Re: [Maria-developers] fab8349af86: MDEV-21804 Assertion `marked_for_read()' failed upon INSERT into table with long unique blob under binlog_row_image=NOBLOB

Hi, Sachin! On May 31, Sachin wrote:

revision-id: fab8349af86 (mariadb-10.4.11-223-gfab8349af86) parent(s): 61b2cd38d48 author: Sachin committer: Sachin timestamp: 2020-05-29 11:56:45 +0530 message:

MDEV-21804 Assertion `marked_for_read()' failed upon INSERT into table with long unique blob under binlog_row_image=NOBLOB

Problem:- In the case of BINLOG_ROW_IMAGE_NOBLOB table->readset is PKE + non blob fields But while updating virtual fields we need to read the blob field, which will generate assert failure. Solution:- If binlog_row_image == NOBLOB, then set read_bit for the blob field. This bug is not specific for long unique, It also fails for this case create table t2(id int primary key, a blob, b varchar(20) as (LEFT(a,2)));

diff --git a/sql/field.cc b/sql/field.cc index 0a8fdc3d3f5..bcad056e76a 100644 --- a/sql/field.cc +++ b/sql/field.cc @@ -8467,6 +8467,10 @@ longlong Field_blob::val_int(void) String *Field_blob::val_str(String *val_buffer __attribute__((unused)), String *val_ptr) { + ulong binlog_row_image= table->in_use->variables.binlog_row_image; + if (table->read_set && !bitmap_is_set(table->read_set, field_index) && + binlog_row_image == BINLOG_ROW_IMAGE_NOBLOB) + bitmap_set_bit(table->read_set, field_index); DBUG_ASSERT(marked_for_read()); char *blob; memcpy(&blob, ptr+packlength, sizeof(char*));

A couple of red flags here. First, you don't fix BINLOG_ROW_IMAGE_MINIMAL. And generally you should not modify read/write sets from val_str, if should be done earlier before the execution phase. Regards, Sergei VP of MariaDB Server Engineering and security@mariadb.org