Same mysql query gives different results at different times in phpmyadmin

Question

We're running the following very simple mysql query through phpmyadmin

SELECT * FROM ProcessedListAssociations

We know the correct result has 751331 rows but successive runs of the query return different row counts - anywhere from 749978 to 752165 rows. At least that's what the row count message at the top of the phpmyadmin result page says: Showing rows 0 - 24 (752165 total, Query took 0.0005 seconds.)

Running the query from a php script seems to return a result with the correct number of rows.

Running the following query from phpmyadmin:

SELECT count(*) FROM ProcessedListAssociations

also returns the correct result (751331)

We have recreated the table from scratch & still observe the same issue.

The table is an innoDB table. Here's basic info as phpmyAdmin reports it: Space usage Data 68.6 MiB Index 136.3 MiB Total 204.9 MiB Row statistics Format Compact Collation utf8_general_ci Next autoindex 751,332

Could it have something to do with concurrency? The server has 4 E7-4870 processors (80 threads total) but in the php.ini thread Safety is disabled. If that is indeed the problem, then why are we only observing it in phpmyadmin and not with our own php scripts too?

Answer 1

See the answer for incorrect table rowcount in mysql

https://phpmyadmin.readthedocs.io/en/latest/faq.html?highlight=MaxExactCount#the-number-of-rows-for-innodb-tables-is-not-correct