The following small patch provides a couple of minor updates (against

CVS HEAD):

Amended "strings" regression test. TOAST tests now insert two values
with storage set to "external", to exercise properly the TOAST slice
routines which fetch only a subset of the chunks.

Changed now-misleading comment on AlterTableCreateToastTable in
tablecmds.c, because both columns of the index on a toast table are now
used.

John Gray

2 files changed, 48 insertions, 6 deletions

diff --git a/src/test/regress/expected/strings.out b/src/test/regress/expected/strings.out
index 373746ca7ac..ae0b48590cf 100644
--- a/src/test/regress/expected/strings.out
+++ b/src/test/regress/expected/strings.out
@@ -579,6 +579,13 @@ SELECT text 'text' || varchar ' and varchar' AS "Concat text to varchar";
 CREATE TABLE toasttest(f1 text);
 insert into toasttest values(repeat('1234567890',10000));
 insert into toasttest values(repeat('1234567890',10000));
+--
+-- Ensure that some values are uncompressed, to test the faster substring
+-- operation used in that case
+--
+alter table toasttest alter column f1 set storage external;
+insert into toasttest values(repeat('1234567890',10000));
+insert into toasttest values(repeat('1234567890',10000));
 -- If the starting position is zero or less, then return from the start of the string
 -- adjusting the length to be consistent with the "negative start" per SQL92.
 SELECT substr(f1, -1, 5) from toasttest;
@@ -586,7 +593,9 @@ SELECT substr(f1, -1, 5) from toasttest;
 --------
  123
  123
-(2 rows)
+ 123
+ 123
+(4 rows)
 
 -- If the length is less than zero, an ERROR is thrown.
 SELECT substr(f1, 5, -1) from toasttest;
@@ -598,7 +607,9 @@ SELECT substr(f1, 99995) from toasttest;
 --------
  567890
  567890
-(2 rows)
+ 567890
+ 567890
+(4 rows)
 
 -- If start plus length is > string length, the result is truncated to
 -- string length
@@ -607,7 +618,9 @@ SELECT substr(f1, 99995, 10) from toasttest;
 --------
  567890
  567890
-(2 rows)
+ 567890
+ 567890
+(4 rows)
 
 DROP TABLE toasttest;
 --
@@ -616,6 +629,13 @@ DROP TABLE toasttest;
 CREATE TABLE toasttest(f1 bytea);
 insert into toasttest values(decode(repeat('1234567890',10000),'escape'));
 insert into toasttest values(decode(repeat('1234567890',10000),'escape'));
+--
+-- Ensure that some values are uncompressed, to test the faster substring
+-- operation used in that case
+--
+alter table toasttest alter column f1 set storage external;
+insert into toasttest values(decode(repeat('1234567890',10000),'escape'));
+insert into toasttest values(decode(repeat('1234567890',10000),'escape'));
 -- If the starting position is zero or less, then return from the start of the string
 -- adjusting the length to be consistent with the "negative start" per SQL92.
 SELECT substr(f1, -1, 5) from toasttest;
@@ -623,7 +643,9 @@ SELECT substr(f1, -1, 5) from toasttest;
 --------
  123
  123
-(2 rows)
+ 123
+ 123
+(4 rows)
 
 -- If the length is less than zero, an ERROR is thrown.
 SELECT substr(f1, 5, -1) from toasttest;
@@ -635,7 +657,9 @@ SELECT substr(f1, 99995) from toasttest;
 --------
  567890
  567890
-(2 rows)
+ 567890
+ 567890
+(4 rows)
 
 -- If start plus length is > string length, the result is truncated to
 -- string length
@@ -644,7 +668,9 @@ SELECT substr(f1, 99995, 10) from toasttest;
 --------
  567890
  567890
-(2 rows)
+ 567890
+ 567890
+(4 rows)
 
 DROP TABLE toasttest;
 --
diff --git a/src/test/regress/sql/strings.sql b/src/test/regress/sql/strings.sql
index af83a0b5715..2095848a39d 100644
--- a/src/test/regress/sql/strings.sql
+++ b/src/test/regress/sql/strings.sql
@@ -206,6 +206,14 @@ CREATE TABLE toasttest(f1 text);
 insert into toasttest values(repeat('1234567890',10000));
 insert into toasttest values(repeat('1234567890',10000));
 
+--
+-- Ensure that some values are uncompressed, to test the faster substring
+-- operation used in that case
+--
+alter table toasttest alter column f1 set storage external;
+insert into toasttest values(repeat('1234567890',10000));
+insert into toasttest values(repeat('1234567890',10000));
+
 -- If the starting position is zero or less, then return from the start of the string
 -- adjusting the length to be consistent with the "negative start" per SQL92.
 SELECT substr(f1, -1, 5) from toasttest;
@@ -231,6 +239,14 @@ CREATE TABLE toasttest(f1 bytea);
 insert into toasttest values(decode(repeat('1234567890',10000),'escape'));
 insert into toasttest values(decode(repeat('1234567890',10000),'escape'));
 
+--
+-- Ensure that some values are uncompressed, to test the faster substring
+-- operation used in that case
+--
+alter table toasttest alter column f1 set storage external;
+insert into toasttest values(decode(repeat('1234567890',10000),'escape'));
+insert into toasttest values(decode(repeat('1234567890',10000),'escape'));
+
 -- If the starting position is zero or less, then return from the start of the string
 -- adjusting the length to be consistent with the "negative start" per SQL92.
 SELECT substr(f1, -1, 5) from toasttest;