BTR_SEA_TIMEOUT is not applied / TRX_ADAPTIVE_HASH_TIMEOUT obsoleted

[Raghavendra D Prabhu]

Following is not applicable for PS:

/** We do this many searches before trying to keep the search latch
over calls from MySQL. If we notice someone waiting for the latch, we
again set this much timeout. This is to reduce contention. */
#define BTR_SEA_TIMEOUT 10000

This is a consequence of fix from https://bugs.launchpad.net/percona-server/+bug/1218347

So, TRX_ADAPTIVE_HASH_TIMEOUT in I_S.INNODB_TRX - https://dev.mysql.com/doc/refman/5.6/en/innodb-trx-table.html - will always show default value of initial value of 10000 (BTR_SEA_TIMEOUT) and that doesn't change over lifetime of transaction.

This needs to be documented for PS and/or also remove that column from the I_S table as well since it is obsoleted by the code in row0sel.cc.

========
 row->trx_search_latch_timeout = trx->search_latch_timeout;
        trx->search_latch_timeout = BTR_SEA_TIMEOUT;

           /* trx_adaptive_hash_timeout */
  OK(fields[IDX_TRX_ADAPTIVE_HASH_TIMEOUT]->store(
      (longlong) row->trx_search_latch_timeout, true));
=========

etc. can be elided out as well as a consequence of that.

[Laurynas Biveinis (laurynas-biveinis)]

This is a fully upstream bug for 5.7: http://bugs.mysql.com/bug.php?id=79632

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-3286