<div class="WordSection1"><p class="MsoNormal"><span lang="EN" style="font-size:13.0pt;font-family:"Courier
New";color:black">OnWed, Feb 1, 2012 at 5:23 AM, Chetan Suttraway</span><p class="MsoNormal"><span lang="EN"
style="font-size:13.0pt;font-family:"CourierNew";color:black"><chetan(dot)suttraway(at)enterprisedb(dot)com>
wrote:</span><pclass="MsoNormal"><span lang="EN" style="font-size:13.0pt;font-family:"Courier New";color:black">> Hi
All,</span><pclass="MsoNormal"><span lang="EN" style="font-size:13.0pt;font-family:"Courier
New";color:black">> </span><pclass="MsoNormal"><span lang="EN" style="font-size:13.0pt;font-family:"Courier
New";color:black">>This is regarding the TODO item :</span><p class="MsoNormal"><span lang="EN"
style="font-size:13.0pt;font-family:"CourierNew";color:black">> "Add SPI_gettypmod() to return a field's typemod
froma TupleDesc"</span><p class="MsoNormal"><span lang="EN" style="font-size:13.0pt;font-family:"Courier
New";color:black">> </span><pclass="MsoNormal"><span lang="EN" style="font-size:13.0pt;font-family:"Courier
New";color:black">>The related message is:</span><p class="MsoNormal"><span lang="EN"
style="font-size:13.0pt;font-family:"CourierNew";color:black">> <a
href="http://archives.postgresql.org/pgsql-hackers/2005-11/msg00250.php">http://archives.postgresql.org/pgsql-hackers/2005-11/msg00250.php</a></span><p
class="MsoNormal"><spanlang="EN" style="font-size:13.0pt;font-family:"Courier New";color:black">> </span><p
class="MsoNormal"><spanlang="EN" style="font-size:13.0pt;font-family:"Courier New";color:black">> This basically
talksabout having an SPI_gettypemod() which returns the</span><p class="MsoNormal"><span lang="EN"
style="font-size:13.0pt;font-family:"CourierNew";color:black">> typmod of a field of tupdesc</span><p
class="MsoNormal"><spanlang="EN" style="font-size:13.0pt;font-family:"Courier New";color:black">> </span><p
class="MsoNormal"><spanlang="EN" style="font-size:13.0pt;font-family:"Courier New";color:black">> Please refer the
attachedpatch based on the suggested implementation.</span><p class="MsoNormal"><span lang="EN"
style="font-size:13.0pt;font-family:"CourierNew";color:black"> </span><p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">Here'smy review of this patch.</span><br /><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">Basicstuff:</span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">------------</span><br/><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">-Patch applies OK </span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">-Compiles cleanly with no warnings</span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">-Regression tests pass.</span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">-Documentation changes missing</span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> - "43.2. Interface Support Functions" need to add
informationabout "SPI_gettypmod".</span><br /><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> as
wellas need to add the Description about "SPI_gettypmod".</span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">Whatit does:</span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">----------------------</span><br/><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> New SPI interface function is exposed. </span><p
class="MsoNormal"><spanstyle="font-size:10.0pt;font-family:"Arial","sans-serif""> It is used for returning the
atttypmodof the specified column. </span><p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> Ifattribute number is out of range then set the
SPI_resultto "SPI_ERROR_NOATTRIBUTE" and returns -1 else returns attributes typmod </span><br /><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">Testing:</span><br/><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">-------------------</span><br/><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> Created C function and validated type mode for </span><br
