><b>Definition:</b> H5public.h:243</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html">H5AC_cache_config_t</a></div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:462</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a0e25a1dc2c695bea335df0e23ed6363c"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a0e25a1dc2c695bea335df0e23ed6363c">H5AC_cache_config_t::flash_incr_mode</a></div><div class="ttdeci">enum H5C_cache_flash_incr_mode flash_incr_mode</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:615</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a20f323fcb4747fc7228d2d74bb965586"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a20f323fcb4747fc7228d2d74bb965586">H5AC_cache_config_t::lower_hr_threshold</a></div><div class="ttdeci">double lower_hr_threshold</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:585</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a322f2a955e71ab7ede483e991e76f806"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a322f2a955e71ab7ede483e991e76f806">H5AC_cache_config_t::apply_max_increment</a></div><div class="ttdeci">hbool_t apply_max_increment</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:607</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a3d6e32c7a9bf8f65848c6840e1de8c6e"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a3d6e32c7a9bf8f65848c6840e1de8c6e">H5AC_cache_config_t::evictions_enabled</a></div><div class="ttdeci">hbool_t evictions_enabled</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:526</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a54007d3f2afb718b437f499a5c8b46d9"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a54007d3f2afb718b437f499a5c8b46d9">H5AC_cache_config_t::decrement</a></div><div class="ttdeci">double decrement</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:657</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a5df68196b281c19d8ab7da0788566aec"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a5df68196b281c19d8ab7da0788566aec">H5AC_cache_config_t::decr_mode</a></div><div class="ttdeci">enum H5C_cache_decr_mode decr_mode</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:638</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a649236e7dd714855a50f122aa5caca9f"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a649236e7dd714855a50f122aa5caca9f">H5AC_cache_config_t::initial_size</a></div><div class="ttdeci">size_t initial_size</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:550</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a6c03d051d5efb0e64bdca5d0b354a8b1"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a6c03d051d5efb0e64bdca5d0b354a8b1">H5AC_cache_config_t::open_trace_file</a></div><div class="ttdeci">hbool_t open_trace_file</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:478</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a6c5cff8e8a21230cc7f21859d8d6bd22"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a6c5cff8e8a21230cc7f21859d8d6bd22">H5AC_cache_config_t::apply_empty_reserve</a></div><div class="ttdeci">hbool_t apply_empty_reserve</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:683</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a707198a337ece01a37dfec6e01275d82"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a707198a337ece01a37dfec6e01275d82">H5AC_cache_config_t::set_initial_size</a></div><div class="ttdeci">hbool_t set_initial_size</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:546</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a75e875a61c9da7f82482d0f6fe6e7152"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a75e875a61c9da7f82482d0f6fe6e7152">H5AC_cache_config_t::max_decrement</a></div><div class="ttdeci">size_t max_decrement</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:673</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a77b1812e0407c9122db524462a5c9633"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a77b1812e0407c9122db524462a5c9633">H5AC_cache_config_t::flash_multiple</a></div><div class="ttdeci">double flash_multiple</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:620</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a7ac41e345300bdecd9943e855d55b71b"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a7ac41e345300bdecd9943e855d55b71b">H5AC_cache_config_t::epochs_before_eviction</a></div><div class="ttdeci">int epochs_before_eviction</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:677</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a83a536128dbb7785b2553c294f33d1fe"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a83a536128dbb7785b2553c294f33d1fe">H5AC_cache_config_t::metadata_write_strategy</a></div><div class="ttdeci">int metadata_write_strategy</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:707</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a84a5ff4ac69196aa27c14f6f796db596"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a84a5ff4ac69196aa27c14f6f796db596">H5AC_cache_config_t::upper_hr_threshold</a></div><div