MDEV-15592 - Column COMPRESSED should select a 'high order' datatype

Compressed blob columns didn't accept data at their capacity. E.g. storing
255 bytes to TINYBLOB results in "Data too long" error.

Now it is allowed assuming compression method was able to produce shorter
string (so that both metadata and compressed data fits blob) and
column_compression_threshold is lower than blob.

If no compression was performed, we still have to reserve additional byte
for metadata and thus we perform normal data truncation and return it's
status.

2 files changed, 91 insertions, 4 deletions

diff --git a/mysql-test/main/column_compression.result b/mysql-test/main/column_compression.result
index f4eb0461ed3..ace65387181 100644
--- a/mysql-test/main/column_compression.result
+++ b/mysql-test/main/column_compression.result
@@ -1336,15 +1336,33 @@ a	LENGTH(a)
 DROP TABLE t1;
 CREATE TABLE t1(a TINYTEXT COMPRESSED);
 SET column_compression_threshold=300;
+INSERT INTO t1 VALUES(REPEAT('a', 254));
+INSERT INTO t1 VALUES(REPEAT(' ', 254));
 INSERT INTO t1 VALUES(REPEAT('a', 255));
 ERROR 22001: Data too long for column 'a' at row 1
 INSERT INTO t1 VALUES(REPEAT(' ', 255));
 Warnings:
 Note	1265	Data truncated for column 'a' at row 1
+INSERT INTO t1 VALUES(REPEAT('a', 256));
+ERROR 22001: Data too long for column 'a' at row 1
+INSERT INTO t1 VALUES(REPEAT(' ', 256));
+Warnings:
+Note	1265	Data truncated for column 'a' at row 1
+Note	1265	Data truncated for column 'a' at row 1
+INSERT INTO t1 VALUES(REPEAT('a', 257));
+ERROR 22001: Data too long for column 'a' at row 1
+INSERT INTO t1 VALUES(REPEAT(' ', 257));
+Warnings:
+Note	1265	Data truncated for column 'a' at row 1
+Note	1265	Data truncated for column 'a' at row 1
 SET column_compression_threshold=DEFAULT;
-SELECT a, LENGTH(a) FROM t1;
-a	LENGTH(a)
-                                                                                                                                                                                                                                                              	254
+SELECT LEFT(a, 10), LENGTH(a) FROM t1 ORDER BY 1;
+LEFT(a, 10)	LENGTH(a)
+          	254
+          	254
+          	254
+          	254
+aaaaaaaaaa	254
 DROP TABLE t1;
 # Corner case: VARCHAR(255) COMPRESSED must have 2 bytes pack length
 CREATE TABLE t1(a VARCHAR(255) COMPRESSED);
@@ -1360,6 +1378,32 @@ SELECT a, LENGTH(a) FROM t1;
 a	LENGTH(a)
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa	255
 DROP TABLE t1;
+CREATE TABLE t1(a VARCHAR(65531) COMPRESSED);
+SET column_compression_threshold=65537;
+INSERT INTO t1 VALUES(REPEAT('a', 65530));
+INSERT INTO t1 VALUES(REPEAT(' ', 65530));
+INSERT INTO t1 VALUES(REPEAT('a', 65531));
+INSERT INTO t1 VALUES(REPEAT(' ', 65531));
+INSERT INTO t1 VALUES(REPEAT('a', 65532));
+ERROR 22001: Data too long for column 'a' at row 1
+INSERT INTO t1 VALUES(REPEAT(' ', 65532));
+Warnings:
+Note	1265	Data truncated for column 'a' at row 1
+INSERT INTO t1 VALUES(REPEAT('a', 65533));
+ERROR 22001: Data too long for column 'a' at row 1
+INSERT INTO t1 VALUES(REPEAT(' ', 65533));
+Warnings:
+Note	1265	Data truncated for column 'a' at row 1
+SET column_compression_threshold=DEFAULT;
+SELECT LEFT(a, 10), LENGTH(a) FROM t1 ORDER BY 1, 2;
+LEFT(a, 10)	LENGTH(a)
+          	65530
+          	65531
+          	65531
+          	65531
+aaaaaaaaaa	65530
+aaaaaaaaaa	65531
+DROP TABLE t1;
 #
 # MDEV-14929 - AddressSanitizer: memcpy-param-overlap in
 #              Field_longstr::compress
@@ -1419,3 +1463,12 @@ COLUMN_NAME	CHARACTER_MAXIMUM_LENGTH	CHARACTER_OCTET_LENGTH
 a	10	10
 b	10	30
 DROP TABLE t1;
+#
+# MDEV-15592 - Column COMPRESSED should select a 'high order' datatype
+#
+CREATE TABLE t1(a TINYTEXT COMPRESSED);
+INSERT INTO t1 VALUES(REPEAT('a', 255));
+SELECT LEFT(a, 10), LENGTH(a) FROM t1;
+LEFT(a, 10)	LENGTH(a)
+aaaaaaaaaa	255
+DROP TABLE t1;
diff --git a/mysql-test/main/column_compression.test b/mysql-test/main/column_compression.test
index cdd9adb254d..f3220503694 100644
--- a/mysql-test/main/column_compression.test
+++ b/mysql-test/main/column_compression.test
@@ -64,11 +64,19 @@ DROP TABLE t1;
 
