Add lo_truncate() to backend and libpq for large object truncation.

Kris Jurka

2 files changed, 83 insertions, 0 deletions

diff --git a/src/test/regress/input/largeobject.source b/src/test/regress/input/largeobject.source
index e89ce02fa9..8386922133 100644
--- a/src/test/regress/input/largeobject.source
+++ b/src/test/regress/input/largeobject.source
@@ -83,6 +83,25 @@ SELECT lo_close(fd) FROM lotest_stash_values;
 
 END;
 
+-- Test truncation.
+BEGIN;
+UPDATE lotest_stash_values SET fd=lo_open(loid, CAST((2 | 4) * 16^4 AS integer));
+
+SELECT lo_truncate(fd, 10) FROM lotest_stash_values;
+SELECT loread(fd, 15) FROM lotest_stash_values;
+
+SELECT lo_truncate(fd, 10000) FROM lotest_stash_values;
+SELECT loread(fd, 10) FROM lotest_stash_values;
+SELECT lo_lseek(fd, 0, 2) FROM lotest_stash_values;
+SELECT lo_tell(fd) FROM lotest_stash_values;
+
+SELECT lo_truncate(fd, 5000) FROM lotest_stash_values;
+SELECT lo_lseek(fd, 0, 2) FROM lotest_stash_values;
+SELECT lo_tell(fd) FROM lotest_stash_values;
+
+SELECT lo_close(fd) FROM lotest_stash_values;
+END;
+
 -- lo_unlink(lobjId oid) returns integer
 -- return value appears to always be 1
 SELECT lo_unlink(loid) from lotest_stash_values;
diff --git a/src/test/regress/output/largeobject.source b/src/test/regress/output/largeobject.source
index 6d6e5cd24c..f4addeaab5 100644
--- a/src/test/regress/output/largeobject.source
+++ b/src/test/regress/output/largeobject.source
@@ -116,6 +116,70 @@ SELECT lo_close(fd) FROM lotest_stash_values;
 (1 row)
 
 END;
+-- Test truncation.
+BEGIN;
+UPDATE lotest_stash_values SET fd=lo_open(loid, CAST((2 | 4) * 16^4 AS integer));
+SELECT lo_truncate(fd, 10) FROM lotest_stash_values;
+ lo_truncate 
+-------------
+           0
+(1 row)
+
+SELECT loread(fd, 15) FROM lotest_stash_values;
+    loread     
+---------------
+ \012Whose woo
+(1 row)
+
+SELECT lo_truncate(fd, 10000) FROM lotest_stash_values;
+ lo_truncate 
+-------------
+           0
+(1 row)
+
+SELECT loread(fd, 10) FROM lotest_stash_values;
+                  loread                  
+------------------------------------------
+ \000\000\000\000\000\000\000\000\000\000
+(1 row)
+
+SELECT lo_lseek(fd, 0, 2) FROM lotest_stash_values;
+ lo_lseek 
+----------
+    10000
+(1 row)
+
+SELECT lo_tell(fd) FROM lotest_stash_values;
+ lo_tell 
+---------
+   10000
+(1 row)
+
+SELECT lo_truncate(fd, 5000) FROM lotest_stash_values;
+ lo_truncate 
+-------------
+           0
+(1 row)
+
+SELECT lo_lseek(fd, 0, 2) FROM lotest_stash_values;
+ lo_lseek 
+----------
+     5000
+(1 row)
+
+SELECT lo_tell(fd) FROM lotest_stash_values;
+ lo_tell 
+---------
+    5000
+(1 row)
+
+SELECT lo_close(fd) FROM lotest_stash_values;
+ lo_close 
+----------
+        0
+(1 row)
+
+END;
 -- lo_unlink(lobjId oid) returns integer
 -- return value appears to always be 1
 SELECT lo_unlink(loid) from lotest_stash_values;