class="ttdeci">double upper_hr_threshold</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:643</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a8e3c2a2d300b7a8f8d3705fc5e59a3c1"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a8e3c2a2d300b7a8f8d3705fc5e59a3c1">H5AC_cache_config_t::dirty_bytes_threshold</a></div><div class="ttdeci">size_t dirty_bytes_threshold</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:696</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a92e7d20eb2b7b353961c64558ddac080"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a92e7d20eb2b7b353961c64558ddac080">H5AC_cache_config_t::trace_file_name</a></div><div class="ttdeci">char trace_file_name[1024+1]</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:511</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a95fb1e03a77ef5c109d0c851416ced55"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a95fb1e03a77ef5c109d0c851416ced55">H5AC_cache_config_t::flash_threshold</a></div><div class="ttdeci">double flash_threshold</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:629</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_a9c1ae995513b55737aad09e11beff733"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#a9c1ae995513b55737aad09e11beff733">H5AC_cache_config_t::empty_reserve</a></div><div class="ttdeci">double empty_reserve</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:687</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_aab04b3e770d1c2decc03f6fd94b64b17"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#aab04b3e770d1c2decc03f6fd94b64b17">H5AC_cache_config_t::rpt_fcn_enabled</a></div><div class="ttdeci">hbool_t rpt_fcn_enabled</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:470</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_aad880fc4455c253781e8968f2239d56f"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#aad880fc4455c253781e8968f2239d56f">H5AC_cache_config_t::version</a></div><div class="ttdeci">int version</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:465</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_abd805b98f873c1720f34a0ce937838fd"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#abd805b98f873c1720f34a0ce937838fd">H5AC_cache_config_t::min_clean_fraction</a></div><div class="ttdeci">double min_clean_fraction</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:556</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_ac2c89a735413e4c36d6f463c4890ab42"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#ac2c89a735413e4c36d6f463c4890ab42">H5AC_cache_config_t::apply_max_decrement</a></div><div class="ttdeci">hbool_t apply_max_decrement</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:669</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_ac504dff76b24ab9f15536c51aec9fbbb"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#ac504dff76b24ab9f15536c51aec9fbbb">H5AC_cache_config_t::increment</a></div><div class="ttdeci">double increment</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:595</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_ac998e51b01e0eef09d9a29c43f97e4bf"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#ac998e51b01e0eef09d9a29c43f97e4bf">H5AC_cache_config_t::epoch_length</a></div><div class="ttdeci">long int epoch_length</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:573</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_aced3486ae892a53209b7aae069a34be9"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#aced3486ae892a53209b7aae069a34be9">H5AC_cache_config_t::close_trace_file</a></div><div class="ttdeci">hbool_t close_trace_file</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:499</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_ad5a729f1d611f2780679a35b3524052c"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#ad5a729f1d611f2780679a35b3524052c">H5AC_cache_config_t::max_increment</a></div><div class="ttdeci">size_t max_increment</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:611</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_ae825aaf759060239e92170d20eb97d26"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#ae825aaf759060239e92170d20eb97d26">H5AC_cache_config_t::incr_mode</a></div><div class="ttdeci">enum H5C_cache_incr_mode incr_mode</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:580</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_af4728438dee601cb2554d9bf18d78a43"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#af4728438dee601cb2554d9bf18d78a43">H5AC_cache_config_t::max_size</a></div><div class="ttdeci">size_t max_size</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:565</div></div>
<div class="ttc" id="astruct_h5_a_c__cache__config__t_html_af99ca22b80e05fd5b3603806348ab647"><div class="ttname"><a href="struct_h5_a_c__cache__config__t.html#af99ca22b80e05fd5b3603806348ab647">H5AC_cache_config_t::min_size</a></div><div class="ttdeci">size_t min_size</div><div class="ttdef"><b>Definition:</b> H5ACpublic.h:569</div></div>