 CREATE TABLE t1(a TINYTEXT COMPRESSED);
 SET column_compression_threshold=300;
+INSERT INTO t1 VALUES(REPEAT('a', 254));
+INSERT INTO t1 VALUES(REPEAT(' ', 254));
 --error ER_DATA_TOO_LONG
 INSERT INTO t1 VALUES(REPEAT('a', 255));
 INSERT INTO t1 VALUES(REPEAT(' ', 255));
+--error ER_DATA_TOO_LONG
+INSERT INTO t1 VALUES(REPEAT('a', 256));
+INSERT INTO t1 VALUES(REPEAT(' ', 256));
+--error ER_DATA_TOO_LONG
+INSERT INTO t1 VALUES(REPEAT('a', 257));
+INSERT INTO t1 VALUES(REPEAT(' ', 257));
 SET column_compression_threshold=DEFAULT;
-SELECT a, LENGTH(a) FROM t1;
+SELECT LEFT(a, 10), LENGTH(a) FROM t1 ORDER BY 1;
 DROP TABLE t1;
 
 --echo # Corner case: VARCHAR(255) COMPRESSED must have 2 bytes pack length
@@ -80,6 +88,22 @@ SET column_compression_threshold=DEFAULT;
 SELECT a, LENGTH(a) FROM t1;
 DROP TABLE t1;
 
+CREATE TABLE t1(a VARCHAR(65531) COMPRESSED);
+SET column_compression_threshold=65537;
+INSERT INTO t1 VALUES(REPEAT('a', 65530));
+INSERT INTO t1 VALUES(REPEAT(' ', 65530));
+INSERT INTO t1 VALUES(REPEAT('a', 65531));
+INSERT INTO t1 VALUES(REPEAT(' ', 65531));
+--error ER_DATA_TOO_LONG
+INSERT INTO t1 VALUES(REPEAT('a', 65532));
+INSERT INTO t1 VALUES(REPEAT(' ', 65532));
+--error ER_DATA_TOO_LONG
+INSERT INTO t1 VALUES(REPEAT('a', 65533));
+INSERT INTO t1 VALUES(REPEAT(' ', 65533));
+SET column_compression_threshold=DEFAULT;
+SELECT LEFT(a, 10), LENGTH(a) FROM t1 ORDER BY 1, 2;
+DROP TABLE t1;
+
 
 --echo #
 --echo # MDEV-14929 - AddressSanitizer: memcpy-param-overlap in
@@ -113,6 +137,7 @@ INSERT INTO t1 VALUES('a');
 SET column_compression_threshold=DEFAULT;
 DROP TABLE t1;
 
+
 --echo #
 --echo # MDEV-15938 - TINYTEXT CHARACTER SET utf8 COMPRESSED truncates data
 --echo #
@@ -136,3 +161,12 @@ FROM INFORMATION_SCHEMA.COLUMNS
 WHERE TABLE_SCHEMA='test' AND TABLE_NAME='t1' AND COLUMN_NAME IN ('a','b')
 ORDER BY COLUMN_NAME;
 DROP TABLE t1;
+
+
+--echo #
+--echo # MDEV-15592 - Column COMPRESSED should select a 'high order' datatype
+--echo #
+CREATE TABLE t1(a TINYTEXT COMPRESSED);
+INSERT INTO t1 VALUES(REPEAT('a', 255));
+SELECT LEFT(a, 10), LENGTH(a) FROM t1;
+DROP TABLE t1;