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#3252 ✓duplicate
David Lee

add_index on postgresql with long index names: migrations fail with Input string is longer than NAMEDATALEN-1 (63)

Reported by David Lee | September 24th, 2009 @ 01:16 AM

as of 2.3.4, migration will error out if the autogenerated index name is longer than 64 chars with:

Input string is longer than NAMEDATALEN-1 (63)

Previously, such long index names would be truncated (and appear so in schema.rb) but not cause an error.

Some discussion here: identifies the cause of the problem:


I looked at the rails source code and the function that builds the index name, add_index() in schema_statements.rb, has not changed between versions 2.2.2 and 2.3.3. However postgresql_adapter.rb's function quote_column_name() now invokes pgconn_s_quote_ident() in ruby-pg, which performs the check on NAMEDATALEN.


Comments and changes to this ticket

  • CancelProfileIsBroken

    CancelProfileIsBroken September 25th, 2009 @ 11:51 AM

    • Tag changed from 2.3.4, add_index, migrations, postgresql to 2.3.4, add_index, bugmash, migrations, postgresql
  • Sebastian A. Espindola

    Sebastian A. Espindola September 25th, 2009 @ 04:09 PM

    This work has bitten me to.
    I verified the same behaviour with the postgres driver
    when trying to create a 4 fields long composite index.
    I'm working on a patch to truncate index names to the max
    identifier size.

    Will have it uploaded in a couple hours.

  • Ben Woodcroft

    Ben Woodcroft September 26th, 2009 @ 01:29 AM

    For me, the same thing occurs for remove_index, presumably for the same reason. As with add_index, using the :name option worked around it.

  • Ben Woodcroft

    Ben Woodcroft January 2nd, 2010 @ 05:44 AM

    • Tag changed from 2.3.4, add_index, bugmash, migrations, postgresql to 2.3.4, 2.3.5, add_index, bugmash, migrations, postgresql

    still true as of 2.3.5

  • Matt Jones

    Matt Jones January 4th, 2010 @ 07:18 PM

    There's a more general issue where the AR adapters don't have any details about the various adapter's limits; see #3452 for a patch I'm working on to clean up the behavior of add_index and friends. It needs some rewriting, but could be useful in cases like this.

    BTW, is there a coherent place where these limits are defined for PG? I had a heck of a time trying to find documentation for any of the supporting DBs that actually specified hard limits.

  • Rizwan Reza

    Rizwan Reza February 12th, 2010 @ 12:46 PM

    • Tag changed from 2.3.4, 2.3.5, add_index, bugmash, migrations, postgresql to 2.3.4, 2.3.5, add_index, migrations, postgresql
  • Incite

    Incite March 23rd, 2010 @ 12:23 AM

    You can find PG defaults in pg_config_manual.h which should generally be available since you need postgres headers to install the gem. Specifically, NAMEDATALEN

  • Jeremy Kemper

    Jeremy Kemper April 23rd, 2010 @ 06:04 PM

    • State changed from “new” to “duplicate”

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