</div><!-- fragment --><p> (Click on a enumerator, field, or type for more information.)</p>
<dl class="section since"><dt>Since</dt><dd>1.8.0 </dd></dl>
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<h2 class="memtitle"><span class="permalink"><a href="#gabea066c3fd924d2cf868ecee66a7c41f">◆ </a></span>H5Fget_mdc_hit_rate()</h2>
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<td class="memname"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> H5Fget_mdc_hit_rate </td>
<td>(</td>
<td class="paramtype"><a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> </td>
<td class="paramname"><em>file_id</em>, </td>
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<td class="paramtype">double * </td>
<td class="paramname"><em>hit_rate_ptr</em> </td>
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<p>Obtains target file's metadata cache hit rate. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">file_id</td><td>File identifier </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">hit_rate_ptr</td><td>Pointer to the double in which the hit rate is returned. Note that <code>hit_rate_ptr</code> is undefined if the API call fails </td></tr>
</table>
</dd>
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<dl class="section return"><dt>Returns</dt><dd>Returns a non-negative value if successful; otherwise, returns a negative value.</dd></dl>
<p><a class="el" href="group___m_d_c.html#gabea066c3fd924d2cf868ecee66a7c41f" title="Obtains target file's metadata cache hit rate.">H5Fget_mdc_hit_rate()</a> queries the metadata cache of the target file to obtain its hit rate <code>(cache hits / (cache hits + cache misses))</code> since the last time hit rate statistics were reset. If the cache has not been accessed since the last time the hit rate stats were reset, the hit rate is defined to be 0.0.</p>
<p>The hit rate stats can be reset either manually (via <a class="el" href="group___m_d_c.html#ga6708886c2bb8740327d9078d7840197f" title="Resets hit rate statistics counters for the target file.">H5Freset_mdc_hit_rate_stats()</a>), or automatically. If the cache's adaptive resize code is enabled, the hit rate stats will be reset once per epoch. If they are reset manually as well, the cache may behave oddly.</p>
<p>See the overview of the metadata cache in the special topics section of the user manual for details on the metadata cache and its adaptive resize algorithms. </p>
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<h2 class="memtitle"><span class="permalink"><a href="#ga7b37da15ff80c4aa5c275649f1f45b0a">◆ </a></span>H5Fget_mdc_image_info()</h2>
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<td class="memname"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> H5Fget_mdc_image_info </td>
<td>(</td>
<td class="paramtype"><a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> </td>
<td class="paramname"><em>file_id</em>, </td>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="_h5public_8h.html#a8c86e866f40d7167cf9a1934c72b856f">haddr_t</a> * </td>
<td class="paramname"><em>image_addr</em>, </td>
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<td class="paramtype"><a class="el" href="_h5public_8h.html#a7f81cce70fb546af88da24d9285d3c1c">hsize_t</a> * </td>
<td class="paramname"><em>image_size</em> </td>
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<p>Obtains information about a cache image if it exists. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">file_id</td><td>File identifier </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">image_addr</td><td>Offset of the cache image if it exists, or <a class="el" href="_h5public_8h.html#a676244a60b85ee8bbd111afd4a8fce3c">HADDR_UNDEF</a> if it does not </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">image_size</td><td>Length of the cache image if it exists, or 0 if it does not </td></tr>
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<dl class="section return"><dt>Returns</dt><dd>Returns a non-negative value if successful; otherwise, returns a negative value.</dd></dl>
<p><a class="el" href="group___m_d_c.html#ga7b37da15ff80c4aa5c275649f1f45b0a" title="Obtains information about a cache image if it exists.">H5Fget_mdc_image_info()</a> returns information about a cache image if it exists.</p>
<p>When an HDF5 file is opened in Read/Write mode, any metadata cache image will be read and deleted from the file on the first metadata cache access (or, if persistent free space managers are enabled, on the first file space allocation / deallocation, or read of free space manager status, whichever comes first).</p>