/><spanstyle="font-size:10.0pt;font-family:"Arial","sans-serif""> - output basic data types</span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> - numeric, varchar with valid typmod</span><br /><br
/><spanstyle="font-size:7.5pt">=================C-Function=============================</span><br /><span
style="font-size:7.5pt"> PG_FUNCTION_INFO_V1(test_SPI_gettypmod);</span><br /><span style="font-size:7.5pt">
Datum</span><br /><span style="font-size:7.5pt"> test_SPI_gettypmod(PG_FUNCTION_ARGS)</span><br /><span
style="font-size:7.5pt"> {</span><br /><span style="font-size:7.5pt"> Oid
relid= PG_GETARG_OID(0);</span><br /><span style="font-size:7.5pt"> Oid AttidNo
=PG_GETARG_OID(1);</span><br /><span style="font-size:7.5pt"> Relation rel;</span><br /><span
style="font-size:7.5pt"> TupleDesc tupdesc; /* tuple description */</span><br
/><spanstyle="font-size:7.5pt"> int4 retval; </span><br /><br /><span
style="font-size:7.5pt"> rel = relation_open(relid, NoLock);</span><br /><span style="font-size:7.5pt">
if (!rel)</span><br /><span style="font-size:7.5pt"> {</span><br /><span
style="font-size:7.5pt"> PG_RETURN_INT32(0);</span><br /><span style="font-size:7.5pt">
}</span><br /><span style="font-size:7.5pt"> </span><br /><span style="font-size:7.5pt">
tupdesc= rel->rd_att;</span><br /><span style="font-size:7.5pt"> retval = SPI_gettypmod(tupdesc,
AttidNo);</span><br/><span style="font-size:7.5pt"> relation_close(rel, NoLock);</span><br /><span
style="font-size:7.5pt"> PG_RETURN_INT32(retval);</span><br /><span style="font-size:7.5pt">
}</span><br/><br /><span style="font-size:7.5pt">==============Function
creation==================================</span><br/><span style="font-size:7.5pt"> CREATE FUNCTION
test_spi_gettypmod(oid, int) RETURNS int AS '/lib/mytest.so','test_SPI_gettypmod' LANGUAGE C STRICT;</span><br /><br
/><spanstyle="font-size:7.5pt">===============Output=============================================</span><br /><span
style="font-size:7.5pt">postgres=#\d tbl</span><br /><span style="font-size:7.5pt"> Table
"public.tbl"</span><br/><span style="font-size:7.5pt"> Column | Type | Modifiers</span><br
/><spanstyle="font-size:7.5pt">--------+-----------------------------+-----------</span><br /><span
style="font-size:7.5pt"> a | integer |</span><br /><span style="font-size:7.5pt"> b |
charactervarying(100) |</span><br /><span style="font-size:7.5pt"> c | numeric(10,5)
|</span><br/><span style="font-size:7.5pt"> d | numeric |</span><br /><span
style="font-size:7.5pt"> e | character varying |</span><br /><span style="font-size:7.5pt"> f |
timestampwithout time zone |</span><br /><br /><span style="font-size:7.5pt">postgres=# \d tt1</span><br /><span
style="font-size:7.5pt"> Table "public.tt1"</span><br /><span style="font-size:7.5pt"> Column |
Type | Modifiers</span><br /><span
style="font-size:7.5pt">--------+------------------------+-----------</span><br/><span style="font-size:7.5pt"> t
|tbl |</span><br /><span style="font-size:7.5pt"> b | character varying(200) |</span><br /><br
/><spanstyle="font-size:7.5pt">postgres=# select atttypmod, attname from pg_attribute where attrelid = 24577;</span><br
/><spanstyle="font-size:7.5pt"> atttypmod | attname</span><br /><span
style="font-size:7.5pt">-----------+----------</span><br/><span style="font-size:7.5pt"> -1 | tableoid</span><br
/><spanstyle="font-size:7.5pt"> -1 | cmax</span><br /><span style="font-size:7.5pt"> -1 | xmax</span><br
/><spanstyle="font-size:7.5pt"> -1 | cmin</span><br /><span style="font-size:7.5pt"> -1 | xmin</span><br
/><spanstyle="font-size:7.5pt"> -1 | ctid</span><br /><span style="font-size:7.5pt"> -1 | a</span><br
/><spanstyle="font-size:7.5pt"> 104 | b</span><br /><span style="font-size:7.5pt"> 655369 | c</span><br
/><spanstyle="font-size:7.5pt">(9 rows)</span><br /><br /><span style="font-size:7.5pt">postgres=# select
test_spi_gettypmod(24577,3);</span><br /><span style="font-size:7.5pt"> test_spi_gettypmod</span><br /><span
