diff options
Diffstat (limited to 'lib/stdlib/doc/src/ets.xml')
| -rw-r--r-- | lib/stdlib/doc/src/ets.xml | 39 |
1 files changed, 29 insertions, 10 deletions
diff --git a/lib/stdlib/doc/src/ets.xml b/lib/stdlib/doc/src/ets.xml index dd4a289c61..746f94d3f4 100644 --- a/lib/stdlib/doc/src/ets.xml +++ b/lib/stdlib/doc/src/ets.xml @@ -56,8 +56,8 @@ Even if there are no references to a table from any process, it will not automatically be destroyed unless the owner process terminates. It can be destroyed explicitly by using - <c>delete/1</c>.</p> - <p>Since R13B01, table ownership can be transferred at process termination + <c>delete/1</c>. The default owner is the process that created the + table. Table ownership can be transferred at process termination by using the <seealso marker="#heir">heir</seealso> option or explicitly by calling <seealso marker="#give_away/3">give_away/3</seealso>.</p> <p>Some implementation details:</p> @@ -82,11 +82,15 @@ <c>float()</c> that extends to the same value, hence the key <c>1</c> and the key <c>1.0</c> are regarded as equal in an <c>ordered_set</c> table.</p> - <p>In general, the functions below will exit with reason - <c>badarg</c> if any argument is of the wrong format, or if the - table identifier is invalid.</p> </description> - + <section> + <title>Failure</title> + <p>In general, the functions below will exit with reason + <c>badarg</c> if any argument is of the wrong format, if the + table identifier is invalid or if the operation is denied due to + table access rights (<seealso marker="#protected">protected</seealso> + or <seealso marker="#private">private</seealso>).</p> + </section> <section><marker id="concurrency"></marker> <title>Concurrency</title> <p>This module provides some limited support for concurrent access. @@ -481,6 +485,9 @@ Error: fun containing local Erlang function calls <item><c>Item=protection, Value=public|protected|private</c> <br></br> The table access rights.</item> + <item><c>Item=compressed, Value=true|false</c> <br></br> + + Indicates if the table is compressed or not.</item> </list> </desc> </func> @@ -947,9 +954,10 @@ ets:select(Table,MatchSpec),</code> <type> <v>Name = atom()</v> <v>Options = [Option]</v> - <v> Option = Type | Access | named_table | {keypos,Pos} | {heir,pid(),HeirData} | {heir,none} | {write_concurrency,bool()}</v> + <v> Option = Type | Access | named_table | {keypos,Pos} | {heir,pid(),HeirData} | {heir,none} | Tweaks</v> <v> Type = set | ordered_set | bag | duplicate_bag</v> <v> Access = public | protected | private</v> + <v> Tweaks = {write_concurrency,bool()} | {read_concurrency,bool()} | compressed</v> <v> Pos = int()</v> <v> HeirData = term()</v> </type> @@ -963,7 +971,7 @@ ets:select(Table,MatchSpec),</code> table is named or not. If one or more options are left out, the default values are used. This means that not specifying any options (<c>[]</c>) is the same as specifying - <c>[set,protected,{keypos,1},{heir,none},{write_concurrency,false}]</c>.</p> + <c>[set,protected,{keypos,1},{heir,none},{write_concurrency,false},{read_concurrency,false}]</c>.</p> <list type="bulleted"> <item> <p><c>set</c> @@ -1002,12 +1010,14 @@ ets:select(Table,MatchSpec),</code> Any process may read or write to the table.</p> </item> <item> + <marker id="protected"></marker> <p><c>protected</c> The owner process can read and write to the table. Other processes can only read the table. This is the default setting for the access rights.</p> </item> <item> + <marker id="private"></marker> <p><c>private</c> Only the owner process can read or write to the table.</p> </item> @@ -1041,13 +1051,13 @@ ets:select(Table,MatchSpec),</code> <item> <marker id="new_2_write_concurrency"></marker> <p><c>{write_concurrency,bool()}</c> - Performance tuning. Default is <c>false</c>. An operation that + Performance tuning. Default is <c>false</c>, in which case an operation that mutates (writes to) the table will obtain exclusive access, blocking any concurrent access of the same table until finished. If set to <c>true</c>, the table is optimized towards concurrent write access. Different objects of the same table can be mutated (and read) by concurrent processes. This is achieved to some degree - at the expense of single access and concurrent reader performance. + at the expense of sequential access and concurrent reader performance. The <c>write_concurrency</c> option can be combined with the <seealso marker="#new_2_read_concurrency">read_concurrency</seealso> option. You typically want to combine these when large concurrent @@ -1085,6 +1095,15 @@ ets:select(Table,MatchSpec),</code> option. You typically want to combine these when large concurrent read bursts and large concurrent write bursts are common.</p> </item> + <item> + <marker id="new_2_compressed"></marker> + <p><c>compressed</c> + If this option is present, the table data will be stored in a more compact format to + consume less memory. The downside is that it will make table operations slower. + Especially operations that need to inspect entire objects, + such as <c>match</c> and <c>select</c>, will get much slower. The key element + is not compressed in current implementation.</p> + </item> </list> </desc> </func> |