<p>Thus, if the file is opened Read/Write, <a class="el" href="group___m_d_c.html#ga7b37da15ff80c4aa5c275649f1f45b0a" title="Obtains information about a cache image if it exists.">H5Fget_mdc_image_info()</a> should be called immediately after file open and before any other operation. If <a class="el" href="group___m_d_c.html#ga7b37da15ff80c4aa5c275649f1f45b0a" title="Obtains information about a cache image if it exists.">H5Fget_mdc_image_info()</a> is called after the cache image is loaded, it will correctly report that no cache image exists, as the image will have already been read and deleted from the file. In the Read Only case, the function may be called at any time, as any cache image will not be deleted from the file. </p>
<dl class="section since"><dt>Since</dt><dd>1.10.1 </dd></dl>
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<h2 class="memtitle"><span class="permalink"><a href="#ga998ebdc7b5190cf3d0fdf2fbe71e9780">◆ </a></span>H5Fget_mdc_logging_status()</h2>
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<td class="memname"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> H5Fget_mdc_logging_status </td>
<td>(</td>
<td class="paramtype"><a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> </td>
<td class="paramname"><em>file_id</em>, </td>
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<td class="paramtype"><a class="el" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> * </td>
<td class="paramname"><em>is_enabled</em>, </td>
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<td class="paramtype"><a class="el" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> * </td>
<td class="paramname"><em>is_currently_logging</em> </td>
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<p>Gets the current metadata cache logging status. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">file_id</td><td>File identifier </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">is_enabled</td><td>Whether logging is enabled </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">is_currently_logging</td><td>Whether events are currently being logged </td></tr>
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<dl class="section return"><dt>Returns</dt><dd>Returns a non-negative value if successful; otherwise, returns a negative value.</dd></dl>
<p>The metadata cache is a central part of the HDF5 library through which all <em>file metadata</em> reads and writes take place. File metadata is normally invisible to the user and is used by the library for purposes such as locating and indexing data. File metadata should not be confused with user metadata, which consists of attributes created by users and attached to HDF5 objects such as datasets via H5A API calls.</p>
<p>Due to the complexity of the cache, a trace/logging feature has been created that can be used by HDF5 developers for debugging and performance analysis. The functions that control this functionality will normally be of use to a very limited number of developers outside of The HDF Group. The functions have been documented to help users create logs that can be sent with bug reports.</p>
<p>Control of the log functionality is straightforward. Logging is enabled via the <a class="el" href="group___f_a_p_l.html#ga4d7206c5679d7243410058eceae59b2c" title="Sets metadata cache logging options.">H5Pset_mdc_log_options()</a> function, which will modify the file access property list used to open or create a file. This function has a flag that determines whether logging begins at file open or starts in a paused state. Log messages can then be controlled via the <a class="el" href="group___m_d_c.html#ga378fb5863071278b47070cf205f53e67" title="Starts logging metadata cache events if logging was previously enabled.">H5Fstart_mdc_logging()</a> and <a class="el" href="group___m_d_c.html#ga78627b23010f82002b837f4d312bf234" title="Stops logging metadata cache events if logging was previously enabled and is currently ongoing.">H5Fstop_mdc_logging()</a> functions. <a class="el" href="group___f_a_p_l.html#gaa3a1ca6e294cc5074933239cc3d0e4a3" title="Gets metadata cache logging options.">H5Pget_mdc_log_options()</a> can be used to examine a file access property list, and <a class="el" href="group___m_d_c.html#ga998ebdc7b5190cf3d0fdf2fbe71e9780" title="Gets the current metadata cache logging status.">H5Fget_mdc_logging_status()</a> will return the current state of the logging flags.</p>
<p>The log format is described in the <a href="https://portal.hdfgroup.org/display/HDF5/H5F_START_MDC_LOGGING">Metadata Cache Logging</a> document.</p>
<dl class="section note"><dt>Note</dt><dd>Unlike <a class="el" href="group___m_d_c.html#ga378fb5863071278b47070cf205f53e67" title="Starts logging metadata cache events if logging was previously enabled.">H5Fstart_mdc_logging()</a> and <a class="el" href="group___m_d_c.html#ga78627b23010f82002b837f4d312bf234" title="Stops logging metadata cache events if logging was previously enabled and is currently ongoing.">H5Fstop_mdc_logging()</a>, this function can be called on any open file identifier.</dd></dl>
<dl class="section since"><dt>Since</dt><dd>1.10.0 </dd></dl>
