Gbase 8C transaction ID and snapshot (III)

slice(hstore, text[])

describe ： extract hstore Subset .

Return value ： hstore

Example ：

 gbase=# select slice('a=>1,b=>2,c=>3'::hstore, ARRAY['b','c','x']);

       slice

--------------------

 "b"=>"2", "c"=>"3"

(1 row)

slice_array(hstore, text[])

describe ： extract hstore The set of values of .

Return value ： An array of values

Example ：

 gbase=# select slice_array('a=>1,b=>2,c=>3'::hstore, ARRAY['b','c','x']);

 slice_array

-------------

 {2,3,NULL}

(1 row)

skeys(hstore)

describe ： return hstore A set of all the keys of .

Return value ： The set of keys .

Example ：

 gbase=# select skeys('a=>1,b=>2');

 skeys

-------

 a

 b

(2 rows)

pg_control_system()

describe ： Return to system control file status .

Return type ：SETOF record

pg_control_checkpoint()

describe ： Return to system checkpoint status .

Return type ：SETOF record

pv_builtin_functions

describe ： View all built-in system function information .

Parameters ：nan

return type ：proname name, pronamespace oid, proowner oid, prolang oid, procost real, prorows real, provariadic oid, protransform regproc, proisagg boolean, proiswindow boolean, prosecdef boolean, proleakproof boolean, proisstrict boolean, proretset boolean, provolatile “char”, pronargs smallint, pronargdefaults smallint, prorettype oid, proargtypes oidvector, proallargtypes integer[], proargmodes “char”[], proargnames text[], proargdefaults pg_node_tree, prosrc text, probin text, proconfig text[], proacl aclitem[], prodefaultargpos int2vector, fencedmode boolean, proshippable boolean, propackage boolean, oid oid

pv_thread_memory_detail

describe ： Return the memory information of each thread .

Parameters ：nan

return type ：threadid text, tid bigint, thrdtype text, contextname text, level smallint, parent text, totalsize bigint, freesize bigint, usedsize bigint

pg_relation_compression_ratio

describe ： Query table compression ratio , Default return 1.0.

Parameters ：text

return type ：real

pg_relation_with_compression

describe ： Query whether the table is compressed .

Parameters ：text

return type ：boolean

pg_stat_file_recursive

describe ： List all files under the path .

Parameters ：location text