I have the same error.
It seems to be a similar problem which is also described here:
https://discuss.gogs.io/t/solved-mysql-error-1064-while-running-first-install/1604/3

I tried these options in mysql (mariadb):
SET GLOBAL innodb_file_format=Barracuda;
SET GLOBAL innodb_file_per_table=ON;
innodb_large_prefix=1

But the create statements of the tables should have (which is not the case):
ROW_FORMAT=DYNAMIC;

For me, it doesn't work. Do you confirm those commands don't solve the issue?

have the same problem, but I have already read, upgrading mysql to 5.7 should solve the problem. I'll write later again, when i solved it

Debian 9 uses MariaDB 10.1, that should be mySQL compatible, but it's not mySQL.

I upgraded to MariaDB 10.2 and now it works. :)

Here a short description how i get it working.. it is very laborious but it works for me:

1. Create your gogs database as usual
2. Visit the install page
3. Type in your data (database, user, etc.)
4. Click on Button "Install"
   -> It will fail with: 'Error 1709: Index column size too large. The maximum column size is 767 bytes.'
   BUT the tables were partially created.

To see which tables are currently present:
use gogs; (gogs = your gogs database name!)
SHOW TABLE STATUS;

5. Alter the tables with the following command:
   ALTER TABLE _tablename_ ROW_FORMAT=DYNAMIC;

6. Now go back to step 2 and repeat it. Always alter all "new" tables which were created.

After 4 or 5 rounds you get every needed table and it's done.

I am not completely sure whether you have to set the above mentioned options. I have done that.

Good luck.

It works! Thank you very much.
It would be nice to have this process automatic (what should change in gogs code?).

@playmyskay Thanks a lot for the solution that worked for me too on
mysql Ver 15.1 Distrib 10.0.32-MariaDB, for debian-linux-gnu (i686) using readline 5.2
on debian 8

Because of mysql 5.6 (includes prior versions) InnoDB max index length is 767 bytes, mysql 5.7.7 is up to 3072 bytes.
If some varchar column's length is 255, when the character format is utf-8 needs 255*3=765 bytes for index length, It's OK.
But, an utf8mb needs 255*4=1020 bytes for index length.

Solutions:

• UPGRADE the mysql to 5.7.7(Mariadb 10.2.2)
• Change the utf8mb column length to 191 (191*4=764)
• Change the utf8mb to utf8
• set innodb_file_format=Barracuda, innodb_large_prefix=on and create table using ROW_FORMAT=DYNAMIC or COMPRESSED (default for 5.7.7)

I will fix it later.

Hi, on Debian 9 with MariaDB this sill seems to be much of an hassle. Just to save someone else a bit time, dump this repeatedly to the SQL prompt until Gogs install finishes:

ALTER TABLE `access` ROW_FORMAT=DYNAMIC;
ALTER TABLE `access_token` ROW_FORMAT=DYNAMIC;
ALTER TABLE `action` ROW_FORMAT=DYNAMIC;
ALTER TABLE `attachment` ROW_FORMAT=DYNAMIC;
ALTER TABLE `collaboration` ROW_FORMAT=DYNAMIC;
ALTER TABLE `comment` ROW_FORMAT=DYNAMIC;
ALTER TABLE `deploy_key` ROW_FORMAT=DYNAMIC;
ALTER TABLE `follow` ROW_FORMAT=DYNAMIC;
ALTER TABLE `hook_task` ROW_FORMAT=DYNAMIC;
ALTER TABLE `issue` ROW_FORMAT=DYNAMIC;
ALTER TABLE `issue_label` ROW_FORMAT=DYNAMIC;
ALTER TABLE `issue_user` ROW_FORMAT=DYNAMIC;
ALTER TABLE `label` ROW_FORMAT=DYNAMIC;
ALTER TABLE `login_source` ROW_FORMAT=DYNAMIC;
ALTER TABLE `milestone` ROW_FORMAT=DYNAMIC;
ALTER TABLE `mirror` ROW_FORMAT=DYNAMIC;
ALTER TABLE `protect_branch` ROW_FORMAT=DYNAMIC;
ALTER TABLE `protect_branch_whitelist` ROW_FORMAT=DYNAMIC;
ALTER TABLE `public_key` ROW_FORMAT=DYNAMIC;
ALTER TABLE `pull_request` ROW_FORMAT=DYNAMIC;
ALTER TABLE `release` ROW_FORMAT=DYNAMIC;
ALTER TABLE `repository` ROW_FORMAT=DYNAMIC;
ALTER TABLE `star` ROW_FORMAT=DYNAMIC;
ALTER TABLE `two_factor` ROW_FORMAT=DYNAMIC;
ALTER TABLE `two_factor_recovery_code` ROW_FORMAT=DYNAMIC;
ALTER TABLE `upload` ROW_FORMAT=DYNAMIC;
ALTER TABLE `user` ROW_FORMAT=DYNAMIC;
ALTER TABLE `watch` ROW_FORMAT=DYNAMIC;
ALTER TABLE `webhook` ROW_FORMAT=DYNAMIC;