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<h2 class="memtitle"><span class="permalink"><a href="#gacda6cbd60d3c50b59f801eba4e5a335f">◆ </a></span>H5Fget_mdc_size()</h2>
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<td class="memname"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> H5Fget_mdc_size </td>
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<td class="paramtype"><a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> </td>
<td class="paramname"><em>file_id</em>, </td>
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<td class="paramtype">size_t * </td>
<td class="paramname"><em>max_size_ptr</em>, </td>
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<td class="paramtype">size_t * </td>
<td class="paramname"><em>min_clean_size_ptr</em>, </td>
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<td class="paramtype">size_t * </td>
<td class="paramname"><em>cur_size_ptr</em>, </td>
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<td class="paramtype">int * </td>
<td class="paramname"><em>cur_num_entries_ptr</em> </td>
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<p>Obtains current metadata cache size data for specified file. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">file_id</td><td>File identifier </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">max_size_ptr</td><td>Pointer to the location in which the current cache maximum size is to be returned, or NULL if this datum is not desired </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">min_clean_size_ptr</td><td>Pointer to the location in which the current cache minimum clean size is to be returned, or NULL if that datum is not desired </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">cur_size_ptr</td><td>Pointer to the location in which the current cache size is to be returned, or NULL if that datum is not desired </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">cur_num_entries_ptr</td><td>Pointer to the location in which the current number of entries in the cache is to be returned, or NULL if that datum is not desired </td></tr>
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<dl class="section return"><dt>Returns</dt><dd>Returns a non-negative value if successful; otherwise, returns a negative value.</dd></dl>
<p><a class="el" href="group___m_d_c.html#gacda6cbd60d3c50b59f801eba4e5a335f" title="Obtains current metadata cache size data for specified file.">H5Fget_mdc_size()</a> queries the metadata cache of the target file for the desired size information, and returns this information in the locations indicated by the pointer parameters. If any pointer parameter is NULL, the associated data is not returned.</p>
<p>If the API call fails, the values returned via the pointer parameters are undefined.</p>
<p>If adaptive cache resizing is enabled, the cache maximum size and minimum clean size may change at the end of each epoch. Current size and current number of entries can change on each cache access.</p>
<p>Current size can exceed maximum size under certain conditions. See the overview of the metadata cache in the special topics section of the user manual for a discussion of this. </p>
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<h2 class="memtitle"><span class="permalink"><a href="#ga6708886c2bb8740327d9078d7840197f">◆ </a></span>H5Freset_mdc_hit_rate_stats()</h2>
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<td class="memname"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> H5Freset_mdc_hit_rate_stats </td>
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<p>Resets hit rate statistics counters for the target file. </p>
<dl class="params"><dt>Parameters</dt><dd>
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<tr><td class="paramdir">[in]</td><td class="paramname">file_id</td><td>File identifier </td></tr>
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<dl class="section return"><dt>Returns</dt><dd>Returns a non-negative value if successful; otherwise, returns a negative value.</dd></dl>
<p><a class="el" href="group___m_d_c.html#ga6708886c2bb8740327d9078d7840197f" title="Resets hit rate statistics counters for the target file.">H5Freset_mdc_hit_rate_stats()</a> resets the hit rate statistics counters in the metadata cache associated with the specified file.</p>
<p>If the adaptive cache resizing code is enabled, the hit rate statistics are reset at the beginning of each epoch. This API call allows you to do the same thing from your program.</p>
<p>The adaptive cache resizing code may behave oddly if you use this call when adaptive cache resizing is enabled. However, the call should be useful if you choose to control metadata cache size from your program.</p>
<p>See <a href="https://portal.hdfgroup.org/display/HDF5/Metadata+Caching+in+HDF5">Metadata Caching in HDF5</a> for details about the metadata cache and the adaptive cache resizing algorithms. If you have not read, understood, and thought about the material covered in that documentation, you should not be using this API call. </p>
