Java Code Examples for org.apache.hadoop.hbase.regionserver.HRegion#releaseRowLock()

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Example 1
Source File: MetaDataEndpointImpl.java    From phoenix with BSD 3-Clause "New" or "Revised" License 4 votes vote down vote up 
private static void releaseLocks(HRegion region, List<Integer> lids) {
    for (Integer lid : lids) {
        region.releaseRowLock(lid);
    }
}
Example 2
Source File: MetaDataEndpointImpl.java    From phoenix with BSD 3-Clause "New" or "Revised" License 4 votes vote down vote up 
private PTable doGetTable(byte[] key, long clientTimeStamp) throws IOException, SQLException {
    ImmutableBytesPtr cacheKey = new ImmutableBytesPtr(key);
    Map<ImmutableBytesPtr,PTable> metaDataCache = GlobalCache.getInstance(this.getEnvironment()).getMetaDataCache();
    PTable table = metaDataCache.get(cacheKey);
    // We only cache the latest, so we'll end up building the table with every call if the client connection has specified an SCN.
    // TODO: If we indicate to the client that we're returning an older version, but there's a newer version available, the client
    // can safely not call this, since we only allow modifications to the latest.
    if (table != null && table.getTimeStamp() < clientTimeStamp) {
        // Table on client is up-to-date with table on server, so just return
        if (isTableDeleted(table)) {
            return null;
        }
        return table;
    }
    // Ask Lars about the expense of this call - if we don't take the lock, we still won't get partial results
    // get the co-processor environment
    RegionCoprocessorEnvironment env = getEnvironment();
    // TODO: check that key is within region.getStartKey() and region.getEndKey()
    // and return special code to force client to lookup region from meta.
    HRegion region = env.getRegion();
    /*
     * Lock directly on key, though it may be an index table.
     * This will just prevent a table from getting rebuilt
     * too often.
     */
    Integer lid = region.getLock(null, key, true);
    if (lid == null) {
        throw new IOException("Failed to acquire lock on " + Bytes.toStringBinary(key));
    }
    try {
        // Try cache again in case we were waiting on a lock
        table = metaDataCache.get(cacheKey);
        // We only cache the latest, so we'll end up building the table with every call if the client connection has specified an SCN.
        // TODO: If we indicate to the client that we're returning an older version, but there's a newer version available, the client
        // can safely not call this, since we only allow modifications to the latest.
        if (table != null && table.getTimeStamp() < clientTimeStamp) {
            // Table on client is up-to-date with table on server, so just return
            if (isTableDeleted(table)) {
                return null;
            }
            return table;
        }
        // Query for the latest table first, since it's not cached
        table = buildTable(key, cacheKey, region, HConstants.LATEST_TIMESTAMP);
        if (table != null && table.getTimeStamp() < clientTimeStamp) {
            return table;
        }
        // Otherwise, query for an older version of the table - it won't be cached 
        return buildTable(key, cacheKey, region, clientTimeStamp);
    } finally {
        if (lid != null) region.releaseRowLock(lid);
    }
}