style="font-size:7.5pt">--------------------</span><br/><span style="font-size:7.5pt"> 655369</span><br
/><spanstyle="font-size:7.5pt">(1 row)</span><br /><br /><span style="font-size:7.5pt">postgres=# alter table tbl add
columnd numeric;</span><br /><span style="font-size:7.5pt">ALTER TABLE</span><br /><span
style="font-size:7.5pt">postgres=#alter table tbl add column e varchar;</span><br /><span style="font-size:7.5pt">ALTER
TABLE</span><br/><span style="font-size:7.5pt">postgres=# select test_spi_gettypmod(24577, 4);</span><br /><span
style="font-size:7.5pt"> test_spi_gettypmod</span><br/><span style="font-size:7.5pt">--------------------</span><br
/><spanstyle="font-size:7.5pt"> -1</span><br /><span style="font-size:7.5pt">(1 row)</span><br /><br
/><spanstyle="font-size:7.5pt">postgres=# select test_spi_gettypmod(24577, 5);</span><br /><span
style="font-size:7.5pt"> test_spi_gettypmod</span><br/><span style="font-size:7.5pt">--------------------</span><br
/><spanstyle="font-size:7.5pt"> -1</span><br /><span style="font-size:7.5pt">(1 row)</span><br /><br
/><spanstyle="font-size:7.5pt">postgres=# select test_spi_gettypmod( 24592, 1);</span><br /><span
style="font-size:7.5pt"> test_spi_gettypmod</span><br/><span style="font-size:7.5pt">--------------------</span><br
/><spanstyle="font-size:7.5pt"> -1</span><br /><span style="font-size:7.5pt">(1 row)</span><br /><br
/><br/><span style="font-size:7.5pt">postgres=# alter table tt1 add column b varchar(200);</span><br /><span
style="font-size:7.5pt">ALTERTABLE</span><br /><span style="font-size:7.5pt">postgres=# select test_spi_gettypmod(
24592,2);</span><br /><span style="font-size:7.5pt"> test_spi_gettypmod</span><br /><span
style="font-size:7.5pt">--------------------</span><br/><span style="font-size:7.5pt"> 204</span><br
/><spanstyle="font-size:7.5pt">(1 row)</span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">============================================================</span><br
/><br/><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Conclusion:</span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">-------------------</span><br/><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> Thepatch changes are okay but needs documentation update, So
Iam marking it as Waiting On Author</span><p class="MsoNormal"><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> 1. For such kind of patch, even if new regression test is
notadded, it is okay.</span><br /><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> 2. Documentation
needto be updated.</span><br /><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> 3. In case attribute
numberis not in valid range, currently it return -1, but -1 is a valid typmod. </span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> Committer can verify if this is appropriate.</span><br
/><spanstyle="font-size:10.0pt;font-family:"Arial","sans-serif""> 4. In functions exec_eval_datum &
exec_get_datum_type_infoaccording to me if we use SPI_gettypmod() to get the </span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> attribute typmod, it is better as </span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> a. there is comment /* XXX there's no SPI_gettypmod,
forsome reason */" and it uses SPI_gettypeid to get the typeid.</span><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> b. it will maintain consistency of nearby code such as
itwill use functions to get typeid and binval.</span><br /><br /><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> However there are other places in code which has
similarinconsistency.</span><br /><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> Committer can
suggestif these changes are required. </span><p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span><pclass="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span><pclass="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">WithRegards,</span><p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif"">AmitKapila.</span></div>