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<h2 class="memtitle"><span class="permalink"><a href="#ga81bc06be69131484eb04d01511b9c8f8">◆ </a></span>H5Fset_mdc_config()</h2>
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<td class="paramname"><em>file_id</em>, </td>
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<td class="paramtype">const <a class="el" href="struct_h5_a_c__cache__config__t.html">H5AC_cache_config_t</a> * </td>
<td class="paramname"><em>config_ptr</em> </td>
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<p>Attempts to configure metadata cache of target file. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">file_id</td><td>File identifier </td></tr>
<tr><td class="paramdir">[in,out]</td><td class="paramname">config_ptr</td><td>Pointer to the <a class="el" href="struct_h5_a_c__cache__config__t.html">H5AC_cache_config_t</a> instance containing the desired configuration. The fields of this structure are discussed <a class="el" href="_h5_a_c-cache-config-t.html">here</a>. </td></tr>
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<dl class="section return"><dt>Returns</dt><dd>Returns a non-negative value if successful; otherwise, returns a negative value.</dd></dl>
<p><a class="el" href="group___m_d_c.html#ga81bc06be69131484eb04d01511b9c8f8" title="Attempts to configure metadata cache of target file.">H5Fset_mdc_config()</a> attempts to configure the file's metadata cache according configuration supplied in <code>config_ptr</code>. </p><div class="fragment"><div class="line"><span class="keyword">typedef</span> <span class="keyword">struct </span><a class="code" href="struct_h5_a_c__cache__config__t.html">H5AC_cache_config_t</a> {</div>
<div class="line"> <span class="comment">/* general configuration fields: */</span></div>
<div class="line"> <span class="keywordtype">int</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#aad880fc4455c253781e8968f2239d56f">version</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#aab04b3e770d1c2decc03f6fd94b64b17">rpt_fcn_enabled</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a6c03d051d5efb0e64bdca5d0b354a8b1">open_trace_file</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#aced3486ae892a53209b7aae069a34be9">close_trace_file</a>;</div>
<div class="line"> <span class="keywordtype">char</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a92e7d20eb2b7b353961c64558ddac080">trace_file_name</a>[<a class="code" href="_h5_a_cpublic_8h.html#a717f1f3545cfc3d1b2208c96cc0c3bd3">H5AC__MAX_TRACE_FILE_NAME_LEN</a> + 1];</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a3d6e32c7a9bf8f65848c6840e1de8c6e">evictions_enabled</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a707198a337ece01a37dfec6e01275d82">set_initial_size</a>;</div>
<div class="line"> <span class="keywordtype">size_t</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a649236e7dd714855a50f122aa5caca9f">initial_size</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#abd805b98f873c1720f34a0ce937838fd">min_clean_fraction</a>;</div>
<div class="line"> <span class="keywordtype">size_t</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#af4728438dee601cb2554d9bf18d78a43">max_size</a>;</div>
<div class="line"> <span class="keywordtype">size_t</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#af99ca22b80e05fd5b3603806348ab647">min_size</a>;</div>
<div class="line"> <span class="keywordtype">long</span> <span class="keywordtype">int</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#ac998e51b01e0eef09d9a29c43f97e4bf">epoch_length</a>;</div>
<div class="line"> </div>
<div class="line"> <span class="comment">/* size increase control fields: */</span></div>
<div class="line"> <span class="keyword">enum</span> <a class="code" href="_h5_cpublic_8h.html#a040d488146ff1ca0a82209e9af3918fa">H5C_cache_incr_mode</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#ae825aaf759060239e92170d20eb97d26">incr_mode</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a20f323fcb4747fc7228d2d74bb965586">lower_hr_threshold</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#ac504dff76b24ab9f15536c51aec9fbbb">increment</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a322f2a955e71ab7ede483e991e76f806">apply_max_increment</a>;</div>
<div class="line"> <span class="keywordtype">size_t</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#ad5a729f1d611f2780679a35b3524052c">max_increment</a>;</div>
<div class="line"> <span class="keyword">enum</span> <a class="code" href="_h5_cpublic_8h.html#aaaa13ca7756d135b7df6d5a6779ee908">H5C_cache_flash_incr_mode</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a0e25a1dc2c695bea335df0e23ed6363c">flash_incr_mode</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a77b1812e0407c9122db524462a5c9633">flash_multiple</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a95fb1e03a77ef5c109d0c851416ced55">flash_threshold</a>;</div>
<div class="line"> </div>
<div class="line"> <span class="comment">/* size decrease control fields: */</span></div>
<div class="line"> <span class="keyword">enum</span> <a class="code" href="_h5_cpublic_8h.html#a4f8534794ad9a977185a5d608c0af04f">H5C_cache_decr_mode</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a5df68196b281c19d8ab7da0788566aec">decr_mode</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a84a5ff4ac69196aa27c14f6f796db596">upper_hr_threshold</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a54007d3f2afb718b437f499a5c8b46d9">decrement</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#ac2c89a735413e4c36d6f463c4890ab42">apply_max_decrement</a>;</div>
<div class="line"> <span class="keywordtype">size_t</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a75e875a61c9da7f82482d0f6fe6e7152">max_decrement</a>;</div>
<div class="line"> <span class="keywordtype">int</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a7ac41e345300bdecd9943e855d55b71b">epochs_before_eviction</a>;</div>
<div class="line"> <a class="code" href="_h5public_8h.html#ad470b00eccd2115c707c02de5fa1120d">hbool_t</a> <a class="code" href="struct_h5_a_c__cache__config__t.html#a6c5cff8e8a21230cc7f21859d8d6bd22">apply_empty_reserve</a>;</div>
<div class="line"> <span class="keywordtype">double</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a9c1ae995513b55737aad09e11beff733">empty_reserve</a>;</div>
<div class="line"> </div>
<div class="line"> <span class="comment">/* parallel configuration fields: */</span></div>
<div class="line"> <span class="keywordtype">size_t</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a8e3c2a2d300b7a8f8d3705fc5e59a3c1">dirty_bytes_threshold</a>;</div>
<div class="line"> <span class="keywordtype">int</span> <a class="code" href="struct_h5_a_c__cache__config__t.html#a83a536128dbb7785b2553c294f33d1fe">metadata_write_strategy</a>;</div>
<div class="line">} <a class="code" href="struct_h5_a_c__cache__config__t.html">H5AC_cache_config_t</a>;</div>
</div><!-- fragment --><p> (Click on a enumerator, field, or type for more information.)</p>
<dl class="section since"><dt>Since</dt><dd>1.8.0 </dd></dl>
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<h2 class="memtitle"><span class="permalink"><a href="#ga378fb5863071278b47070cf205f53e67">◆ </a></span>H5Fstart_mdc_logging()</h2>
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<td class="memname"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> H5Fstart_mdc_logging </td>
<td>(</td>
<td class="paramtype"><a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> </td>
<td class="paramname"><em>file_id</em></td><td>)</td>
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<p>Starts logging metadata cache events if logging was previously enabled. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">file_id</td><td>File identifier</td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>Returns a non-negative value if successful; otherwise, returns a negative value.</dd></dl>
<p>The metadata cache is a central part of the HDF5 library through which all <em>file metadata</em> reads and writes take place. File metadata is normally invisible to the user and is used by the library for purposes such as locating and indexing data. File metadata should not be confused with user metadata, which consists of attributes created by users and attached to HDF5 objects such as datasets via H5A API calls.</p>
<p>Due to the complexity of the cache, a trace/logging feature has been created that can be used by HDF5 developers for debugging and performance analysis. The functions that control this functionality will normally be of use to a very limited number of developers outside of The HDF Group. The functions have been documented to help users create logs that can be sent with bug reports.</p>
<p>Control of the log functionality is straightforward. Logging is enabled via the <a class="el" href="group___f_a_p_l.html#ga4d7206c5679d7243410058eceae59b2c" title="Sets metadata cache logging options.">H5Pset_mdc_log_options()</a> function, which will modify the file access property list used to open or create a file. This function has a flag that determines whether logging begins at file open or starts in a paused state. Log messages can then be controlled via the <a class="el" href="group___m_d_c.html#ga378fb5863071278b47070cf205f53e67" title="Starts logging metadata cache events if logging was previously enabled.">H5Fstart_mdc_logging()</a> and <a class="el" href="group___m_d_c.html#ga78627b23010f82002b837f4d312bf234" title="Stops logging metadata cache events if logging was previously enabled and is currently ongoing.">H5Fstop_mdc_logging()</a> functions. <a class="el" href="group___f_a_p_l.html#gaa3a1ca6e294cc5074933239cc3d0e4a3" title="Gets metadata cache logging options.">H5Pget_mdc_log_options()</a> can be used to examine a file access property list, and <a class="el" href="group___m_d_c.html#ga998ebdc7b5190cf3d0fdf2fbe71e9780" title="Gets the current metadata cache logging status.">H5Fget_mdc_logging_status()</a> will return the current state of the logging flags.</p>
<p>The log format is described in the <a href="https://portal.hdfgroup.org/display/HDF5/H5F_START_MDC_LOGGING">Metadata Cache Logging</a> document.</p>
<dl class="section note"><dt>Note</dt><dd>Logging can only be started or stopped if metadata cache logging was enabled via <a class="el" href="group___f_a_p_l.html#ga4d7206c5679d7243410058eceae59b2c" title="Sets metadata cache logging options.">H5Pset_mdc_log_options()</a>.<br />
When enabled and currently logging, the overhead of the logging feature will almost certainly be significant.<br />
The log file is opened when the HDF5 file is opened or created and not when this function is called for the first time.<br />
This function opens the log file and starts logging metadata cache operations for a particular file. Calling this function when logging has already been enabled will be considered an error.</dd></dl>
<dl class="section since"><dt>Since</dt><dd>1.10.0 </dd></dl>
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<h2 class="memtitle"><span class="permalink"><a href="#ga78627b23010f82002b837f4d312bf234">◆ </a></span>H5Fstop_mdc_logging()</h2>
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<td class="memname"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> H5Fstop_mdc_logging </td>
<td>(</td>
<td class="paramtype"><a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> </td>
<td class="paramname"><em>file_id</em></td><td>)</td>
<td></td>
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<p>Stops logging metadata cache events if logging was previously enabled and is currently ongoing. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">file_id</td><td>File identifier</td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>Returns a non-negative value if successful; otherwise, returns a negative value.</dd></dl>
<p>The metadata cache is a central part of the HDF5 library through which all <em>file metadata</em> reads and writes take place. File metadata is normally invisible to the user and is used by the library for purposes such as locating and indexing data. File metadata should not be confused with user metadata, which consists of attributes created by users and attached to HDF5 objects such as datasets via H5A API calls.</p>
<p>Due to the complexity of the cache, a trace/logging feature has been created that can be used by HDF5 developers for debugging and performance analysis. The functions that control this functionality will normally be of use to a very limited number of developers outside of The HDF Group. The functions have been documented to help users create logs that can be sent with bug reports.</p>
<p>Control of the log functionality is straightforward. Logging is enabled via the <a class="el" href="group___f_a_p_l.html#ga4d7206c5679d7243410058eceae59b2c" title="Sets metadata cache logging options.">H5Pset_mdc_log_options()</a> function, which will modify the file access property list used to open or create a file. This function has a flag that determines whether logging begins at file open or starts in a paused state. Log messages can then be controlled via the <a class="el" href="group___m_d_c.html#ga378fb5863071278b47070cf205f53e67" title="Starts logging metadata cache events if logging was previously enabled.">H5Fstart_mdc_logging()</a> and <a class="el" href="group___m_d_c.html#ga78627b23010f82002b837f4d312bf234" title="Stops logging metadata cache events if logging was previously enabled and is currently ongoing.">H5Fstop_mdc_logging()</a> functions. <a class="el" href="group___f_a_p_l.html#gaa3a1ca6e294cc5074933239cc3d0e4a3" title="Gets metadata cache logging options.">H5Pget_mdc_log_options()</a> can be used to examine a file access property list, and <a class="el" href="group___m_d_c.html#ga998ebdc7b5190cf3d0fdf2fbe71e9780" title="Gets the current metadata cache logging status.">H5Fget_mdc_logging_status()</a> will return the current state of the logging flags.</p>
<p>The log format is described in the <a href="https://portal.hdfgroup.org/display/HDF5/H5F_START_MDC_LOGGING">Metadata Cache Logging</a> document.</p>
<dl class="section note"><dt>Note</dt><dd>Logging can only be started or stopped if metadata cache logging was enabled via <a class="el" href="group___f_a_p_l.html#ga4d7206c5679d7243410058eceae59b2c" title="Sets metadata cache logging options.">H5Pset_mdc_log_options()</a>.<br />
This function only suspends the logging operations. The log file will remain open and will not be closed until the HDF5 file is closed.</dd></dl>
<dl class="section since"><dt>Since</dt><dd>1.10.0 </dd></dl>
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